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Vannini C, Marsoni M, Scoccianti V, Ceccarini C, Domingo G, Bracale M, Crinelli R. Proteasome-mediated remodeling of the proteome and phosphoproteome during kiwifruit pollen germination. J Proteomics 2019; 192:334-345. [DOI: 10.1016/j.jprot.2018.09.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 09/11/2018] [Accepted: 09/20/2018] [Indexed: 01/19/2023]
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Li Y, Wu C, Liu C, Yu J, Duan X, Fan W, Wang J, Zhang X, Yan G, Li T, Zhang K. Functional identification of lncRNAs in sweet cherry ( Prunus avium) pollen tubes via transcriptome analysis using single-molecule long-read sequencing. HORTICULTURE RESEARCH 2019; 6:135. [PMID: 31814988 PMCID: PMC6885045 DOI: 10.1038/s41438-019-0218-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 09/27/2019] [Accepted: 10/27/2019] [Indexed: 05/05/2023]
Abstract
Sweet cherry (Prunus avium) is a popular fruit with high nutritional value and excellent flavor. Although pollen plays an important role in the double fertilization and subsequent fruit production of this species, little is known about its pollen tube transcriptome. In this study, we identified 16,409 transcripts using single-molecule sequencing. After filtering 292 transposable elements, we conducted further analyses including mRNA classification, gene function prediction, alternative splicing (AS) analysis, and long noncoding RNA (lncRNA) identification to gain insight into the pollen transcriptome. The filtered transcripts could be matched with 3,438 coding region sequences from the sweet cherry genome. GO and KEGG analyses revealed complex biological processes during pollen tube elongation. A total of 2043 AS events were predicted, 7 of which were identified in different organs, such as the leaf, pistil and pollen tube. Using BLASTnt and the Coding-Potential Assessment Tool (CPAT), we distinguished a total of 284 lncRNAs, among which 154 qualified as natural antisense transcripts (NATs). As the NATs could be the reverse complements of coding mRNA sequences, they might bind to coding sequences. Antisense transfection assays showed that the NATs could regulate the expression levels of their complementary sequences and even affect the growth conditions of pollen tubes. In summary, this research characterizes the transcripts of P. avium pollen and lays the foundation for elucidating the physiological and biochemical mechanisms underlying sexual reproduction in the male gametes of this species.
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Affiliation(s)
- Yang Li
- Laboratory of Fruit Cell and Molecular Breeding, China Agricultural University, Beijing, China
| | - Chuanbao Wu
- Laboratory of Fruit Cell and Molecular Breeding, China Agricultural University, Beijing, China
| | - Chunsheng Liu
- Laboratory of Fruit Cell and Molecular Breeding, China Agricultural University, Beijing, China
| | - Jie Yu
- Laboratory of Fruit Cell and Molecular Breeding, China Agricultural University, Beijing, China
| | - Xuwei Duan
- Institute of Forestry and Pomology, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (North China), Ministry of Agriculture, Beijing, China
- Beijing Engineering Research Center for Deciduous Fruit Trees, Beijing, China
| | - Wenqi Fan
- Laboratory of Fruit Cell and Molecular Breeding, China Agricultural University, Beijing, China
| | - Jing Wang
- Institute of Forestry and Pomology, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (North China), Ministry of Agriculture, Beijing, China
- Beijing Engineering Research Center for Deciduous Fruit Trees, Beijing, China
| | - Xiaoming Zhang
- Institute of Forestry and Pomology, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (North China), Ministry of Agriculture, Beijing, China
- Beijing Engineering Research Center for Deciduous Fruit Trees, Beijing, China
| | - Guohua Yan
- Institute of Forestry and Pomology, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (North China), Ministry of Agriculture, Beijing, China
- Beijing Engineering Research Center for Deciduous Fruit Trees, Beijing, China
| | - Tianzhong Li
- Laboratory of Fruit Cell and Molecular Breeding, China Agricultural University, Beijing, China
| | - Kaichun Zhang
- Institute of Forestry and Pomology, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (North China), Ministry of Agriculture, Beijing, China
- Beijing Engineering Research Center for Deciduous Fruit Trees, Beijing, China
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Abstract
The reproductive adaptations of land plants have played a key role in their terrestrial colonization and radiation. This encompasses mechanisms used for the production, dispersal and union of gametes to support sexual reproduction. The production of small motile male gametes and larger immotile female gametes (oogamy) in specialized multicellular gametangia evolved in the charophyte algae, the closest extant relatives of land plants. Reliance on water and motile male gametes for sexual reproduction was retained by bryophytes and basal vascular plants, but was overcome in seed plants by the dispersal of pollen and the guided delivery of non-motile sperm to the female gametes. Here we discuss the evolutionary history of male gametogenesis in streptophytes (green plants) and the underlying developmental biology, including recent advances in bryophyte and angiosperm models. We conclude with a perspective on research trends that promise to deliver a deeper understanding of the evolutionary and developmental mechanisms of male gametogenesis in plants.
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Affiliation(s)
- Dieter Hackenberg
- Department of Genetics and Genome Biology, University of Leicester, Leicester, United Kingdom.
| | - David Twell
- Department of Genetics and Genome Biology, University of Leicester, Leicester, United Kingdom.
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54
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Flavonols control pollen tube growth and integrity by regulating ROS homeostasis during high-temperature stress. Proc Natl Acad Sci U S A 2018; 115:E11188-E11197. [PMID: 30413622 DOI: 10.1073/pnas.1811492115] [Citation(s) in RCA: 166] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Plant reproduction requires long-distance growth of a pollen tube to fertilize the female gametophyte. Prior reports suggested that mutations altering synthesis of flavonoids, plant specialized metabolites that include flavonols and anthocyanins, impair pollen development in several species, but the mechanism by which flavonols enhanced fertility was not defined. Here, we used genetic approaches to demonstrate that flavonols enhanced pollen development by reducing the abundance of reactive oxygen species (ROS). We further showed that flavonols reduced high-temperature stress-induced ROS accumulation and inhibition of pollen tube growth. The anthocyanin reduced (are) tomato mutant had reduced flavonol accumulation in pollen grains and tubes. This mutant produced fewer pollen grains and had impaired pollen viability, germination, tube growth, and tube integrity, resulting in reduced seed set. Consistent with flavonols acting as ROS scavengers, are had elevated levels of ROS. The pollen viability, tube growth and integrity defects, and ROS accumulation in are were reversed by genetic complementation. Inhibition of ROS synthesis or scavenging of excess ROS with an exogenous antioxidant treatment also reversed the are phenotypes, indicating that flavonols function by reducing ROS levels. Heat stress resulted in increased ROS in pollen tubes and inhibited tube growth, with more pronounced effects in the are mutant that could be rescued by antioxidant treatment. These results are consistent with increased ROS inhibiting pollen tube growth and with flavonols preventing ROS from reaching damaging levels. These results reveal that flavonol metabolites regulate plant sexual reproduction at both normal and elevated temperatures by maintaining ROS homeostasis.
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Salinas-Grenet H, Herrera-Vásquez A, Parra S, Cortez A, Gutiérrez L, Pollmann S, León G, Blanco-Herrera F. Modulation of Auxin Levels in Pollen Grains Affects Stamen Development and Anther Dehiscence in Arabidopsis. Int J Mol Sci 2018; 19:ijms19092480. [PMID: 30131475 PMCID: PMC6164920 DOI: 10.3390/ijms19092480] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 08/15/2018] [Accepted: 08/20/2018] [Indexed: 12/28/2022] Open
Abstract
Auxin regulates diverse aspects of flower development in plants, such as differentiation of the apical meristem, elongation of the stamen, and maturation of anthers and pollen. It is known that auxin accumulates in pollen, but little information regarding the biological relevance of auxin in this tissue at different times of development is available. In this work, we manipulated the amount of free auxin specifically in developing pollen, using transgenic Arabidopsis lines that express the bacterial indole-3-acetic acid-lysine synthetase (iaaL) gene driven by a collection of pollen-specific promoters. The iaaL gene codes for an indole-3-acetic acid-lysine synthetase that catalyzes the conversion of free auxin into inactive indole-3-acetyl-l-lysine. The transgenic lines showed several abnormalities, including the absence of short stamina, a diminished seed set, aberrant pollen tubes, and perturbations in the synchronization of anther dehiscence and stamina development. This article describes the importance of auxin accumulation in pollen and its role in stamina and anther development.
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Affiliation(s)
- Hernán Salinas-Grenet
- Centro de Biotecnología Vegetal, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, RM 837-0186, Chile.
| | - Ariel Herrera-Vásquez
- Centro de Biotecnología Vegetal, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, RM 837-0186, Chile.
- Millennium Institute for Integrative Systems and Synthetic Biology (MIISSB), Santiago, Chile.
| | - Samuel Parra
- Centro de Biotecnología Vegetal, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, RM 837-0186, Chile.
| | - Allan Cortez
- Centro de Biotecnología Vegetal, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, RM 837-0186, Chile.
| | - Lilian Gutiérrez
- Centro de Biotecnología Vegetal, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, RM 837-0186, Chile.
| | - Stephan Pollmann
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)⁻Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), 28223 Pozuelo de Alarcón, Spain.
| | - Gabriel León
- Centro de Biotecnología Vegetal, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, RM 837-0186, Chile.
| | - Francisca Blanco-Herrera
- Centro de Biotecnología Vegetal, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, RM 837-0186, Chile.
- Millennium Institute for Integrative Systems and Synthetic Biology (MIISSB), Santiago, Chile.
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Rosbakh S, Pacini E, Nepi M, Poschlod P. An Unexplored Side of Regeneration Niche: Seed Quantity and Quality Are Determined by the Effect of Temperature on Pollen Performance. FRONTIERS IN PLANT SCIENCE 2018; 9:1036. [PMID: 30073009 PMCID: PMC6058057 DOI: 10.3389/fpls.2018.01036] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 06/26/2018] [Indexed: 05/21/2023]
Abstract
In 1977, Peter Grubb introduced the regeneration niche concept, which assumes that a plant species cannot persist if the environmental conditions are only suitable for adult plant growth and survival, but not for seed production, dispersal, germination, and seedling establishment. During the last decade, this concept has received considerable research attention as it helps to better understand community assembly, population dynamics, and plant responses to environmental changes. Yet, in its present form, it focuses too much on the post-fertilization stages of plant sexual reproduction, neglecting the fact that the environment can operate as a constraint at many points in the chain of processes necessary for successful regeneration. In this review, we draw the attention of the plant ecology research community to the pre-fertilization stages of plant sexual reproduction, an almost ignored but important aspect of the regeneration niche, and their potential consequences for successful seed production. Particularly, we focus on how temperature affects pollen performance and determines plant reproduction success by playing an important role in the temporal and spatial variations in seed quality and quantity. We also review the pollen adaptations to temperature stresses at different levels of plant organization and discuss the plasticity of the performance of pollen under changing temperature conditions. The reviewed literature demonstrates that pre-fertilization stages of seed production, particularly the extreme sensitivity of male gametophyte performance to temperature, are the key determinants of a species' regeneration niche. Thus, we suggest that previous views stating that the regeneration niche begins with the production of seeds should be modified to include the preceding stages. Lastly, we identify several gaps in pollen-related studies revealing a framework of opportunities for future research, particularly how these findings could be used in the field of plant biology and ecology.
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Affiliation(s)
- Sergey Rosbakh
- Chair of Ecology and Conservation Biology, University of Regensburg, Regensburg, Germany
| | - Ettore Pacini
- Department of Life Sciences, University of Siena, Siena, Italy
| | - Massimo Nepi
- Department of Life Sciences, University of Siena, Siena, Italy
| | - Peter Poschlod
- Chair of Ecology and Conservation Biology, University of Regensburg, Regensburg, Germany
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Li H, Luo N, Wang W, Liu Z, Chen J, Zhao L, Tan L, Wang C, Qin Y, Li C, Xu T, Yang Z. The REN4 rheostat dynamically coordinates the apical and lateral domains of Arabidopsis pollen tubes. Nat Commun 2018; 9:2573. [PMID: 29968705 PMCID: PMC6030205 DOI: 10.1038/s41467-018-04838-w] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 05/11/2018] [Indexed: 11/08/2022] Open
Abstract
The dynamic maintenance of polar domains in the plasma membrane (PM) is critical for many fundamental processes, e.g., polar cell growth and growth guidance but remains poorly characterized. Rapid tip growth of Arabidopsis pollen tubes requires dynamic distribution of active ROP1 GTPase to the apical domain. Here, we show that clathrin-mediated endocytosis (CME) coordinates lateral REN4 with apical ROP1 signaling. REN4 interacted with but antagonized active ROP1. REN4 also interacts and co-localizes with CME components, but exhibits an opposite role to CME, which removes both REN4 and active ROP1 from the PM. Mathematical modeling shows that REN4 restrains the spatial distribution of active ROP1 and is important for the robustness of polarity control. Hence our results indicate that REN4 acts as a spatiotemporal rheostat by interacting with ROP1 to initiate their removal from the PM by CME, thereby coordinating a dynamic demarcation between apical and lateral domains during rapid tip growth.
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Affiliation(s)
- Hui Li
- Shanghai Center for Plant Stress Biology and Shanghai Institute of Plant Physiology and Ecolog, Shanghai Institutes for Biological Sciences Chinese Academy of Sciences, 201602, Shanghai, China
- Center for Plant Cell Biology, Institute of Integrative Genome Biology, and Department of Botany and Plant Sciences, University of California, Riverside, CA, 92508, USA
- School of Life Sciences, East China Normal University, 200241, Shanghai, China
| | - Nan Luo
- Center for Plant Cell Biology, Institute of Integrative Genome Biology, and Department of Botany and Plant Sciences, University of California, Riverside, CA, 92508, USA
- FAFU-UCR Joint Center for Horticultural Biology and Metebolomics, Institute of Science and Technology, Fujian Agriculture and Forestry University, 350002, Fuzhou, China
| | - Weidong Wang
- Center for Plant Cell Biology, Institute of Integrative Genome Biology, and Department of Botany and Plant Sciences, University of California, Riverside, CA, 92508, USA
| | - Zengyu Liu
- FAFU-UCR Joint Center for Horticultural Biology and Metebolomics, Institute of Science and Technology, Fujian Agriculture and Forestry University, 350002, Fuzhou, China
| | - Jisheng Chen
- Center for Plant Cell Biology, Institute of Integrative Genome Biology, and Department of Botany and Plant Sciences, University of California, Riverside, CA, 92508, USA
- FAFU-UCR Joint Center for Horticultural Biology and Metebolomics, Institute of Science and Technology, Fujian Agriculture and Forestry University, 350002, Fuzhou, China
| | - Liangtao Zhao
- Shanghai Center for Plant Stress Biology and Shanghai Institute of Plant Physiology and Ecolog, Shanghai Institutes for Biological Sciences Chinese Academy of Sciences, 201602, Shanghai, China
| | - Li Tan
- Shanghai Center for Plant Stress Biology and Shanghai Institute of Plant Physiology and Ecolog, Shanghai Institutes for Biological Sciences Chinese Academy of Sciences, 201602, Shanghai, China
| | - Chunyan Wang
- Shanghai Center for Plant Stress Biology and Shanghai Institute of Plant Physiology and Ecolog, Shanghai Institutes for Biological Sciences Chinese Academy of Sciences, 201602, Shanghai, China
| | - Yuan Qin
- FAFU-UCR Joint Center for Horticultural Biology and Metebolomics, Institute of Science and Technology, Fujian Agriculture and Forestry University, 350002, Fuzhou, China
| | - Chao Li
- School of Life Sciences, East China Normal University, 200241, Shanghai, China
| | - Tongda Xu
- Shanghai Center for Plant Stress Biology and Shanghai Institute of Plant Physiology and Ecolog, Shanghai Institutes for Biological Sciences Chinese Academy of Sciences, 201602, Shanghai, China
- FAFU-UCR Joint Center for Horticultural Biology and Metebolomics, Institute of Science and Technology, Fujian Agriculture and Forestry University, 350002, Fuzhou, China
| | - Zhenbiao Yang
- Center for Plant Cell Biology, Institute of Integrative Genome Biology, and Department of Botany and Plant Sciences, University of California, Riverside, CA, 92508, USA.
- FAFU-UCR Joint Center for Horticultural Biology and Metebolomics, Institute of Science and Technology, Fujian Agriculture and Forestry University, 350002, Fuzhou, China.
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58
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Transcriptome Analysis Provides Insight into the Molecular Mechanisms Underlying gametophyte factor 2-Mediated Cross-Incompatibility in Maize. Int J Mol Sci 2018; 19:ijms19061757. [PMID: 29899298 PMCID: PMC6032218 DOI: 10.3390/ijms19061757] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 05/12/2018] [Accepted: 05/28/2018] [Indexed: 12/26/2022] Open
Abstract
In maize (Zea mays L.), unilateral cross-incompatibility (UCI) is controlled by Gametophyte factors (Ga), including Ga1, Ga2, and Tcb1; however, the molecular mechanisms underpinning this process remain unexplored. Here, we report the pollination phenotype of an inbred line, 511L, which carries a near-dominant Ga2-S allele. We performed a high-throughput RNA sequencing (RNA-Seq) analysis of the compatible and incompatible crosses between 511L and B73, to identify the transcriptomic differences associated with Ga2-mediated UCI. An in vivo kinetics analysis revealed that the growth of non-self pollen tubes was blocked at the early stages after pollination in 511L, maintaining the UCI barrier in Ga2. In total, 25,759 genes were expressed, of which, 2063 differentially expressed genes (DEGs) were induced by pollination (G_GG, G_GB, B_BB, B_BG). A gene ontology (GO) enrichment analysis revealed that these genes were specifically enriched in functions involved in cell wall strength and pectic product modification. Moreover, 1839, 4382, and 5041 genes were detected to differentially express under same pollination treatments, including B_G, BG_GG, and BB_GB, respectively. A total of 1467 DEGs were constitutively expressed between the two inbred lines following pollination treatments, which were enriched in metabolic processes, flavonoid biosynthesis, cysteine biosynthesis, and vacuole functions. Furthermore, we confirmed 14 DEGs related to cell wall modification and stress by qRT-PCR, which might be involved in Ga2-S-mediated UCI. Our results provide a comprehensive foundation for the molecular mechanisms involved in silks of UCI mediated by Ga2-S.
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Chen W, Gong P, Guo J, Li H, Li R, Xing W, Yang Z, Guan Y. Glycolysis regulates pollen tube polarity via Rho GTPase signaling. PLoS Genet 2018; 14:e1007373. [PMID: 29702701 PMCID: PMC5942846 DOI: 10.1371/journal.pgen.1007373] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 05/09/2018] [Accepted: 04/19/2018] [Indexed: 12/25/2022] Open
Abstract
As a universal energy generation pathway utilizing carbon metabolism, glycolysis plays an important housekeeping role in all organisms. Pollen tubes expand rapidly via a mechanism of polarized growth, known as tip growth, to deliver sperm for fertilization. Here, we report a novel and surprising role of glycolysis in the regulation of growth polarity in Arabidopsis pollen tubes via impingement of Rho GTPase-dependent signaling. We identified a cytosolic phosphoglycerate kinase (pgkc-1) mutant with accelerated pollen germination and compromised pollen tube growth polarity. pgkc-1 mutation greatly diminished apical exocytic vesicular distribution of REN1 RopGAP (Rop GTPase activating protein), leading to ROP1 hyper-activation at the apical plasma membrane. Consequently, pgkc-1 pollen tubes contained higher amounts of exocytic vesicles and actin microfilaments in the apical region, and showed reduced sensitivity to Brefeldin A and Latrunculin B, respectively. While inhibition of mitochondrial respiration could not explain the pgkc-1 phenotype, the glycolytic activity is indeed required for PGKc function in pollen tubes. Moreover, the pgkc-1 pollen tube phenotype was mimicked by the inhibition of another glycolytic enzyme. These findings highlight an unconventional regulatory function for a housekeeping metabolic pathway in the spatial control of a fundamental cellular process. Glycolysis, which breaks down glucose to produce energy, has long been considered a “housekeeping” pathway in living cells, i.e., it helps maintain basic cellular functions. Here, we found that the glycolysis pathway plays an unconventional regulatory role in cell polarity, i.e., the intrinsic asymmetry in the shape, structure, and organization of cellular components. Mutation in the gene encoding the glycolytic enzyme cytosolic phosphoglycerate kinase (PGKc) leads to swollen and shorter pollen tubes in Arabidopsis thaliana, which is associated with the over-activation of Rho GTPase—a master regulator of cell polarity. Our results suggest that this phenomenon is caused by a specific regulatory role of cytosolic glycolysis rather than the global energy supply or moonlighting functions of glycolytic enzymes that modulate pollen tube growth polarity. Our findings shed light on the diverse biological roles of glycolysis in plants beyond simple “housekeeping” functions.
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Affiliation(s)
- Wei Chen
- Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences, Shanghai, China
- FAFU-UCR Joint Center for Horticultural Biology and Metabolomics, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
- University of Chinese Academy of Sciences, Shanghai, China
| | - Pingping Gong
- FAFU-UCR Joint Center for Horticultural Biology and Metabolomics, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
| | - Jingzhe Guo
- FAFU-UCR Joint Center for Horticultural Biology and Metabolomics, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
- Center for Plant Cell Biology, Institute of Integrated Genome Biology, and Department of Botany and Plant Sciences, University of California, Riverside, California, United States of America
| | - Hui Li
- Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences, Shanghai, China
- Center for Plant Cell Biology, Institute of Integrated Genome Biology, and Department of Botany and Plant Sciences, University of California, Riverside, California, United States of America
| | - Ruizi Li
- FAFU-UCR Joint Center for Horticultural Biology and Metabolomics, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
| | - Weiman Xing
- Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences, Shanghai, China
| | - Zhenbiao Yang
- FAFU-UCR Joint Center for Horticultural Biology and Metabolomics, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
- Center for Plant Cell Biology, Institute of Integrated Genome Biology, and Department of Botany and Plant Sciences, University of California, Riverside, California, United States of America
| | - Yuefeng Guan
- FAFU-UCR Joint Center for Horticultural Biology and Metabolomics, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
- * E-mail:
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60
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Cameron C, Geitmann A. Cell mechanics of pollen tube growth. Curr Opin Genet Dev 2018; 51:11-17. [PMID: 29602058 DOI: 10.1016/j.gde.2018.03.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 03/03/2018] [Accepted: 03/09/2018] [Indexed: 12/13/2022]
Abstract
The pollen tube features particular traits that can only be understood when integrating cell biological with cell mechanical concepts. Firstly, regular temporal variations in the growth rate are governed by a feedback mechanism thought to involve mechanosensitive ion channels. Secondly, the tube uses invasive growth to penetrate the flower tissues with the aim to transport the male sperm cells to their target. Thirdly, the pollen tube is able to reorient its growth direction upon exposure to a guidance cue; the steering mechanism involves the sophisticated choreography of intracellular transport processes. Sophisticated imaging and micromanipulation techniques have been instrumental for the advancement in characterizing the biomechanical features of this crucial cell in the plant reproductive cycle.
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Affiliation(s)
- Christine Cameron
- Department of Plant Science, McGill University, Macdonald Campus, 21111 Lakeshore Road, Sainte-Anne-de-Bellevue, Québec H9X 3V9, Canada
| | - Anja Geitmann
- Department of Plant Science, McGill University, Macdonald Campus, 21111 Lakeshore Road, Sainte-Anne-de-Bellevue, Québec H9X 3V9, Canada.
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61
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Han B, Yang N, Pu H, Wang T. Quantitative Proteomics and Cytology of Rice Pollen Sterol-Rich Membrane Domains Reveals Pre-established Cell Polarity Cues in Mature Pollen. J Proteome Res 2018; 17:1532-1546. [PMID: 29508613 DOI: 10.1021/acs.jproteome.7b00852] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Bing Han
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ning Yang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hai Pu
- Bruker Daltonics Inc. (China), Beijing 100081, China
| | - Tai Wang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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62
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Wang X, Wang K, Yin G, Liu X, Liu M, Cao N, Duan Y, Gao H, Wang W, Ge W, Wang J, Li R, Guo Y. Pollen-Expressed Leucine-Rich Repeat Extensins Are Essential for Pollen Germination and Growth. PLANT PHYSIOLOGY 2018; 176:1993-2006. [PMID: 29269573 PMCID: PMC5841703 DOI: 10.1104/pp.17.01241] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 12/18/2017] [Indexed: 05/18/2023]
Abstract
During pollen tube growth, the walls of the tube provide the mechanical strength resisting turgor pressure to protect two sperm cells. Cell wall proteins may play an important role in this process. Pollen tube cell wall proteins known as leucine-rich repeat extensins (LRXs) harbor a leucine-rich repeat domain and an extensin domain. In this study, the functions of four pollen-expressed LRXs, LRX8, LRX9, LRX10, and LRX11 (LRX8-11), were characterized in Arabidopsis (Arabidopsis thaliana). LRX8-11 displayed a consistent expression pattern in mature pollen grains and pollen tubes. In a phenotypic analysis of four single mutants, six double mutants, four triple mutants, and a quadruple mutant, the triple and quadruple mutant plants displayed markedly reduced seed set and decreased male transmission efficiency accompanied by compromised pollen germination and pollen tube growth. GFP-fused LRX8, LRX10, and LRX11 were found to be localized to pollen tube cell walls. An immunohistochemical analysis of pollen tube cell wall polysaccharides showed an increase in the amount of rhamnogalacturonan I in the subapical walls of pollen tubes of the lrx9 lrx10 lrx11 and lrx8 lrx9 lrx11 mutants and a decrease in the content of fucosylated xyloglucans in lrx8 lrx9 lrx11 compared with wild-type plants. Moreover, the callose content in the apical walls of pollen tubes increased in the lrx8 lrx9 lrx11 mutant. In conclusion, we propose that LRX8-11 function synergistically to maintain pollen tube cell wall integrity; thus, they play critical roles in pollen germination and pollen tube growth.
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Affiliation(s)
- Xiaoxiao Wang
- Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei 050024, People's Republic of China
- Key Laboratory of Molecular and Cellular Biology of the Ministry of Education, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei 050024, People's Republic of China
- Hebei Collaboration Innovation Center for Cell Signaling, Shijia Zhuang, Hebei 050024, People's Republic of China
| | - Kaiyue Wang
- Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei 050024, People's Republic of China
- Key Laboratory of Molecular and Cellular Biology of the Ministry of Education, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei 050024, People's Republic of China
- Hebei Collaboration Innovation Center for Cell Signaling, Shijia Zhuang, Hebei 050024, People's Republic of China
| | - Guimin Yin
- Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei 050024, People's Republic of China
- Key Laboratory of Molecular and Cellular Biology of the Ministry of Education, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei 050024, People's Republic of China
- Hebei Collaboration Innovation Center for Cell Signaling, Shijia Zhuang, Hebei 050024, People's Republic of China
| | - Xiaoyu Liu
- Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei 050024, People's Republic of China
- Key Laboratory of Molecular and Cellular Biology of the Ministry of Education, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei 050024, People's Republic of China
- Hebei Collaboration Innovation Center for Cell Signaling, Shijia Zhuang, Hebei 050024, People's Republic of China
| | - Mei Liu
- Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei 050024, People's Republic of China
- Key Laboratory of Molecular and Cellular Biology of the Ministry of Education, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei 050024, People's Republic of China
- Hebei Collaboration Innovation Center for Cell Signaling, Shijia Zhuang, Hebei 050024, People's Republic of China
| | - Nana Cao
- Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei 050024, People's Republic of China
- Key Laboratory of Molecular and Cellular Biology of the Ministry of Education, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei 050024, People's Republic of China
- Hebei Collaboration Innovation Center for Cell Signaling, Shijia Zhuang, Hebei 050024, People's Republic of China
| | - Yazhou Duan
- Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei 050024, People's Republic of China
- Key Laboratory of Molecular and Cellular Biology of the Ministry of Education, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei 050024, People's Republic of China
- Hebei Collaboration Innovation Center for Cell Signaling, Shijia Zhuang, Hebei 050024, People's Republic of China
| | - Hui Gao
- Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei 050024, People's Republic of China
- Key Laboratory of Molecular and Cellular Biology of the Ministry of Education, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei 050024, People's Republic of China
- Hebei Collaboration Innovation Center for Cell Signaling, Shijia Zhuang, Hebei 050024, People's Republic of China
| | - Wanlei Wang
- Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei 050024, People's Republic of China
- Key Laboratory of Molecular and Cellular Biology of the Ministry of Education, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei 050024, People's Republic of China
- Hebei Collaboration Innovation Center for Cell Signaling, Shijia Zhuang, Hebei 050024, People's Republic of China
| | - Weina Ge
- Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei 050024, People's Republic of China
- Key Laboratory of Molecular and Cellular Biology of the Ministry of Education, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei 050024, People's Republic of China
- Hebei Collaboration Innovation Center for Cell Signaling, Shijia Zhuang, Hebei 050024, People's Republic of China
| | - Jing Wang
- Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei 050024, People's Republic of China
- Key Laboratory of Molecular and Cellular Biology of the Ministry of Education, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei 050024, People's Republic of China
- Hebei Collaboration Innovation Center for Cell Signaling, Shijia Zhuang, Hebei 050024, People's Republic of China
| | - Rui Li
- Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei 050024, People's Republic of China
- Key Laboratory of Molecular and Cellular Biology of the Ministry of Education, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei 050024, People's Republic of China
- Hebei Collaboration Innovation Center for Cell Signaling, Shijia Zhuang, Hebei 050024, People's Republic of China
| | - Yi Guo
- Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei 050024, People's Republic of China
- Key Laboratory of Molecular and Cellular Biology of the Ministry of Education, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei 050024, People's Republic of China
- Hebei Collaboration Innovation Center for Cell Signaling, Shijia Zhuang, Hebei 050024, People's Republic of China
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Jia H, Yang J, Liesche J, Liu X, Hu Y, Si W, Guo J, Li J. Ethylene promotes pollen tube growth by affecting actin filament organization via the cGMP-dependent pathway in Arabidopsis thaliana. PROTOPLASMA 2018; 255:273-284. [PMID: 28864968 DOI: 10.1007/s00709-017-1158-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 08/23/2017] [Indexed: 06/07/2023]
Abstract
Ethylene and cGMP are key regulators of plant developmental processes. In this study, we demonstrate that ethylene or cGMP promote pollen tube growth in a dose-dependent manner. The etr1-1 mutant was found to be insensitive to ethylene with regard to pollen tube growth, while the growth-promoting effect of ethylene in etr2-2, ein4-4, or ein4-7 did not change, suggesting that ethylene signaling was mainly perceived by ETR1. However, the function of cGMP was not inhibited in etr1-1 and pollen tubes became insensitive to ethylene when the endogenous cGMP level was artificially decreased. This shows that cGMP is necessary for the control of pollen tube growth and that it might be a downstream component of ETR1 in the ethylene signaling pathway. Our study also found that ethylene or cGMP increase the actin bundles and elevated the percentage of relative amount of F-actin, while removal of cGMP decreased actin bundles abundance and altered the ratio of F-actin in the tip and base regions of pollen tubes. In conclusion, our data suggests that ethylene functions as the upstream signal of cGMP, and that both signals promote pollen germination and tube growth by regulating F-actin, which is essential for vesicular transport and cytoplasmic streaming.
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Affiliation(s)
- Honglei Jia
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, China
- School of Environmental Science and Engineering, Shaanxi University of Science & Technology, Xi'an, Shaanxi, 710021, China
| | - Jun Yang
- School of Environmental Science and Engineering, Shaanxi University of Science & Technology, Xi'an, Shaanxi, 710021, China
| | - Johannes Liesche
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Xin Liu
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Yanfeng Hu
- Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Nangang District, Harbin, 150000, China
| | - Wantong Si
- Inner Mongolia Key Laboratory of Biomass-Energy Conversion, Inner Mongolia University of Science and Technology, Neimenggu, Baotou, 014010, China
| | - Junkang Guo
- School of Environmental Science and Engineering, Shaanxi University of Science & Technology, Xi'an, Shaanxi, 710021, China
| | - Jisheng Li
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, China.
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64
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Yu Y, Song J, Tian X, Zhang H, Li L, Zhu H. Arabidopsis PRK6 interacts specifically with AtRopGEF8/12 and induces depolarized growth of pollen tubes when overexpressed. SCIENCE CHINA. LIFE SCIENCES 2018; 61:100-112. [PMID: 28795376 DOI: 10.1007/s11427-016-9107-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2017] [Accepted: 06/02/2017] [Indexed: 11/25/2022]
Abstract
The pollen receptor kinases (PRK) are critical regulators of pollen tube growth. The Arabidopsis genome encodes eight PRK genes, of which six are highly expressed in pollen tubes. The potential functions of AtPRK1 through AtPRK5, but not of AtPRK6, in pollen growth were analyzed in tobacco. Herein, AtPRK6 was cloned, and its function was identified. AtPRK6 was expressed specifically in pollen tubes. A yeast two-hybrid screen of AtPRK6 against 14 Arabidopsis Rop guanine nucleotide exchange factors (RopGEFs) showed that AtPRK6 interacted with AtRopGEF8 and AtRopGEF12. These interactions were confirmed in Arabidopsis mesophyll protoplasts. The interactions between AtPRK6 and AtRopGEF8/12 were mediated by the C-termini of AtRopGEF8/12 and by the juxtamembrane and kinase domain of AtPRK6, but were not dependent on the kinase activity. In addition, transient overexpression of AtPRK6::GFP in Arabidopsis protoplasts revealed that AtPRK6 was localized to the plasma membrane. Tobacco pollen tubes overexpressing AtPRK6 exhibited shorter tubes with enlarged tips. This depolarized tube growth required the kinase domain of AtPRK6 and was not dependent on kinase activity. Taken together, the results show that AtPRK6, through its juxtamembrane and kinase domains (KD), interacts with AtRopGEF8/12 and plays crucial roles in polarized growth of pollen tubes.
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Affiliation(s)
- Yuexuan Yu
- College of Life Sciences, Capital Normal University, Beijing, 100048, China
| | - Jiali Song
- College of Life Sciences, Capital Normal University, Beijing, 100048, China
| | - Xiaohui Tian
- College of Life Sciences, Capital Normal University, Beijing, 100048, China
| | - Haiwen Zhang
- College of Life Sciences, Capital Normal University, Beijing, 100048, China
| | - Legong Li
- College of Life Sciences, Capital Normal University, Beijing, 100048, China
| | - Huifen Zhu
- College of Life Sciences, Capital Normal University, Beijing, 100048, China.
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65
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Moeder W, Yoshioka K. CNGCs break through-A rice cyclic nucleotide-gated channel paves the way for pollen tube growth. PLoS Genet 2017; 13:e1007066. [PMID: 29190294 PMCID: PMC5708612 DOI: 10.1371/journal.pgen.1007066] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Affiliation(s)
- Wolfgang Moeder
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Keiko Yoshioka
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
- Center for the Analysis of Genome Evolution and Function (CAGEF), University of Toronto, Toronto, Ontario, Canada
- * E-mail:
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66
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Su H, Feng H, Chao X, Ding X, Nan Q, Wen C, Liu H, Xiang Y, Liu W. Fimbrins 4 and 5 Act Synergistically During Polarized Pollen Tube Growth to Ensure Fertility in Arabidopsis. PLANT & CELL PHYSIOLOGY 2017; 58:2006-2016. [PMID: 29036437 DOI: 10.1093/pcp/pcx138] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2017] [Accepted: 09/03/2017] [Indexed: 06/07/2023]
Abstract
The germination and polar growth of pollen are prerequisite for double fertilization in plants. The actin cytoskeleton and its binding proteins play pivotal roles in pollen germination and pollen tube growth. Two homologs of the actin-bundling protein fimbrin, AtFIM4 and AtFIM5, are highly expressed in pollen in Arabidopsis and can form distinct actin architectures in vitro, but how they co-operatively regulate pollen germination and pollen tube growth in vivo is largely unknown. In this study, we explored their functions during pollen germination and polar growth. Histochemical analysis demonstrated that AtFIM4 was expressed only after pollen grain hydration and, in the early stage of pollen tube growth, the expression level of AtFIM4 was low, indicating that it functions mainly during polarized tube growth, whereas AtFIM5 had high expression levels in both pollen grains and pollen tubes. Atfim4/atfim5 double mutant plants had fertility defects including reduced silique length and seed number, which were caused by severe defects in pollen germination and pollen tube growth. When the atfim4/atfim5 double mutant was complemented with the AtFIM5 protein, the polar growth of pollen tubes was fully rescued; however, AtFIM4 could only partially restore these defects. Fluorescence labeling showed that loss of function of both AtFIM4 and AtFIM5 decreased the extent of actin filament bundling throughout pollen tubes. Collectively, our results revealed that AtFIM4 acts co-ordinately with AtFIM5 to organize and maintain normal actin architecture in pollen grains and pollen tubes to fulfill double fertilization in plants.
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Affiliation(s)
- Hui Su
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, School of Life Sciences, Northwest University, Xi'an 710069, China
| | - Hualing Feng
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, School of Life Sciences, Northwest University, Xi'an 710069, China
| | - Xiaoting Chao
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, School of Life Sciences, Northwest University, Xi'an 710069, China
| | - Xia Ding
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, School of Life Sciences, Northwest University, Xi'an 710069, China
| | - Qiong Nan
- Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Chenxi Wen
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, School of Life Sciences, Northwest University, Xi'an 710069, China
| | | | - Yun Xiang
- Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Wenzhe Liu
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, School of Life Sciences, Northwest University, Xi'an 710069, China
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Zhu J, Nan Q, Qin T, Qian D, Mao T, Yuan S, Wu X, Niu Y, Bai Q, An L, Xiang Y. Higher-Ordered Actin Structures Remodeled by Arabidopsis ACTIN-DEPOLYMERIZING FACTOR5 Are Important for Pollen Germination and Pollen Tube Growth. MOLECULAR PLANT 2017; 10:1065-1081. [PMID: 28606871 DOI: 10.1016/j.molp.2017.06.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 06/02/2017] [Accepted: 06/05/2017] [Indexed: 06/07/2023]
Abstract
Dynamics of the actin cytoskeleton are essential for pollen germination and pollen tube growth. ACTIN-DEPOLYMERIZING FACTORs (ADFs) typically contribute to actin turnover by severing/depolymerizing actin filaments. Recently, we demonstrated that Arabidopsis subclass III ADFs (ADF5 and ADF9) evolved F-actin-bundling function from conserved F-actin-depolymerizing function. However, little is known about the physiological function, the evolutional significance, and the actin-bundling mechanism of these neofunctionalized ADFs. Here, we report that loss of ADF5 function caused delayed pollen germination, retarded pollen tube growth, and increased sensitive to latrunculin B (LatB) treatment by affecting the generation and maintenance of actin bundles. Examination of actin filament dynamics in living cells revealed that the bundling frequency was significantly decreased in adf5 pollen tubes, consistent with its biochemical functions. Further biochemical and genetic complementation analyses demonstrated that both the N- and C-terminal actin-binding domains of ADF5 are required for its physiological and biochemical functions. Interestingly, while both are atypical actin-bundling ADFs, ADF5, but not ADF9, plays an important role in mature pollen physiological activities. Taken together, our results suggest that ADF5 has evolved the function of bundling actin filaments and plays an important role in the formation, organization, and maintenance of actin bundles during pollen germination and pollen tube growth.
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Affiliation(s)
- Jingen Zhu
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Qiong Nan
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Tao Qin
- State Key Laboratory of Plant Physiology and Biochemistry, Department of Plant Sciences, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Dong Qian
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Tonglin Mao
- State Key Laboratory of Plant Physiology and Biochemistry, Department of Plant Sciences, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Shunjie Yuan
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Xiaorong Wu
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Yue Niu
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Qifeng Bai
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Lizhe An
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Yun Xiang
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China.
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Xu Y, Yang J, Wang Y, Wang J, Yu Y, Long Y, Wang Y, Zhang H, Ren Y, Chen J, Wang Y, Zhang X, Guo X, Wu F, Zhu S, Lin Q, Jiang L, Wu C, Wang H, Wan J. OsCNGC13 promotes seed-setting rate by facilitating pollen tube growth in stylar tissues. PLoS Genet 2017; 13:e1006906. [PMID: 28708858 PMCID: PMC5533464 DOI: 10.1371/journal.pgen.1006906] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 07/28/2017] [Accepted: 07/05/2017] [Indexed: 11/29/2022] Open
Abstract
Seed-setting rate is a critical determinant of grain yield in rice (Oryza sativa L.). Rapid and healthy pollen tube growth in the style is required for high seed-setting rate. The molecular mechanisms governing this process remain largely unknown. In this study, we isolate a dominant low seed-setting rate rice mutant, sss1-D. Cellular examination results show that pollen tube growth is blocked in about half of the mutant styles. Molecular cloning and functional assays reveals that SSS1-D encodes OsCNGC13, a member of the cyclic nucleotide-gated channel family. OsCNGC13 is preferentially expressed in the pistils and its expression is dramatically reduced in the heterozygous plant, suggesting a haploinsufficiency nature for the dominant mutant phenotype. We show that OsCNGC13 is permeable to Ca2+. Consistent with this, accumulation of cytoplasmic calcium concentration ([Ca2+]cyt) is defective in the sss1-D mutant style after pollination. Further, the sss1-D mutant has altered extracellular matrix (ECM) components and delayed cell death in the style transmission tract (STT). Based on these results, we propose that OsCNGC13 acts as a novel maternal sporophytic factor required for stylar [Ca2+]cyt accumulation, ECM components modification and STT cell death, thus facilitating the penetration of pollen tube in the style for successful double fertilization and seed-setting in rice. Rice is not only the staple food for more than half of the world’s population, but also a model species for plant developmental and genetic studies. After pollination, rice pollen grains adhere and hydrate at the surface of stigmatic papilla cells. Then, the germinated pollen tubes invade the stigma and navigate through the style transmission tract to reach the micropyle of the embryo sac for fertilization. During this long and arduous process, pollen tube requires abundant communication with the surrounding sporophytic maternal tissues. However, how the growth of pollen tube is regulated by maternal tissue remains largely elusive. This work identifies a typical cyclic nucleotide-gated channel protein in rice, OsCNGC13, which can mediate Ca2+ inward current. Our results suggest that OsCNGC13 acts as a novel maternal sporophytic factor required for stylar [Ca2+]cyt accumulation, extracellular matrix components modification and style cell death, thus facilitating the penetration of pollen tube in the style for successful double fertilization and seed-setting in rice. These findings provide new insights into the molecular genetic control mechanisms of seed-setting rate/grain yield in rice and expand our knowledge on the cyclic nucleotide-gated channel proteins in plant sexual reproduction.
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Affiliation(s)
- Yang Xu
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jie Yang
- Institute of Food Crops, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Yihua Wang
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
| | - Jiachang Wang
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
| | - Yang Yu
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
| | - Yu Long
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, National Plant Gene Research Centre (Beijing), China Agricultural University, Beijing, China
| | - Yunlong Wang
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
| | - Huan Zhang
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
| | - Yulong Ren
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jun Chen
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Ying Wang
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xin Zhang
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xiuping Guo
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Fuqing Wu
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Shanshan Zhu
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Qibing Lin
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Ling Jiang
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
| | - Chuanyin Wu
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Haiyang Wang
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jianmin Wan
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China
- * E-mail:
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69
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Qu X, Zhang R, Zhang M, Diao M, Xue Y, Huang S. Organizational Innovation of Apical Actin Filaments Drives Rapid Pollen Tube Growth and Turning. MOLECULAR PLANT 2017; 10:930-947. [PMID: 28502709 DOI: 10.1016/j.molp.2017.05.002] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 04/15/2017] [Accepted: 05/01/2017] [Indexed: 06/07/2023]
Abstract
Polarized tip growth is a fundamental cellular process in many eukaryotes. In this study, we examined the dynamic restructuring of the actin cytoskeleton and its relationship to vesicle transport during pollen tip growth in Arabidopsis. We found that actin filaments originating from the apical membrane form a specialized structure consisting of longitudinally aligned actin bundles at the cortex and inner cytoplasmic filaments with a distinct distribution. Using actin-based pharmacological treatments and genetic mutants in combination with FRAP (fluorescence recovery after photobleaching) technology to visualize the transport of vesicles within the growth domain of pollen tubes, we demonstrated that cortical actin filaments facilitate tip-ward vesicle transport. We also discovered that the inner apical actin filaments prevent backward movement of vesicles, thus ensuring that sufficient vesicles accumulate at the pollen tube tip to support the rapid growth of the pollen tube. The combinatorial effect of cortical and internal apical actin filaments perfectly explains the generation of the inverted "V" cone-shaped vesicle distribution pattern at the pollen tube tip. When pollen tubes turn, apical actin filaments at the facing side undergo depolymerization and repolymerization to reorient the apical actin structure toward the new growth direction. This actin restructuring precedes vesicle accumulation and changes in tube morphology. Thus, our study provides new insights into the functional relationship between actin dynamics and vesicle transport during rapid and directional pollen tube growth.
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Affiliation(s)
- Xiaolu Qu
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Ruihui Zhang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Meng Zhang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China; Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Min Diao
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China; Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Yongbiao Xue
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101, China
| | - Shanjin Huang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China; Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
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Suwińska A, Wasąg P, Zakrzewski P, Lenartowska M, Lenartowski R. Calreticulin is required for calcium homeostasis and proper pollen tube tip growth in Petunia. PLANTA 2017; 245:909-926. [PMID: 28078426 PMCID: PMC5391374 DOI: 10.1007/s00425-017-2649-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 01/05/2017] [Indexed: 05/19/2023]
Abstract
MAIN CONCLUSION Calreticulin is involved in stabilization of the tip-focused Ca 2+ gradient and the actin cytoskeleton arrangement and function that is required for several key processes driving Petunia pollen tube tip growth. Although the precise mechanism is unclear, stabilization of a tip-focused calcium (Ca2+) gradient seems to be critical for pollen germination and pollen tube growth. We hypothesize that calreticulin (CRT), a Ca2+-binding/buffering chaperone typically residing in the lumen of the endoplasmic reticulum (ER) of eukaryotic cells, is an excellent candidate to fulfill this role. We previously showed that in Petunia pollen tubes growing in vitro, CRT is translated on ER membrane-bound ribosomes that are abundant in the subapical zone of the tube, where CRT's Ca2+-buffering and chaperone activities might be particularly required. Here, we sought to determine the function of CRT using small interfering RNA (siRNA) to, for the first time in pollen tubes growing in vitro, knockdown expression of a gene. We demonstrate that siRNA-mediated post-transcriptional silencing of Petunia hybrida CRT gene (PhCRT) expression strongly impairs pollen tube growth, cytoplasmic zonation, actin cytoskeleton organization, and the tip-focused Ca2+ gradient. Moreover, reduction of CRT alters the localization and disturbs the structure of the ER in abnormally elongating pollen tubes. Finally, cytoplasmic streaming is inhibited, and most of the pollen tubes rupture. Our data clearly show an interplay between CRT, Ca2+ gradient, actin-dependent cytoplasmic streaming, organelle positioning, and vesicle trafficking during pollen tube elongation. Thus, we suggest that CRT functions in Petunia pollen tube growth by stabilizing Ca2+ homeostasis and acting as a chaperone to assure quality control of glycoproteins passing through the ER.
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Affiliation(s)
- Anna Suwińska
- Laboratory of Developmental Biology, Faculty of Biology and Environmental Protection, Nicolaus Copernicus University in Toruń, Toruń, Poland
| | - Piotr Wasąg
- Laboratory of Isotope and Instrumental Analysis, Faculty of Biology and Environmental Protection, Nicolaus Copernicus University in Toruń, Toruń, Poland
| | - Przemysław Zakrzewski
- Laboratory of Developmental Biology, Faculty of Biology and Environmental Protection, Nicolaus Copernicus University in Toruń, Toruń, Poland
| | - Marta Lenartowska
- Laboratory of Developmental Biology, Faculty of Biology and Environmental Protection, Nicolaus Copernicus University in Toruń, Toruń, Poland
| | - Robert Lenartowski
- Laboratory of Isotope and Instrumental Analysis, Faculty of Biology and Environmental Protection, Nicolaus Copernicus University in Toruń, Toruń, Poland.
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Hu C, Vogler H, Aellen M, Shamsudhin N, Jang B, Burri JT, Läubli N, Grossniklaus U, Pané S, Nelson BJ. High precision, localized proton gradients and fluxes generated by a microelectrode device induce differential growth behaviors of pollen tubes. LAB ON A CHIP 2017; 17:671-680. [PMID: 28098283 DOI: 10.1039/c6lc01307d] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Pollen tubes are tip-growing plant cells that deliver the sperm cells to the ovules for double fertilization of the egg cell and the endosperm. Various directional cues can trigger the reorientation of pollen tube growth direction on their passage through the female tissues. Among the external stimuli, protons serve an important, regulatory role in the control of pollen tube growth. The generation of local guidance cues has been challenging when investigating the mechanisms of perception and processing of such directional triggers in pollen tubes. Here, we developed and characterized a microelectrode device to generate a local proton gradient and proton flux through water electrolysis. We confirmed that the cytoplasmic pH of pollen tubes varied with environmental pH change. Depending on the position of the pollen tube tip relative to the proton gradient, we observed alterations in the growth behavior, such as bursting at the tip, change in growth direction, or complete growth arrest. Bursting and growth arrest support the hypothesis that changes in the extracellular H+ concentration may interfere with cell wall integrity and actin polymerization at the growing tip. A change in growth direction for some pollen tubes implies that they can perceive the local proton gradient and respond to it. We also showed that the growth rate is directly correlated with the extracellular pH in the tip region. Our microelectrode approach provides a simple method to generate protons and investigate their effect on plant cell growth.
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Affiliation(s)
- Chengzhi Hu
- Institute of Robotics and Intelligent Systems, ETH Zurich, Tannenstrasse 3, CH-8092 Zurich, Switzerland.
| | - Hannes Vogler
- Department of Plant and Microbial Biology & Zurich-Basel Plant Science Center, University of Zurich, Zollikerstrasse 107, CH-8008 Zurich, Switzerland
| | - Marianne Aellen
- Institute of Robotics and Intelligent Systems, ETH Zurich, Tannenstrasse 3, CH-8092 Zurich, Switzerland.
| | - Naveen Shamsudhin
- Institute of Robotics and Intelligent Systems, ETH Zurich, Tannenstrasse 3, CH-8092 Zurich, Switzerland.
| | - Bumjin Jang
- Institute of Robotics and Intelligent Systems, ETH Zurich, Tannenstrasse 3, CH-8092 Zurich, Switzerland.
| | - Jan T Burri
- Institute of Robotics and Intelligent Systems, ETH Zurich, Tannenstrasse 3, CH-8092 Zurich, Switzerland.
| | - Nino Läubli
- Institute of Robotics and Intelligent Systems, ETH Zurich, Tannenstrasse 3, CH-8092 Zurich, Switzerland.
| | - Ueli Grossniklaus
- Department of Plant and Microbial Biology & Zurich-Basel Plant Science Center, University of Zurich, Zollikerstrasse 107, CH-8008 Zurich, Switzerland
| | - Salvador Pané
- Institute of Robotics and Intelligent Systems, ETH Zurich, Tannenstrasse 3, CH-8092 Zurich, Switzerland.
| | - Bradley J Nelson
- Institute of Robotics and Intelligent Systems, ETH Zurich, Tannenstrasse 3, CH-8092 Zurich, Switzerland.
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Ye ZW, Xu J, Shi J, Zhang D, Chye ML. Kelch-motif containing acyl-CoA binding proteins AtACBP4 and AtACBP5 are differentially expressed and function in floral lipid metabolism. PLANT MOLECULAR BIOLOGY 2017; 93:209-225. [PMID: 27826761 DOI: 10.1007/s11103-016-0557-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 10/30/2016] [Indexed: 05/14/2023]
Abstract
We herein demonstrated two of the Arabidopsis acyl-CoA-binding proteins (ACBPs), AtACBP4 and AtACBP5, both function in floral lipid metabolism and they may possibly play complementary roles in Arabidopsis microspore-to-pollen development. Histological analysis on transgenic Arabidopsis expressing β-glucuronidase driven from the AtACBP4 and AtACBP5 promoters, as well as, qRTPCR analysis revealed that AtACBP4 was expressed at stages 11-14 in the mature pollen, while AtACBP5 was expressed at stages 7-10 in the microspores and tapetal cells. Immunoelectron microscopy using AtACBP4- or AtACBP5-specific antibodies further showed that AtACBP4 and AtACBP5 were localized in the cytoplasm. Chemical analysis of bud wax and cutin using gas chromatographyflame ionization detector and GC-mass spectrometry analyses revealed the accumulation of cuticular waxes and cutin monomers in acbp4, acbp5 and acbp4acbp5 buds in comparison to the wild type (Col-0). Fatty acid profiling demonstrated a decline in stearic acid and an increase in linolenic acid in acbp4 and acbp4acbp5 buds, respectively, over Col-0. Analysis of inflorescences from acbp4 and acbp5 revealed that there was an increase of AtACBP5 expression in acbp4, and an increase of AtACBP4 expression in acbp5. Deletion analysis of the AtACBP4 and AtACBP5 5'-flanking regions indicated the minimal promoter activity for AtACBP4 (-145/+103) and AtACBP5 (-181/+81). Electrophoretic mobility shift assays identified a pollen-specific cis-acting element POLLEN1 (AGAAA) mapped at AtACBP4 (-157/-153) which interacted with nuclear proteins from flower and this was substantiated by DNase I footprinting. In Arabidopsis thaliana, six acyl-CoA-binding proteins (ACBPs), designated as AtACBP1 to AtACBP6, have been identified to function in plant stress and development. AtACBP4 and AtACBP5 represent the two largest proteins in the AtACBP family. Despite having kelch-motifs and sharing a common cytosolic subcellular localization, AtACBP4 and AtACBP5 differ in spatial and temporal expression. Histological analysis on transgenic Arabidopsis expressing β-glucuronidase driven from the respective AtACBP4 and AtACBP5 promoters, as well as, qRT-PCR analysis revealed that AtACBP4 was expressed at stages 11-14 in mature pollen, while AtACBP5 was expressed at stages 7-10 in the microspores and tapetal cells. Immunoelectron microscopy using AtACBP4- or AtACBP5-specific antibodies further showed that AtACBP4 and AtACBP5 were localized in the cytoplasm. Chemical analysis of bud wax and cutin using gas chromatography-flame ionization detector and GC-mass spectrometry analyses revealed the accumulation of cuticular waxes and cutin monomers in acbp4, acbp5 and acbp4acbp5 buds, in comparison to the wild type. Analysis of inflorescences from acbp4 and acbp5 revealed that there was an increase of AtACBP5 expression in acbp4, and an increase of AtACBP4 expression in acbp5. Deletion analysis of the AtACBP4 and AtACBP5 5'-flanking regions indicated the minimal promoter region for AtACBP4 (-145/+103) and AtACBP5 (-181/+81). Electrophoretic mobility shift assays identified a pollen-specific cis-acting element POLLEN1 (AGAAA) within AtACBP4 (-157/-153) which interacted with nuclear proteins from flower and this was substantiated by DNase I footprinting. These results suggest that AtACBP4 and AtACBP5 both function in floral lipidic metabolism and they may play complementary roles in Arabidopsis microspore-to-pollen development.
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Affiliation(s)
- Zi-Wei Ye
- School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Jie Xu
- Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Jianxin Shi
- Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Dabing Zhang
- Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Mee-Len Chye
- School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China.
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Abstract
Underlying rapid and directional pollen tube growth is the active intracellular trafficking system that carries materials necessary for cell wall synthesis and membrane expansion to the expanding point of the pollen tube. The actin cytoskeleton has been shown to control various intracellular trafficking events in the pollen tube, but the underlying cellular and molecular mechanisms remain poorly understood. To better understand how the actin cytoskeleton is involved in the regulation of intracellular trafficking events, we need to establish assays to visualize and quantify the distribution and dynamics of organelles, vesicles, or secreted proteins. In this chapter, we introduce methods regarding the visualization and quantification of the distribution and dynamics of organelles or vesicles in pollen tubes.
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75
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Pérez Di Giorgio JA, Soto GC, Muschietti JP, Amodeo G. Pollen Aquaporins: The Solute Factor. FRONTIERS IN PLANT SCIENCE 2016; 7:1659. [PMID: 27881985 PMCID: PMC5101680 DOI: 10.3389/fpls.2016.01659] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 10/21/2016] [Indexed: 05/12/2023]
Abstract
In the recent years, the biophysical properties and presumed physiological role of aquaporins (AQPs) have been expanded to specialized cells where water and solute exchange are crucial traits. Complex but unique processes such as stomatal movement or pollen hydration and germination have been addressed not only by identifying the specific AQP involved but also by studying how these proteins integrate and coordinate cellular activities and functions. In this review, we referred specifically to pollen-specific AQPs and analyzed what has been assumed in terms of transport properties and what has been found in terms of their physiological role. Unlike that in many other cells, the AQP machinery in mature pollen lacks plasma membrane intrinsic proteins, which are extensively studied for their high water capacity exchange. Instead, a variety of TIPs and NIPs are expressed in pollen. These findings have altered the initial understanding of AQPs and water exchange to consider specific and diverse solutes that might be critical to sustaining pollen's success. The spatial and temporal distribution of the pollen AQPs also reflects a regulatory mechanism that allowing a properly adjusting water and solute exchange.
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Affiliation(s)
- Juliana A. Pérez Di Giorgio
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular – Consejo Nacional de Investigaciones Científicas y TécnicasBuenos Aires, Argentina
| | - Gabriela C. Soto
- Instituto de Genética Ewald A. Favret – Centro de Investigación en Ciencias Veterinarias y Agronómicas – Instituto Nacional de Tecnología Agropecuaria – Consejo Nacional de Investigaciones Científicas y TécnicasBuenos Aires, Argentina
| | - Jorge P. Muschietti
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular – Consejo Nacional de Investigaciones Científicas y TécnicasBuenos Aires, Argentina
- Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos AiresBuenos Aires, Argentina
| | - Gabriela Amodeo
- Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos AiresBuenos Aires, Argentina
- Instituto de Biodiversidad y Biología Experimental y Aplicada – Universidad de Buenos Aires–Consejo Nacional de Investigaciones Científicas y TécnicasBuenos Aires, Argentina
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Bloch D, Pleskot R, Pejchar P, Potocký M, Trpkošová P, Cwiklik L, Vukašinović N, Sternberg H, Yalovsky S, Žárský V. Exocyst SEC3 and Phosphoinositides Define Sites of Exocytosis in Pollen Tube Initiation and Growth. PLANT PHYSIOLOGY 2016; 172:980-1002. [PMID: 27516531 PMCID: PMC5047084 DOI: 10.1104/pp.16.00690] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 08/08/2016] [Indexed: 05/16/2023]
Abstract
Polarized exocytosis is critical for pollen tube growth, but its localization and function are still under debate. The exocyst vesicle-tethering complex functions in polarized exocytosis. Here, we show that a sec3a exocyst subunit null mutant cannot be transmitted through the male gametophyte due to a defect in pollen tube growth. The green fluorescent protein (GFP)-SEC3a fusion protein is functional and accumulates at or proximal to the pollen tube tip plasma membrane. Partial complementation of sec3a resulted in the development of pollen with multiple tips, indicating that SEC3 is required to determine the site of pollen germination pore formation. Time-lapse imaging demonstrated that SEC3a and SEC8 were highly dynamic and that SEC3a localization on the apical plasma membrane predicts the direction of growth. At the tip, polar SEC3a domains coincided with cell wall deposition. Labeling of GFP-SEC3a-expressing pollen with the endocytic marker FM4-64 revealed the presence of subdomains on the apical membrane characterized by extensive exocytosis. In steady-state growing tobacco (Nicotiana tabacum) pollen tubes, SEC3a displayed amino-terminal Pleckstrin homology-like domain (SEC3a-N)-dependent subapical membrane localization. In agreement, SEC3a-N interacted with phosphoinositides in vitro and colocalized with a phosphatidylinositol 4,5-bisphosphate (PIP2) marker in pollen tubes. Correspondingly, molecular dynamics simulations indicated that SEC3a-N associates with the membrane by interacting with PIP2 However, the interaction with PIP2 is not required for polar localization and the function of SEC3a in Arabidopsis (Arabidopsis thaliana). Taken together, our findings indicate that SEC3a is a critical determinant of polar exocytosis during tip growth and suggest differential regulation of the exocytotic machinery depending on pollen tube growth modes.
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Affiliation(s)
- Daria Bloch
- Department of Molecular Biology and Ecology of Plants, Tel Aviv University, Tel Aviv 69978, Israel (D.B., H.S., S.Y.);Institute of Experimental Botany, Czech Academy of Sciences, 165 02 Prague, Czech Republic (R.P., P.P., M.P., P.T., N.V., V.Ž.);J. Heyrovsky Institute of Physical Chemistry, Czech Academy of Sciences, 182 23 Prague, Czech Republic (L.C.); andDepartment of Experimental Plant Biology, Faculty of Science, Charles University, 128 44 Prague, Czech Republic (N.V., V.Ž.)
| | - Roman Pleskot
- Department of Molecular Biology and Ecology of Plants, Tel Aviv University, Tel Aviv 69978, Israel (D.B., H.S., S.Y.);Institute of Experimental Botany, Czech Academy of Sciences, 165 02 Prague, Czech Republic (R.P., P.P., M.P., P.T., N.V., V.Ž.);J. Heyrovsky Institute of Physical Chemistry, Czech Academy of Sciences, 182 23 Prague, Czech Republic (L.C.); andDepartment of Experimental Plant Biology, Faculty of Science, Charles University, 128 44 Prague, Czech Republic (N.V., V.Ž.)
| | - Přemysl Pejchar
- Department of Molecular Biology and Ecology of Plants, Tel Aviv University, Tel Aviv 69978, Israel (D.B., H.S., S.Y.);Institute of Experimental Botany, Czech Academy of Sciences, 165 02 Prague, Czech Republic (R.P., P.P., M.P., P.T., N.V., V.Ž.);J. Heyrovsky Institute of Physical Chemistry, Czech Academy of Sciences, 182 23 Prague, Czech Republic (L.C.); andDepartment of Experimental Plant Biology, Faculty of Science, Charles University, 128 44 Prague, Czech Republic (N.V., V.Ž.)
| | - Martin Potocký
- Department of Molecular Biology and Ecology of Plants, Tel Aviv University, Tel Aviv 69978, Israel (D.B., H.S., S.Y.);Institute of Experimental Botany, Czech Academy of Sciences, 165 02 Prague, Czech Republic (R.P., P.P., M.P., P.T., N.V., V.Ž.);J. Heyrovsky Institute of Physical Chemistry, Czech Academy of Sciences, 182 23 Prague, Czech Republic (L.C.); andDepartment of Experimental Plant Biology, Faculty of Science, Charles University, 128 44 Prague, Czech Republic (N.V., V.Ž.)
| | - Pavlína Trpkošová
- Department of Molecular Biology and Ecology of Plants, Tel Aviv University, Tel Aviv 69978, Israel (D.B., H.S., S.Y.);Institute of Experimental Botany, Czech Academy of Sciences, 165 02 Prague, Czech Republic (R.P., P.P., M.P., P.T., N.V., V.Ž.);J. Heyrovsky Institute of Physical Chemistry, Czech Academy of Sciences, 182 23 Prague, Czech Republic (L.C.); andDepartment of Experimental Plant Biology, Faculty of Science, Charles University, 128 44 Prague, Czech Republic (N.V., V.Ž.)
| | - Lukasz Cwiklik
- Department of Molecular Biology and Ecology of Plants, Tel Aviv University, Tel Aviv 69978, Israel (D.B., H.S., S.Y.);Institute of Experimental Botany, Czech Academy of Sciences, 165 02 Prague, Czech Republic (R.P., P.P., M.P., P.T., N.V., V.Ž.);J. Heyrovsky Institute of Physical Chemistry, Czech Academy of Sciences, 182 23 Prague, Czech Republic (L.C.); andDepartment of Experimental Plant Biology, Faculty of Science, Charles University, 128 44 Prague, Czech Republic (N.V., V.Ž.)
| | - Nemanja Vukašinović
- Department of Molecular Biology and Ecology of Plants, Tel Aviv University, Tel Aviv 69978, Israel (D.B., H.S., S.Y.);Institute of Experimental Botany, Czech Academy of Sciences, 165 02 Prague, Czech Republic (R.P., P.P., M.P., P.T., N.V., V.Ž.);J. Heyrovsky Institute of Physical Chemistry, Czech Academy of Sciences, 182 23 Prague, Czech Republic (L.C.); andDepartment of Experimental Plant Biology, Faculty of Science, Charles University, 128 44 Prague, Czech Republic (N.V., V.Ž.)
| | - Hasana Sternberg
- Department of Molecular Biology and Ecology of Plants, Tel Aviv University, Tel Aviv 69978, Israel (D.B., H.S., S.Y.);Institute of Experimental Botany, Czech Academy of Sciences, 165 02 Prague, Czech Republic (R.P., P.P., M.P., P.T., N.V., V.Ž.);J. Heyrovsky Institute of Physical Chemistry, Czech Academy of Sciences, 182 23 Prague, Czech Republic (L.C.); andDepartment of Experimental Plant Biology, Faculty of Science, Charles University, 128 44 Prague, Czech Republic (N.V., V.Ž.)
| | - Shaul Yalovsky
- Department of Molecular Biology and Ecology of Plants, Tel Aviv University, Tel Aviv 69978, Israel (D.B., H.S., S.Y.);Institute of Experimental Botany, Czech Academy of Sciences, 165 02 Prague, Czech Republic (R.P., P.P., M.P., P.T., N.V., V.Ž.);J. Heyrovsky Institute of Physical Chemistry, Czech Academy of Sciences, 182 23 Prague, Czech Republic (L.C.); andDepartment of Experimental Plant Biology, Faculty of Science, Charles University, 128 44 Prague, Czech Republic (N.V., V.Ž.)
| | - Viktor Žárský
- Department of Molecular Biology and Ecology of Plants, Tel Aviv University, Tel Aviv 69978, Israel (D.B., H.S., S.Y.);Institute of Experimental Botany, Czech Academy of Sciences, 165 02 Prague, Czech Republic (R.P., P.P., M.P., P.T., N.V., V.Ž.);J. Heyrovsky Institute of Physical Chemistry, Czech Academy of Sciences, 182 23 Prague, Czech Republic (L.C.); andDepartment of Experimental Plant Biology, Faculty of Science, Charles University, 128 44 Prague, Czech Republic (N.V., V.Ž.)
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Dou XY, Yang KZ, Ma ZX, Chen LQ, Zhang XQ, Bai JR, Ye D. AtTMEM18 plays important roles in pollen tube and vegetative growth in Arabidopsis. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2016; 58:679-92. [PMID: 26699939 PMCID: PMC5067611 DOI: 10.1111/jipb.12459] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 12/21/2015] [Indexed: 05/06/2023]
Abstract
In flowering plants, pollen tube growth is essential for delivery of male gametes into the female gametophyte or embryo sac for double fertilization. Although many genes have been identified as being involved in the process, the molecular mechanisms of pollen tube growth remains poorly understood. In this study, we identified that the Arabidopsis Transmembrane Protein 18 (AtTMEM18) gene played important roles in pollen tube growth. The AtTMEM18 shares a high similarity with the Transmembrane 18 proteins (TMEM18s) that are conserved in most eukaryotes and may play important roles in obesity in humans. Mutation in the AtTMEM18 by a Ds insertion caused abnormal callose deposition in the pollen grains and had a significant impact on pollen germination and pollen tube growth. AtTMEM18 is expressed in pollen grains, pollen tubes, root tips and other vegetative tissues. The pollen-rescued assays showed that the mutation in AtTMEM18 also caused defects in roots, stems, leaves and transmitting tracts. AtTMEM18-GFP was located around the nuclei. Genetic assays demonstrated that the localization of AtTMEM18 around the nuclei in the generative cells of pollen grains was essential for the male fertility. Furthermore, expression of the rice TMEM18-homologous protein (OsTMEM18) driven by LAT52 promoter could recover the fertility of the Arabidopsis attmem18 mutant. These results suggested that the TMEM18 is important for plant growth in Arabidopsis.
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Affiliation(s)
- Xiao-Ying Dou
- Beijing Radiation Center, 12 Haidian Nanlu, Beijing 100875, China
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, 2 Yuanmingyuan Xilu, Beijing 100193, China
| | - Ke-Zhen Yang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, 2 Yuanmingyuan Xilu, Beijing 100193, China
| | - Zhao-Xia Ma
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, 2 Yuanmingyuan Xilu, Beijing 100193, China
| | - Li-Qun Chen
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, 2 Yuanmingyuan Xilu, Beijing 100193, China
| | - Xue-Qin Zhang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, 2 Yuanmingyuan Xilu, Beijing 100193, China
| | - Jin-Rong Bai
- Beijing Radiation Center, 12 Haidian Nanlu, Beijing 100875, China
| | - De Ye
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, 2 Yuanmingyuan Xilu, Beijing 100193, China
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78
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Nieves-Cordones M, Al Shiblawi FR, Sentenac H. Roles and Transport of Sodium and Potassium in Plants. Met Ions Life Sci 2016; 16:291-324. [PMID: 26860305 DOI: 10.1007/978-3-319-21756-7_9] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The two alkali cations Na(+) and K(+) have similar relative abundances in the earth crust but display very different distributions in the biosphere. In all living organisms, K(+) is the major inorganic cation in the cytoplasm, where its concentration (ca. 0.1 M) is usually several times higher than that of Na(+). Accumulation of Na(+) at high concentrations in the cytoplasm results in deleterious effects on cell metabolism, e.g., on photosynthetic activity in plants. Thus, Na(+) is compartmentalized outside the cytoplasm. In plants, it can be accumulated at high concentrations in vacuoles, where it is used as osmoticum. Na(+) is not an essential element in most plants, except in some halophytes. On the other hand, it can be a beneficial element, by replacing K(+) as vacuolar osmoticum for instance. In contrast, K(+) is an essential element. It is involved in electrical neutralization of inorganic and organic anions and macromolecules, pH homeostasis, control of membrane electrical potential, and the regulation of cell osmotic pressure. Through the latter function in plants, it plays a role in turgor-driven cell and organ movements. It is also involved in the activation of enzymes, protein synthesis, cell metabolism, and photosynthesis. Thus, plant growth requires large quantities of K(+) ions that are taken up by roots from the soil solution, and then distributed throughout the plant. The availability of K(+) ions in the soil solution, slowly released by soil particles and clays, is often limiting for optimal growth in most natural ecosystems. In contrast, due to natural salinity or irrigation with poor quality water, detrimental Na(+) concentrations, toxic for all crop species, are present in many soils, representing 6 % to 10 % of the earth's land area. Three families of ion channels (Shaker, TPK/KCO, and TPC) and 3 families of transporters (HAK, HKT, and CPA) have been identified so far as contributing to K(+) and Na(+) transport across the plasmalemma and internal membranes, with high or low ionic selectivity. In the model plant Arabidopsis thaliana, these families gather at least 70 members. Coordination of the activities of these systems, at the cell and whole plant levels, ensures plant K(+) nutrition, use of Na(+) as a beneficial element, and adaptation to saline conditions.
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Affiliation(s)
- Manuel Nieves-Cordones
- Laboratory of Plant Biochemistry and Molecular Physiology, UMR BPMP CNRS/INRA/MontpellierSupAgro, University of Montpellier, INRA, Place Viala, F-34060, Montpellier cedex 1, France
| | - Fouad Razzaq Al Shiblawi
- Laboratory of Plant Biochemistry and Molecular Physiology, UMR BPMP CNRS/INRA/MontpellierSupAgro, University of Montpellier, INRA, Place Viala, F-34060, Montpellier cedex 1, France
| | - Hervé Sentenac
- Laboratory of Plant Biochemistry and Molecular Physiology, UMR BPMP CNRS/INRA/MontpellierSupAgro, University of Montpellier, INRA, Place Viala, F-34060, Montpellier cedex 1, France.
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Chao Q, Gao ZF, Wang YF, Li Z, Huang XH, Wang YC, Mei YC, Zhao BG, Li L, Jiang YB, Wang BC. The proteome and phosphoproteome of maize pollen uncovers fertility candidate proteins. PLANT MOLECULAR BIOLOGY 2016; 91:287-304. [PMID: 26969016 DOI: 10.1007/s11103-016-0466-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 03/03/2016] [Indexed: 06/05/2023]
Abstract
Maize is unique since it is both monoecious and diclinous (separate male and female flowers on the same plant). We investigated the proteome and phosphoproteome of maize pollen containing modified proteins and here we provide a comprehensive pollen proteome and phosphoproteome which contain 100,990 peptides from 6750 proteins and 5292 phosphorylated sites corresponding to 2257 maize phosphoproteins, respectively. Interestingly, among the total 27 overrepresented phosphosite motifs we identified here, 11 were novel motifs, which suggested different modification mechanisms in plants compared to those of animals. Enrichment analysis of pollen phosphoproteins showed that pathways including DNA synthesis/chromatin structure, regulation of RNA transcription, protein modification, cell organization, signal transduction, cell cycle, vesicle transport, transport of ions and metabolisms, which were involved in pollen development, the following germination and pollen tube growth, were regulated by phosphorylation. In this study, we also found 430 kinases and 105 phosphatases in the maize pollen phosphoproteome, among which calcium dependent protein kinases (CDPKs), leucine rich repeat kinase, SNF1 related protein kinases and MAPK family proteins were heavily enriched and further analyzed. From our research, we also uncovered hundreds of male sterility-associated proteins and phosphoproteins that might influence maize productivity and serve as targets for hybrid maize seed production. At last, a putative complex signaling pathway involving CDPKs, MAPKs, ubiquitin ligases and multiple fertility proteins was constructed. Overall, our data provides new insight for further investigation of protein phosphorylation status in mature maize pollen and construction of maize male sterile mutants in the future.
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Affiliation(s)
- Qing Chao
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, No. 20 Nanxincun, Xiangshan, Beijing, 100093, China
| | - Zhi-Fang Gao
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, No. 20 Nanxincun, Xiangshan, Beijing, 100093, China
| | - Yue-Feng Wang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, No. 20 Nanxincun, Xiangshan, Beijing, 100093, China
| | - Zhe Li
- The State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Xia-He Huang
- Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Ying-Chun Wang
- Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Ying-Chang Mei
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, No. 20 Nanxincun, Xiangshan, Beijing, 100093, China
| | - Biligen-Gaowa Zhao
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, No. 20 Nanxincun, Xiangshan, Beijing, 100093, China
| | - Liang Li
- Institute of Crop Cultivation and Farming, Heilongjiang Academy of Agricultural Sciences, Harbin, 150086, China
| | - Yu-Bo Jiang
- Institute of Crop Cultivation and Farming, Heilongjiang Academy of Agricultural Sciences, Harbin, 150086, China
| | - Bai-Chen Wang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, No. 20 Nanxincun, Xiangshan, Beijing, 100093, China.
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80
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Hafidh S, Fíla J, Honys D. Male gametophyte development and function in angiosperms: a general concept. PLANT REPRODUCTION 2016; 29:31-51. [PMID: 26728623 DOI: 10.1007/s00497-015-0272-4] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2015] [Accepted: 12/19/2015] [Indexed: 05/23/2023]
Abstract
Overview of pollen development. Male gametophyte development of angiosperms is a complex process that requires coordinated activity of different cell types and tissues of both gametophytic and sporophytic origin and the appropriate specific gene expression. Pollen ontogeny is also an excellent model for the dissection of cellular networks that control cell growth, polarity, cellular differentiation and cell signaling. This article describes two sequential phases of angiosperm pollen ontogenesis-developmental phase leading to the formation of mature pollen grains, and a functional or progamic phase, beginning with the impact of the grains on the stigma surface and ending at double fertilization. Here we present an overview of important cellular processes in pollen development and explosive pollen tube growth stressing the importance of reserves accumulation and mobilization and also the mutual activation of pollen tube and pistil tissues, pollen tube guidance and the communication between male and female gametophytes. We further describe the recent advances in regulatory mechanisms involved such as posttranscriptional regulation (including mass transcript storage) and posttranslational modifications to modulate protein function, intracellular metabolic signaling, ionic gradients such as Ca(2+) and H(+) ions, cell wall synthesis, protein secretion and intercellular signaling within the reproductive tissues.
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Affiliation(s)
- Said Hafidh
- Institute of Experimental Botany ASCR, v.v.i., Rozvojová 263, 165 00, Prague 6, Czech Republic
| | - Jan Fíla
- Institute of Experimental Botany ASCR, v.v.i., Rozvojová 263, 165 00, Prague 6, Czech Republic
| | - David Honys
- Institute of Experimental Botany ASCR, v.v.i., Rozvojová 263, 165 00, Prague 6, Czech Republic.
- Department of Experimental Plant Biology, Faculty of Science, Charles University in Prague, Viničná 5, 128 44, Prague 2, Czech Republic.
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81
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Zhang M, Zhang R, Qu X, Huang S. Arabidopsis FIM5 decorates apical actin filaments and regulates their organization in the pollen tube. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:3407-17. [PMID: 27117336 PMCID: PMC4892729 DOI: 10.1093/jxb/erw160] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The actin cytoskeleton is increasingly recognized as a major regulator of pollen tube growth. Actin filaments have distinct distribution patterns and dynamic properties within different regions of the pollen tube. Apical actin filaments are highly dynamic and crucial for pollen tube growth. However, how apical actin filaments are generated and properly constructed remains an open question. Here we showed that Arabidopsis fimbrin5 (FIM5) decorates filamentous structures throughout the entire tube but is apically concentrated. Apical actin structures are disorganized to different degrees in the pollen tubes of fim5 loss-of-function mutants. Further observations suggest that apical actin structures are not constructed properly because apical actin filaments cannot be maintained at the cortex of fim5 pollen tubes. Actin filaments appeared to be more curved in fim5 pollen tubes and this was confirmed by measurements showing that the convolutedness and the rate of change of convolutedness of actin filaments was significantly increased in fim5 pollen tubes. This suggests that the rigidity of the actin filaments may be compromised in fim5 pollen tubes. Further, the apical cell wall composition is altered, implying that tip-directed vesicle trafficking events are impaired in fim5 pollen tubes. Thus, we found that FIM5 decorates apical actin filaments and regulates their organization in order to drive polarized pollen tube growth.
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Affiliation(s)
- Meng Zhang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany Chinese Academy of Sciences, Beijing 100093 China University of Chinese Academy of Sciences, Beijing 100049 China
| | - Ruihui Zhang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany Chinese Academy of Sciences, Beijing 100093 China University of Chinese Academy of Sciences, Beijing 100049 China
| | - Xiaolu Qu
- Center for Plant Biology, School of Life Sciences, Tsinghua University Beijing 100084, China Tsinghua-Peking Joint Center for Life Sciences, Beijing 100084 China
| | - Shanjin Huang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany Chinese Academy of Sciences, Beijing 100093 China Center for Plant Biology, School of Life Sciences, Tsinghua University Beijing 100084, China National Center for Plant Gene Research, Beijing 100101 China
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82
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Cyclic nucleotide-gated channel 18 is an essential Ca2+ channel in pollen tube tips for pollen tube guidance to ovules in Arabidopsis. Proc Natl Acad Sci U S A 2016; 113:3096-101. [PMID: 26929345 DOI: 10.1073/pnas.1524629113] [Citation(s) in RCA: 116] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
In flowering plants, pollen tubes are guided into ovules by multiple attractants from female gametophytes to release paired sperm cells for double fertilization. It has been well-established that Ca(2+) gradients in the pollen tube tips are essential for pollen tube guidance and that plasma membrane Ca(2+) channels in pollen tube tips are core components that regulate Ca(2+) gradients by mediating and regulating external Ca(2+) influx. Therefore, Ca(2+) channels are the core components for pollen tube guidance. However, there is still no genetic evidence for the identification of the putative Ca(2+) channels essential for pollen tube guidance. Here, we report that the point mutations R491Q or R578K in cyclic nucleotide-gated channel 18 (CNGC18) resulted in abnormal Ca(2+) gradients and strong pollen tube guidance defects by impairing the activation of CNGC18 in Arabidopsis. The pollen tube guidance defects of cngc18-17 (R491Q) and of the transfer DNA (T-DNA) insertion mutant cngc18-1 (+/-) were completely rescued by CNGC18. Furthermore, domain-swapping experiments showed that CNGC18's transmembrane domains are indispensable for pollen tube guidance. Additionally, we found that, among eight Ca(2+) channels (including six CNGCs and two glutamate receptor-like channels), CNGC18 was the only one essential for pollen tube guidance. Thus, CNGC18 is the long-sought essential Ca(2+) channel for pollen tube guidance in Arabidopsis.
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83
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An Y, Li J, Duan C, Liu L, Sun Y, Cao R, Wang L. 5-Aminolevulinic Acid Thins Pear Fruits by Inhibiting Pollen Tube Growth via Ca(2+)-ATPase-Mediated Ca(2+) Efflux. FRONTIERS IN PLANT SCIENCE 2016; 7:121. [PMID: 26904082 PMCID: PMC4746310 DOI: 10.3389/fpls.2016.00121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 01/22/2016] [Indexed: 05/08/2023]
Abstract
Chemical fruit thinning has become a popular practice in modern fruit orchards for achieving high quality fruits, reducing costs of hand thinning and promoting return bloom. However, most of the suggested chemical thinners are often concerned for their detrimental effects and environmental problems. 5-Aminolevulic acid (ALA) is a natural, nontoxic, biodegradable, and environment-friendly plant growth regulator. One of its outstanding roles is improving plant photosynthesis and fruit quality. Here, results showed that applying 100-200 mg/L ALA at full bloom stage significantly reduced pear fruit set. Both in vivo and in vitro studies showed that ALA significantly inhibited pollen germination and tube growth. ALA decreased not only cytosolic Ca(2+) concentration ([Ca(2+)]cyt) but also "tip-focused" [Ca(2+)]cyt gradient, indicating that ALA inhibited pollen tube growth by down-regulating calcium signaling. ALA drastically enhanced pollen Ca(2+)-ATPase activity, suggesting that ALA-induced decrease of calcium signaling probably resulted from activating calcium pump. The significant negative correlations between Ca(2+)-ATPase activity and pollen germination or pollen tube length further demonstrated the critical role of calcium pump in ALA's negative effect on pollen germination. Taken together, our results suggest that ALA at low concentrations is a potential biochemical thinner, and it inhibits pollen germination and tube growth via Ca(2+) efflux by activating Ca(2+)-ATPase, thereby thinning fruits by preventing fertilization.
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Affiliation(s)
- Yuyan An
- College of Horticulture, Nanjing Agricultural UniversityNanjing, China
| | - Jie Li
- College of Horticulture, Nanjing Agricultural UniversityNanjing, China
| | - Chunhui Duan
- College of Horticulture, Nanjing Agricultural UniversityNanjing, China
| | - Longbo Liu
- College of Horticulture, Nanjing Agricultural UniversityNanjing, China
| | - Yongping Sun
- Nanjing Institute of Agricultural SciencesNanjing, China
| | - Rongxiang Cao
- Nanjing Institute of Agricultural SciencesNanjing, China
| | - Liangju Wang
- College of Horticulture, Nanjing Agricultural UniversityNanjing, China
- *Correspondence: Liangju Wang
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84
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Liu X, Qu X, Jiang Y, Chang M, Zhang R, Wu Y, Fu Y, Huang S. Profilin Regulates Apical Actin Polymerization to Control Polarized Pollen Tube Growth. MOLECULAR PLANT 2015; 8:1694-709. [PMID: 26433093 DOI: 10.1016/j.molp.2015.09.013] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2015] [Revised: 09/14/2015] [Accepted: 09/25/2015] [Indexed: 05/23/2023]
Abstract
Pollen tube growth is an essential step during flowering plant reproduction, whose growth depends on a population of dynamic apical actin filaments. Apical actin filaments were thought to be involved in the regulation of vesicle fusion and targeting in the pollen tube. However, the molecular mechanisms that regulate the construction of apical actin structures in the pollen tube remain largely unclear. Here, we identify profilin as an important player in the regulation of actin polymerization at the apical membrane in the pollen tube. Downregulation of profilin decreased the amount of filamentous actin and induced disorganization of apical actin filaments, and reduced tip-directed vesicle transport and accumulation in the pollen tube. Direct visualization of actin dynamics revealed that the elongation of actin filaments originating at the apical membrane decreased in profilin mutant pollen tubes. Mutant profilin that is defective in binding poly-L-proline only partially rescues the actin polymerization defect in profilin mutant pollen tubes, although it fully rescues the actin turnover phenotype. We propose that profilin controls the construction of actin structures at the pollen tube tip, presumably by favoring formin-mediated actin polymerization at the apical membrane.
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Affiliation(s)
- Xiaonan Liu
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China; Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Xiaolu Qu
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China; Tsinghua-Peking Joint Center for Life Sciences, Beijing 100084, China
| | - Yuxiang Jiang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Ming Chang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Ruihui Zhang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Youjun Wu
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Ying Fu
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Shanjin Huang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China; National Center for Plant Gene Research, Beijing 100101, China.
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85
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Fu Y. The cytoskeleton in the pollen tube. CURRENT OPINION IN PLANT BIOLOGY 2015; 28:111-9. [PMID: 26550939 DOI: 10.1016/j.pbi.2015.10.004] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Revised: 10/07/2015] [Accepted: 10/12/2015] [Indexed: 05/10/2023]
Abstract
The cytoskeleton in pollen tubes has been intensively studied, because of its abundance and prominent roles and because the pollen tube is an excellent experimental system for cell biological studies. Pollen actin microfilaments (MFs) exist as multiple distinct populations, each participating in a specific cellular trafficking or organization process. Consequently, MFs are essential for pollen tube growth and are tightly regulated in response to various signals. Pollen microtubules (MTs) are non-essential and less characterized, but recent studies have implicated MTs in vesicle trafficking and cell wall construction in pollen tubes. This review summarizes recent advances in understanding the organization and regulation of both MFs and MTs and discusses their roles in cellular trafficking and the modulation of pollen-tube tip growth.
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Affiliation(s)
- Ying Fu
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China.
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86
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Gene-expression profile of developing pollen tube of Pyrus bretschneideri. Gene Expr Patterns 2015; 20:11-21. [PMID: 26547040 DOI: 10.1016/j.gep.2015.10.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Revised: 10/28/2015] [Accepted: 10/30/2015] [Indexed: 11/23/2022]
Abstract
Pollen is an ideal model system for investigation of cell growth. In order to better understand the molecular biology mechanisms of the process of pear pollen tube development, RNA sequencing (RNA-Seq) technology was used to characterize the expression of genes during four development stages of pear pollen, including mature pollen grains (MP), hydrated pollen grains (HP), growing pollen tubes (PT) and stopped-growth pollen tubes (SPT). The four libraries generated a total of 47,072,151 clean reads that were mapped and assembled into 21,394 genes. Transcripts from the four stages were classified into 38 functional subcategories. Between MP and HP, 305 genes were differentially expressed, and 502 genes were differentially expressed between HP and PT. More importantly, we have observed that 2208 genes were differentially expressed between PT and SPT, and this is the first report of the gene expression comparison between the two development stages. Eight of the differentially expressed genes were randomly selected to confirm the RNA-Seq results by quantitative real-time PCR (qRT-PCR). Taken together, this research provides a platform for future research on pear pollen tube growth and growth cessation.
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87
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Wang SS, Diao WZ, Yang X, Qiao Z, Wang M, Acharya BR, Zhang W. Arabidopsis thaliana CML25 mediates the Ca(2+) regulation of K(+) transmembrane trafficking during pollen germination and tube elongation. PLANT, CELL & ENVIRONMENT 2015; 38:2372-86. [PMID: 25923414 DOI: 10.1111/pce.12559] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 04/09/2015] [Indexed: 05/10/2023]
Abstract
The concentration alteration of cytosolic-free calcium ([Ca(2+) ]cyt ) is a well-known secondary messenger in plants and plays important roles during pollen grain germination and tube elongation. Here we demonstrate that CML25, a member of calmodulin-like proteins, has Ca(2+) -binding activity and plays a role in pollen grain germination, tube elongation and seed setting. CML25 transcript was abundant in mature pollen grains and pollen tubes, and its product CML25 protein was primarily directed to the cytoplasm. Two independent CML25 loss-of-function T-DNA insertion mutants suffered a major reduction in both the rate of pollen germination and the elongation of the pollen tube. Also, pollen grains of cml25 mutants were less sensitive to the external K(+) and Ca(2+) concentration than wild-type pollen. The disruption of CML25 increased the [Ca(2+) ]cyt in both the pollen grain and the pollen tube, which in turn impaired the Ca(2+) -dependent inhibition of whole-cell inward K(+) currents in protoplasts prepared from these materials (pollen grain and pollen tube). Complementation of cml25-1 mutant resulted in the recovery of wild-type phenotype. Our findings indicate that CML25 is an important transducer in the Ca(2+) -mediated regulation of K(+) influx during pollen germination and tube elongation.
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Affiliation(s)
- Shuang-Shuang Wang
- Key Laboratory of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, School of Life Science, Shandong University, Jinan, 250100, China
| | - Wen-Zhu Diao
- Key Laboratory of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, School of Life Science, Shandong University, Jinan, 250100, China
| | - Xue Yang
- Key Laboratory of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, School of Life Science, Shandong University, Jinan, 250100, China
- College of Technological Gardening, Shandong Yingcai University, Jinan, 250104, China
| | - Zhu Qiao
- Key Laboratory of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, School of Life Science, Shandong University, Jinan, 250100, China
| | - Mei Wang
- Key Laboratory of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, School of Life Science, Shandong University, Jinan, 250100, China
| | - Biswa R Acharya
- Department of Biology, Pennsylvania State University University Park, State College, PA, 16802, USA
| | - Wei Zhang
- Key Laboratory of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, School of Life Science, Shandong University, Jinan, 250100, China
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88
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Muiño JM, de Bruijn S, Pajoro A, Geuten K, Vingron M, Angenent GC, Kaufmann K. Evolution of DNA-Binding Sites of a Floral Master Regulatory Transcription Factor. Mol Biol Evol 2015; 33:185-200. [PMID: 26429922 PMCID: PMC4693976 DOI: 10.1093/molbev/msv210] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Flower development is controlled by the action of key regulatory transcription factors of the MADS-domain family. The function of these factors appears to be highly conserved among species based on mutant phenotypes. However, the conservation of their downstream processes is much less well understood, mostly because the evolutionary turnover and variation of their DNA-binding sites (BSs) among plant species have not yet been experimentally determined. Here, we performed comparative ChIP (chromatin immunoprecipitation)-seq experiments of the MADS-domain transcription factor SEPALLATA3 (SEP3) in two closely related Arabidopsis species: Arabidopsis thaliana and A. lyrata which have very similar floral organ morphology. We found that BS conservation is associated with DNA sequence conservation, the presence of the CArG-box BS motif and on the relative position of the BS to its potential target gene. Differences in genome size and structure can explain that SEP3 BSs in A. lyrata can be located more distantly to their potential target genes than their counterparts in A. thaliana. In A. lyrata, we identified transposition as a mechanism to generate novel SEP3 binding locations in the genome. Comparative gene expression analysis shows that the loss/gain of BSs is associated with a change in gene expression. In summary, this study investigates the evolutionary dynamics of DNA BSs of a floral key-regulatory transcription factor and explores factors affecting this phenomenon.
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Affiliation(s)
- Jose M Muiño
- Computational Molecular Biology, Max Planck Institute for Molecular Genetics, Berlin, Germany Laboratory of Bioinformatics, Wageningen University, Wageningen, The Netherlands
| | - Suzanne de Bruijn
- Institute for Biochemistry and Biology, Potsdam University, Potsdam, Germany Laboratory of Molecular Biology, Wageningen University, Wageningen, The Netherlands
| | - Alice Pajoro
- Laboratory of Molecular Biology, Wageningen University, Wageningen, The Netherlands
| | - Koen Geuten
- Laboratory of Molecular Plant Biology, Department of Biology, University of Leuven (KU Leuven), Leuven, Belgium
| | - Martin Vingron
- Computational Molecular Biology, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Gerco C Angenent
- Laboratory of Molecular Biology, Wageningen University, Wageningen, The Netherlands Bioscience, Plant Research International, Wageningen, The Netherlands
| | - Kerstin Kaufmann
- Institute for Biochemistry and Biology, Potsdam University, Potsdam, Germany
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89
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Fehér A, Lajkó DB. Signals fly when kinases meet Rho-of-plants (ROP) small G-proteins. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2015; 237:93-107. [PMID: 26089155 DOI: 10.1016/j.plantsci.2015.05.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2015] [Revised: 05/11/2015] [Accepted: 05/12/2015] [Indexed: 05/11/2023]
Abstract
Rho-type small GTP-binding plant proteins function as two-state molecular switches in cellular signalling. There is accumulating evidence that Rho-of-plants (ROP) signalling is positively controlled by plant receptor kinases, through the ROP guanine nucleotide exchange factor proteins. These signalling modules regulate cell polarity, cell shape, hormone responses, and pathogen defence, among other things. Other ROP-regulatory proteins might also be subjected to protein phosphorylation by cellular kinases (e.g., mitogen-activated protein kinases or calcium-dependent protein kinases), in order to integrate various cellular signalling pathways with ROP GTPase-dependent processes. In contrast to the role of kinases in upstream ROP regulation, much less is known about the potential link between ROP GTPases and downstream kinase signalling. In other eukaryotes, Rho-type G-protein-activated kinases are widespread and have a key role in many cellular processes. Recent data indicate the existence of structurally different ROP-activated kinases in plants, but their ROP-dependent biological functions still need to be validated. In addition to these direct interactions, ROPs may also indirectly control the activity of mitogen-activated protein kinases or calcium-dependent protein kinases. These kinases may therefore function as upstream as well as downstream kinases in ROP-mediated signalling pathways, such as the phosphatidylinositol monophosphate kinases involved in cell polarity establishment.
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Affiliation(s)
- Attila Fehér
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Temesvári krt. 62, H-6726 Szeged, Hungary.
| | - Dézi Bianka Lajkó
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Temesvári krt. 62, H-6726 Szeged, Hungary
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90
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Qu LJ, Li L, Lan Z, Dresselhaus T. Peptide signalling during the pollen tube journey and double fertilization. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:5139-50. [PMID: 26068467 DOI: 10.1093/jxb/erv275] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Flowering seed plants (angiosperms) have evolved unique ways to protect their gametes from pathogen attack and from drying out. The female gametes (egg and central cell) are deeply embedded in the maternal tissues of the ovule inside the ovary, while the male gametes (sperm cells) are enclosed in the vegetative pollen tube cell. After germination of the pollen tube at the surface of papilla cells of the stigma the two immobile sperm cells are transported deep inside the sporophytic maternal tissues to be released inside the ovule for double fertilization. Angiosperms have evolved a number of hurdles along the pollen tube journey to prevent inbreeding and fertilization by alien sperm cells, and to maximize reproductive success. These pre-zygotic hybridization barriers require intensive communication between the male and female reproductive cells and the necessity to distinguish self from non-self interaction partners. General molecules such as nitric oxide (NO) or gamma-aminobutyric acid (GABA) therefore appear to play only a minor role in these species-specific communication events. The past 20 years have shown that highly polymorphic peptides play a leading role in all communication steps along the pollen tube pathway and fertilization. Here we review our current understanding of the role of peptides during reproduction with a focus on peptide signalling during self-incompatibility, pollen tube growth and guidance as well as sperm reception and gamete activation.
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Affiliation(s)
- Li-Jia Qu
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing 100871, China
| | - Ling Li
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing 100871, China
| | - Zijun Lan
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing 100871, China
| | - Thomas Dresselhaus
- Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of Regensburg, 93053 Regensburg, Germany
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91
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Suwińska A, Lenartowski R, Smoliński DJ, Lenartowska M. Molecular evidence that rough endoplasmic reticulum is the site of calreticulin translation in Petunia pollen tubes growing in vitro. PLANT CELL REPORTS 2015; 34:1189-99. [PMID: 25732863 PMCID: PMC4464644 DOI: 10.1007/s00299-015-1777-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 01/23/2015] [Accepted: 02/17/2015] [Indexed: 05/20/2023]
Abstract
KEY MESSAGE In germinating pollen grains and growing pollen tubes, CRT is translated on ER membrane-bound ribosomes in the regions where its activity is required for stabilization of tip-focused Ca (2+) gradient. Pollen tube growth requires coordination of signaling, exocytosis, and actin cytoskeletal organization. Many of these processes are thought to be controlled by finely tuned regulation of cytoplasmic Ca(2+) in discrete regions of the tube cytoplasm. Most notably, a mechanism must function to maintain a steep gradient of Ca(2+) that exists at the tip of growing pollen tube. Several pieces of evidence point to calreticulin (CRT) as a key Ca(2+)-binding/-buffering protein involved in pollen germination and pollen tube growth. We previously hypothesized that in germinating pollen and growing tubes, CRT is translated on the ribosomes associated with endoplasmic reticulum (ER) in the regions where its activity might be required. In this report, we have addressed this idea by identifying the sites where CRT mRNA, CRT protein, 18S rRNA, and rough ER are localized in Petunia pollen tubes. We observed all four components in the germinal aperture of pollen grains and in subapical regions of elongating tubes. These results seem to support our idea that CRT is translated on ER membrane-bound ribosomes during pollen germination and pollen tube growth. In elongated pollen tubes, we found CRT mainly localized in the subapical zone, where ER and Golgi stacks are abundant. In eukaryotic cells, these organelles serve as mobile intracellular stores of easily releasable Ca(2+), which can be buffered by proteins such as CRT. Therefore, we postulate that subapical-localized CRT is involved in pollen tube growth by maintaining the stable tip-focused Ca(2+) gradient and thus modulating local Ca(2+) concentration within the tube cytoplasm.
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Affiliation(s)
- Anna Suwińska
- Laboratory of Developmental Biology, Faculty of Biology and Environment Protection, Nicolaus Copernicus University, Toruń, Poland
| | - Robert Lenartowski
- Laboratory of Isotope and Instrumental Analysis, Faculty of Biology and Environment Protection, Nicolaus Copernicus University, Toruń, Poland
| | - Dariusz Jan Smoliński
- Department of Cell Biology, Faculty of Biology and Environment Protection, Nicolaus Copernicus University, Toruń, Poland
| | - Marta Lenartowska
- Laboratory of Developmental Biology, Faculty of Biology and Environment Protection, Nicolaus Copernicus University, Toruń, Poland
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Suo J, Zhao Q, Zhang Z, Chen S, Cao J, Liu G, Wei X, Wang T, Yang C, Dai S. Cytological and Proteomic Analyses of Osmunda cinnamomea Germinating Spores Reveal Characteristics of Fern Spore Germination and Rhizoid Tip Growth. Mol Cell Proteomics 2015; 14:2510-34. [PMID: 26091698 DOI: 10.1074/mcp.m114.047225] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Indexed: 12/29/2022] Open
Abstract
Fern spore is a good single-cell model for studying the sophisticated molecular networks in asymmetric cell division, differentiation, and polar growth. Osmunda cinnamomea L. var. asiatica is one of the oldest fern species with typical separate-growing trophophyll and sporophyll. The chlorophyllous spores generated from sporophyll can germinate without dormancy. In this study, the spore ultrastructure, antioxidant enzyme activities, as well as protein and gene expression patterns were analyzed in the course of spore germination at five typical stages (i.e. mature spores, rehydrated spores, double-celled spores, germinated spores, and spores with protonemal cells). Proteomic analysis revealed 113 differentially expressed proteins, which were mainly involved in photosynthesis, reserve mobilization, energy supplying, protein synthesis and turnover, reactive oxygen species scavenging, signaling, and cell structure modulation. The presence of multiple proteoforms of 25 differentially expressed proteins implies that post-translational modification may play important roles in spore germination. The dynamic patterns of proteins and their encoding genes exhibited specific characteristics in the processes of cell division and rhizoid tip growth, which include heterotrophic and autotrophic metabolisms, de novo protein synthesis and active protein turnover, reactive oxygen species and hormone (brassinosteroid and ethylene) signaling, and vesicle trafficking and cytoskeleton dynamic. In addition, the function skew of proteins in fern spores highlights the unique and common mechanisms when compared with evolutionarily divergent spermatophyte pollen. These findings provide an improved understanding of the typical single-celled asymmetric division and polar growth during fern spore germination.
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Affiliation(s)
- Jinwei Suo
- From the ‡Alkali Soil Natural Environmental Science Center, Northeast Forestry University, Key Laboratory of Saline-alkali Vegetation Ecology Restoration in Oil Field, Ministry of Education, Harbin 150040, China
| | - Qi Zhao
- From the ‡Alkali Soil Natural Environmental Science Center, Northeast Forestry University, Key Laboratory of Saline-alkali Vegetation Ecology Restoration in Oil Field, Ministry of Education, Harbin 150040, China
| | - Zhengxiu Zhang
- From the ‡Alkali Soil Natural Environmental Science Center, Northeast Forestry University, Key Laboratory of Saline-alkali Vegetation Ecology Restoration in Oil Field, Ministry of Education, Harbin 150040, China
| | - Sixue Chen
- ‖Department of Biology, Genetics Institute, Plant Molecular and Cellular Biology Program, Interdisciplinary Center for Biotechnology Research, University of Florida, Gainesville, Florida 32610
| | - Jian'guo Cao
- ¶College of Life and Environmental Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Guanjun Liu
- §State Key Laboratory of Tree Genetics and Breeding (Northeast Forestry University), School of Forestry, Northeast Forestry University, Harbin 150040, China
| | - Xing Wei
- §State Key Laboratory of Tree Genetics and Breeding (Northeast Forestry University), School of Forestry, Northeast Forestry University, Harbin 150040, China
| | - Tai Wang
- **Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Chuanping Yang
- §State Key Laboratory of Tree Genetics and Breeding (Northeast Forestry University), School of Forestry, Northeast Forestry University, Harbin 150040, China
| | - Shaojun Dai
- From the ‡Alkali Soil Natural Environmental Science Center, Northeast Forestry University, Key Laboratory of Saline-alkali Vegetation Ecology Restoration in Oil Field, Ministry of Education, Harbin 150040, China; §State Key Laboratory of Tree Genetics and Breeding (Northeast Forestry University), School of Forestry, Northeast Forestry University, Harbin 150040, China;
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93
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Zhou L, Lan W, Chen B, Fang W, Luan S. A calcium sensor-regulated protein kinase, CALCINEURIN B-LIKE PROTEIN-INTERACTING PROTEIN KINASE19, is required for pollen tube growth and polarity. PLANT PHYSIOLOGY 2015; 167:1351-60. [PMID: 25713341 PMCID: PMC4378171 DOI: 10.1104/pp.114.256065] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 02/17/2015] [Indexed: 05/17/2023]
Abstract
Calcium plays an essential role in pollen tube tip growth. However, little is known concerning the molecular basis of the signaling pathways involved. Here, we identified Arabidopsis (Arabidopsis thaliana) CALCINEURIN B-LIKE PROTEIN-INTERACTING PROTEIN KINASE19 (CIPK19) as an important element to pollen tube growth through a functional survey for CIPK family members. The CIPK19 gene was specifically expressed in pollen grains and pollen tubes, and its overexpression induced severe loss of polarity in pollen tube growth. In the CIPK19 loss-of-function mutant, tube growth and polarity were significantly impaired, as demonstrated by both in vitro and in vivo pollen tube growth assays. Genetic analysis indicated that disruption of CIPK19 resulted in a male-specific transmission defect. Furthermore, loss of polarity induced by CIPK19 overexpression was associated with elevated cytosolic Ca2+ throughout the bulging tip, whereas LaCl3, a Ca2+ influx blocker, rescued CIPK19 overexpression-induced growth inhibition. Our results suggest that CIPK19 may be involved in maintaining Ca2+ homeostasis through its potential function in the modulation of Ca2+ influx.
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Affiliation(s)
- Liming Zhou
- College of Life Sciences, Fujian Agriculture and Forestry University, Fujian, Fuzhou 350002, China (L.Z., W.F.);Nanjing University-Nanjing Forestry University Joint Institute for Plant Molecular Biology, School of Life Sciences, Nanjing University, Nanjing 210093, China (W.L., S.L.);College of Biological Sciences, China Agricultural University, Beijing 100193, China (B.C.); andDepartment of Plant and Microbial Biology, University of California, Berkeley, California 94720 (S.L.)
| | - Wenzhi Lan
- College of Life Sciences, Fujian Agriculture and Forestry University, Fujian, Fuzhou 350002, China (L.Z., W.F.);Nanjing University-Nanjing Forestry University Joint Institute for Plant Molecular Biology, School of Life Sciences, Nanjing University, Nanjing 210093, China (W.L., S.L.);College of Biological Sciences, China Agricultural University, Beijing 100193, China (B.C.); andDepartment of Plant and Microbial Biology, University of California, Berkeley, California 94720 (S.L.)
| | - Binqing Chen
- College of Life Sciences, Fujian Agriculture and Forestry University, Fujian, Fuzhou 350002, China (L.Z., W.F.);Nanjing University-Nanjing Forestry University Joint Institute for Plant Molecular Biology, School of Life Sciences, Nanjing University, Nanjing 210093, China (W.L., S.L.);College of Biological Sciences, China Agricultural University, Beijing 100193, China (B.C.); andDepartment of Plant and Microbial Biology, University of California, Berkeley, California 94720 (S.L.)
| | - Wei Fang
- College of Life Sciences, Fujian Agriculture and Forestry University, Fujian, Fuzhou 350002, China (L.Z., W.F.);Nanjing University-Nanjing Forestry University Joint Institute for Plant Molecular Biology, School of Life Sciences, Nanjing University, Nanjing 210093, China (W.L., S.L.);College of Biological Sciences, China Agricultural University, Beijing 100193, China (B.C.); andDepartment of Plant and Microbial Biology, University of California, Berkeley, California 94720 (S.L.)
| | - Sheng Luan
- College of Life Sciences, Fujian Agriculture and Forestry University, Fujian, Fuzhou 350002, China (L.Z., W.F.);Nanjing University-Nanjing Forestry University Joint Institute for Plant Molecular Biology, School of Life Sciences, Nanjing University, Nanjing 210093, China (W.L., S.L.);College of Biological Sciences, China Agricultural University, Beijing 100193, China (B.C.); andDepartment of Plant and Microbial Biology, University of California, Berkeley, California 94720 (S.L.)
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94
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Qin Y, Dong J. Focusing on the focus: what else beyond the master switches for polar cell growth? MOLECULAR PLANT 2015; 8:582-94. [PMID: 25744359 PMCID: PMC5124495 DOI: 10.1016/j.molp.2014.12.023] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2014] [Revised: 12/24/2014] [Accepted: 12/29/2014] [Indexed: 05/21/2023]
Abstract
Cell polarity, often associated with polarized cell expansion/growth in plants, describes the uneven distribution of cellular components, such as proteins, nucleic acids, signaling molecules, vesicles, cytoskeletal elements, and organelles, which may ultimately modulate cell shape, structure, and function. Pollen tubes and root hairs are model cell systems for studying the molecular mechanisms underlying sustained tip growth. The formation of intercalated epidermal pavement cells requires excitatory and inhibitory pathways to coordinate cell expansion within single cells and between cells in contact. Strictly controlled cell expansion is linked to asymmetric cell division in zygotes and stomatal lineages, which require integrated processes of pre-mitotic cellular polarization and division asymmetry. While small GTPase ROPs are recognized as fundamental signaling switches for cell polarity in various cellular and developmental processes in plants, the broader molecular machinery underpinning polarity establishment required for asymmetric division remains largely unknown. Here, we review the widely used ROP signaling pathways in cell polar growth and the recently discovered feedback loops with auxin signaling and PIN effluxers. We discuss the conserved phosphorylation and phospholipid signaling mechanisms for regulating uneven distribution of proteins, as well as the potential roles of novel proteins and MAPKs in the polarity establishment related to asymmetric cell division in plants.
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Affiliation(s)
- Yuan Qin
- Center for Genomics and Biotechnology, College of Crop Science, Fujian Agriculture and Forestry University, Fuzhou 350002, Fujian Province, China
| | - Juan Dong
- Waksman Institute of Microbiology, Rutgers the State University of New Jersey, Piscataway, NJ 08854, USA; The Department of Plant Biology and Pathology, Rutgers the State University of New Jersey, New Brunswick, NJ 08901, USA.
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95
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Calcium is an organizer of cell polarity in plants. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:2168-72. [PMID: 25725133 DOI: 10.1016/j.bbamcr.2015.02.017] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Revised: 02/05/2015] [Accepted: 02/17/2015] [Indexed: 01/07/2023]
Abstract
Cell polarity is a fundamental property of pro- and eukaryotic cells. It is necessary for coordination of cell division, cell morphogenesis and signaling processes. How polarity is generated and maintained is a complex issue governed by interconnected feed-back regulations between small GTPase signaling and membrane tension-based signaling that controls membrane trafficking, and cytoskeleton organization and dynamics. Here, we will review the potential role for calcium as a crucial signal that connects and coordinates the respective processes during polarization processes in plants. This article is part of a Special Issue entitled: 13th European Symposium on Calcium.
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96
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Leroux C, Bouton S, Kiefer-Meyer MC, Fabrice TN, Mareck A, Guénin S, Fournet F, Ringli C, Pelloux J, Driouich A, Lerouge P, Lehner A, Mollet JC. PECTIN METHYLESTERASE48 is involved in Arabidopsis pollen grain germination. PLANT PHYSIOLOGY 2015; 167:367-80. [PMID: 25524442 PMCID: PMC4326738 DOI: 10.1104/pp.114.250928] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 12/16/2014] [Indexed: 05/18/2023]
Abstract
Germination of pollen grains is a crucial step in plant reproduction. However, the molecular mechanisms involved remain unclear. We investigated the role of PECTIN METHYLESTERASE48 (PME48), an enzyme implicated in the remodeling of pectins in Arabidopsis (Arabidopsis thaliana) pollen. A combination of functional genomics, gene expression, in vivo and in vitro pollen germination, immunolabeling, and biochemical analyses was used on wild-type and Atpme48 mutant plants. We showed that AtPME48 is specifically expressed in the male gametophyte and is the second most expressed PME in dry and imbibed pollen grains. Pollen grains from homozygous mutant lines displayed a significant delay in imbibition and germination in vitro and in vivo. Moreover, numerous pollen grains showed two tips emerging instead of one in the wild type. Immunolabeling and Fourier transform infrared analyses showed that the degree of methylesterification of the homogalacturonan was higher in pme48-/- pollen grains. In contrast, the PME activity was lower in pme48-/-, partly due to a reduction of PME48 activity revealed by zymogram. Interestingly, the wild-type phenotype was restored in pme48-/- with the optimum germination medium supplemented with 2.5 mm calcium chloride, suggesting that in the wild-type pollen, the weakly methylesterified homogalacturonan is a source of Ca(2+) necessary for pollen germination. Although pollen-specific PMEs are traditionally associated with pollen tube elongation, this study provides strong evidence that PME48 impacts the mechanical properties of the intine wall during maturation of the pollen grain, which, in turn, influences pollen grain germination.
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Affiliation(s)
- Christelle Leroux
- Laboratoire Glycobiologie et Matrice Extracellulaire, Normandie Université, Institute for Research and Innovation in Biomedicine, Végétal, Agronomie, Sol, et Innovation, 76821 Mont-Saint-Aignan, France (C.L., M.-C.K.-M., A.M., A.D., P.L., A.L., J.-C.M.);Unité Biologie des Plantes et Innovation (S.B., S.G., F.F., J.P.) and Centre de Ressources Régionales en Biologie Moléculaire (S.G.), Université de Picardie Jules Verne, 80039 Amiens, France; andInstitute of Plant Biology, University of Zürich, 8008 Zurich, Switzerland (T.N.F., C.R.)
| | - Sophie Bouton
- Laboratoire Glycobiologie et Matrice Extracellulaire, Normandie Université, Institute for Research and Innovation in Biomedicine, Végétal, Agronomie, Sol, et Innovation, 76821 Mont-Saint-Aignan, France (C.L., M.-C.K.-M., A.M., A.D., P.L., A.L., J.-C.M.);Unité Biologie des Plantes et Innovation (S.B., S.G., F.F., J.P.) and Centre de Ressources Régionales en Biologie Moléculaire (S.G.), Université de Picardie Jules Verne, 80039 Amiens, France; andInstitute of Plant Biology, University of Zürich, 8008 Zurich, Switzerland (T.N.F., C.R.)
| | - Marie-Christine Kiefer-Meyer
- Laboratoire Glycobiologie et Matrice Extracellulaire, Normandie Université, Institute for Research and Innovation in Biomedicine, Végétal, Agronomie, Sol, et Innovation, 76821 Mont-Saint-Aignan, France (C.L., M.-C.K.-M., A.M., A.D., P.L., A.L., J.-C.M.);Unité Biologie des Plantes et Innovation (S.B., S.G., F.F., J.P.) and Centre de Ressources Régionales en Biologie Moléculaire (S.G.), Université de Picardie Jules Verne, 80039 Amiens, France; andInstitute of Plant Biology, University of Zürich, 8008 Zurich, Switzerland (T.N.F., C.R.)
| | - Tohnyui Ndinyanka Fabrice
- Laboratoire Glycobiologie et Matrice Extracellulaire, Normandie Université, Institute for Research and Innovation in Biomedicine, Végétal, Agronomie, Sol, et Innovation, 76821 Mont-Saint-Aignan, France (C.L., M.-C.K.-M., A.M., A.D., P.L., A.L., J.-C.M.);Unité Biologie des Plantes et Innovation (S.B., S.G., F.F., J.P.) and Centre de Ressources Régionales en Biologie Moléculaire (S.G.), Université de Picardie Jules Verne, 80039 Amiens, France; andInstitute of Plant Biology, University of Zürich, 8008 Zurich, Switzerland (T.N.F., C.R.)
| | - Alain Mareck
- Laboratoire Glycobiologie et Matrice Extracellulaire, Normandie Université, Institute for Research and Innovation in Biomedicine, Végétal, Agronomie, Sol, et Innovation, 76821 Mont-Saint-Aignan, France (C.L., M.-C.K.-M., A.M., A.D., P.L., A.L., J.-C.M.);Unité Biologie des Plantes et Innovation (S.B., S.G., F.F., J.P.) and Centre de Ressources Régionales en Biologie Moléculaire (S.G.), Université de Picardie Jules Verne, 80039 Amiens, France; andInstitute of Plant Biology, University of Zürich, 8008 Zurich, Switzerland (T.N.F., C.R.)
| | - Stéphanie Guénin
- Laboratoire Glycobiologie et Matrice Extracellulaire, Normandie Université, Institute for Research and Innovation in Biomedicine, Végétal, Agronomie, Sol, et Innovation, 76821 Mont-Saint-Aignan, France (C.L., M.-C.K.-M., A.M., A.D., P.L., A.L., J.-C.M.);Unité Biologie des Plantes et Innovation (S.B., S.G., F.F., J.P.) and Centre de Ressources Régionales en Biologie Moléculaire (S.G.), Université de Picardie Jules Verne, 80039 Amiens, France; andInstitute of Plant Biology, University of Zürich, 8008 Zurich, Switzerland (T.N.F., C.R.)
| | - Françoise Fournet
- Laboratoire Glycobiologie et Matrice Extracellulaire, Normandie Université, Institute for Research and Innovation in Biomedicine, Végétal, Agronomie, Sol, et Innovation, 76821 Mont-Saint-Aignan, France (C.L., M.-C.K.-M., A.M., A.D., P.L., A.L., J.-C.M.);Unité Biologie des Plantes et Innovation (S.B., S.G., F.F., J.P.) and Centre de Ressources Régionales en Biologie Moléculaire (S.G.), Université de Picardie Jules Verne, 80039 Amiens, France; andInstitute of Plant Biology, University of Zürich, 8008 Zurich, Switzerland (T.N.F., C.R.)
| | - Christoph Ringli
- Laboratoire Glycobiologie et Matrice Extracellulaire, Normandie Université, Institute for Research and Innovation in Biomedicine, Végétal, Agronomie, Sol, et Innovation, 76821 Mont-Saint-Aignan, France (C.L., M.-C.K.-M., A.M., A.D., P.L., A.L., J.-C.M.);Unité Biologie des Plantes et Innovation (S.B., S.G., F.F., J.P.) and Centre de Ressources Régionales en Biologie Moléculaire (S.G.), Université de Picardie Jules Verne, 80039 Amiens, France; andInstitute of Plant Biology, University of Zürich, 8008 Zurich, Switzerland (T.N.F., C.R.)
| | - Jérôme Pelloux
- Laboratoire Glycobiologie et Matrice Extracellulaire, Normandie Université, Institute for Research and Innovation in Biomedicine, Végétal, Agronomie, Sol, et Innovation, 76821 Mont-Saint-Aignan, France (C.L., M.-C.K.-M., A.M., A.D., P.L., A.L., J.-C.M.);Unité Biologie des Plantes et Innovation (S.B., S.G., F.F., J.P.) and Centre de Ressources Régionales en Biologie Moléculaire (S.G.), Université de Picardie Jules Verne, 80039 Amiens, France; andInstitute of Plant Biology, University of Zürich, 8008 Zurich, Switzerland (T.N.F., C.R.)
| | - Azeddine Driouich
- Laboratoire Glycobiologie et Matrice Extracellulaire, Normandie Université, Institute for Research and Innovation in Biomedicine, Végétal, Agronomie, Sol, et Innovation, 76821 Mont-Saint-Aignan, France (C.L., M.-C.K.-M., A.M., A.D., P.L., A.L., J.-C.M.);Unité Biologie des Plantes et Innovation (S.B., S.G., F.F., J.P.) and Centre de Ressources Régionales en Biologie Moléculaire (S.G.), Université de Picardie Jules Verne, 80039 Amiens, France; andInstitute of Plant Biology, University of Zürich, 8008 Zurich, Switzerland (T.N.F., C.R.)
| | - Patrice Lerouge
- Laboratoire Glycobiologie et Matrice Extracellulaire, Normandie Université, Institute for Research and Innovation in Biomedicine, Végétal, Agronomie, Sol, et Innovation, 76821 Mont-Saint-Aignan, France (C.L., M.-C.K.-M., A.M., A.D., P.L., A.L., J.-C.M.);Unité Biologie des Plantes et Innovation (S.B., S.G., F.F., J.P.) and Centre de Ressources Régionales en Biologie Moléculaire (S.G.), Université de Picardie Jules Verne, 80039 Amiens, France; andInstitute of Plant Biology, University of Zürich, 8008 Zurich, Switzerland (T.N.F., C.R.)
| | - Arnaud Lehner
- Laboratoire Glycobiologie et Matrice Extracellulaire, Normandie Université, Institute for Research and Innovation in Biomedicine, Végétal, Agronomie, Sol, et Innovation, 76821 Mont-Saint-Aignan, France (C.L., M.-C.K.-M., A.M., A.D., P.L., A.L., J.-C.M.);Unité Biologie des Plantes et Innovation (S.B., S.G., F.F., J.P.) and Centre de Ressources Régionales en Biologie Moléculaire (S.G.), Université de Picardie Jules Verne, 80039 Amiens, France; andInstitute of Plant Biology, University of Zürich, 8008 Zurich, Switzerland (T.N.F., C.R.)
| | - Jean-Claude Mollet
- Laboratoire Glycobiologie et Matrice Extracellulaire, Normandie Université, Institute for Research and Innovation in Biomedicine, Végétal, Agronomie, Sol, et Innovation, 76821 Mont-Saint-Aignan, France (C.L., M.-C.K.-M., A.M., A.D., P.L., A.L., J.-C.M.);Unité Biologie des Plantes et Innovation (S.B., S.G., F.F., J.P.) and Centre de Ressources Régionales en Biologie Moléculaire (S.G.), Université de Picardie Jules Verne, 80039 Amiens, France; andInstitute of Plant Biology, University of Zürich, 8008 Zurich, Switzerland (T.N.F., C.R.)
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97
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Buchnik L, Abu-Abied M, Sadot E. Role of plant myosins in motile organelles: is a direct interaction required? JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2015; 57:23-30. [PMID: 25196231 DOI: 10.1111/jipb.12282] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Accepted: 08/31/2014] [Indexed: 06/03/2023]
Abstract
Plant organelles are highly motile, with speed values of 3-7 µm/s in cells of land plants and about 20-60 µm/s in characean algal cells. This movement is believed to be important for rapid distribution of materials around the cell, for the plant's ability to respond to environmental biotic and abiotic signals and for proper growth. The main machinery that propels motility of organelles within plant cells is based on the actin cytoskeleton and its motor proteins the myosins. Most plants express multiple members of two main classes: myosin VIII and myosin XI. While myosin VIII has been characterized as a slow motor protein, myosins from class XI were found to be the fastest motor proteins known in all kingdoms. Paradoxically, while it was found that myosins from class XI regulate most organelle movement, it is not quite clear how or even if these motor proteins attach to the organelles whose movement they regulate.
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Affiliation(s)
- Limor Buchnik
- The Institute of Plant Sciences, The Volcani Center, ARO, PO Box 6, Bet-Dagan, 50250, Israel
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98
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Higashiyama T, Takeuchi H. The mechanism and key molecules involved in pollen tube guidance. ANNUAL REVIEW OF PLANT BIOLOGY 2015; 66:393-413. [PMID: 25621518 DOI: 10.1146/annurev-arplant-043014-115635] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
During sexual reproduction of flowering plants, pollen tube guidance by pistil tissue is critical for the delivery of nonmotile sperm cells to female gametes. Multistep controls of pollen tube guidance can be divided into two phases: preovular guidance and ovular guidance. During preovular guidance, various female molecules, including stimulants for pollen germination and pollen tube growth, are provided to support tube growth toward the ovary, where the ovules are located. After entering the ovary, pollen tubes receive directional cues from their respective target ovules, including attractant peptides for precise, species-preferential attraction. Successful pollen tube guidance in the pistil requires not only nutritional and directional controls but also competency controls to make pollen tubes responsive to guidance cues, regulation to terminate growth once a pollen tube arrives at the target, and strategies to stop ovular attraction depending on the fertilization of female gametes.
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99
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Lin D, Ren H, Fu Y. ROP GTPase-mediated auxin signaling regulates pavement cell interdigitation in Arabidopsis thaliana. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2015; 57:31-9. [PMID: 25168157 DOI: 10.1111/jipb.12281] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 08/27/2014] [Indexed: 05/08/2023]
Abstract
In multicellular plant organs, cell shape formation depends on molecular switches to transduce developmental or environmental signals and to coordinate cell-to-cell communication. Plants have a specific subfamily of the Rho GTPase family, usually called Rho of Plants (ROP), which serve as a critical signal transducer involved in many cellular processes. In the last decade, important advances in the ROP-mediated regulation of plant cell morphogenesis have been made by using Arabidopsis thaliana leaf and cotyledon pavement cells. Especially, the auxin-ROP signaling networks have been demonstrated to control interdigitated growth of pavement cells to form jigsaw-puzzle shapes. Here, we review findings related to the discovery of this novel auxin-signaling mechanism at the cell surface. This signaling pathway is to a large extent independent of the well-known Transport Inhibitor Response (TIR)-Auxin Signaling F-Box (AFB) pathway, and instead requires Auxin Binding Protein 1 (ABP1) interaction with the plasma membrane-localized, transmembrane kinase (TMK) receptor-like kinase to regulate ROP proteins. Once activated, ROP influences cytoskeletal organization and inhibits endocytosis of the auxin transporter PIN1. The present review focuses on ROP signaling and its self-organizing feature allowing ROP proteins to serve as a bustling signal decoder and integrator for plant cell morphogenesis.
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Affiliation(s)
- Deshu Lin
- Center for Genomics and Biotechnology, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
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Vogler F, Konrad SSA, Sprunck S. Knockin' on pollen's door: live cell imaging of early polarization events in germinating Arabidopsis pollen. FRONTIERS IN PLANT SCIENCE 2015; 6:246. [PMID: 25954283 PMCID: PMC4404733 DOI: 10.3389/fpls.2015.00246] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 03/27/2015] [Indexed: 05/20/2023]
Abstract
Pollen tubes are an excellent system for studying the cellular dynamics and complex signaling pathways that coordinate polarized tip growth. Although several signaling mechanisms acting in the tip-growing pollen tube have been described, our knowledge on the subcellular and molecular events during pollen germination and growth site selection at the pollen plasma membrane is rather scarce. To simultaneously track germinating pollen from up to 12 genetically different plants we developed an inexpensive and easy mounting technique, suitable for every standard microscope setup. We performed high magnification live-cell imaging during Arabidopsis pollen activation, germination, and the establishment of pollen tube tip growth by using fluorescent marker lines labeling either the pollen cytoplasm, vesicles, the actin cytoskeleton or the sperm cell nuclei and membranes. Our studies revealed distinctive vesicle and F-actin polarization during pollen activation and characteristic growth kinetics during pollen germination and pollen tube formation. Initially, the germinating Arabidopsis pollen tube grows slowly and forms a uniform roundish bulge, followed by a transition phase with vesicles heavily accumulating at the growth site before switching to rapid tip growth. Furthermore, we found the two sperm cells to be transported into the pollen tube after the phase of rapid tip growth has been initiated. The method presented here is suitable to quantitatively study subcellular events during Arabidopsis pollen germination and growth, and for the detailed analysis of pollen mutants with respect to pollen polarization, bulging, or growth site selection at the pollen plasma membrane.
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Affiliation(s)
- Frank Vogler
- Cell Biology and Plant Biochemistry, Biochemie-Zentrum RegensburgUniversity of Regensburg, Regensburg Germany
| | - Sebastian S. A. Konrad
- Faculty of Biology, Institute of Genetics, Ludwig-Maximilians-University of MunichMartinsried, Germany
| | - Stefanie Sprunck
- Cell Biology and Plant Biochemistry, Biochemie-Zentrum RegensburgUniversity of Regensburg, Regensburg Germany
- *Correspondence: Stefanie Sprunck, Department of Cell Biology and Plant Biochemistry, University of Regensburg, Universitaetsstrasse 31, 93053 Regensburg, Germany
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