1
|
Wang X, Li T, Xu J, Zhang F, Liu L, Wang T, Wang C, Ren H, Zhang Y. Distinct functions of microtubules and actin filaments in the transportation of the male germ unit in pollen. Nat Commun 2024; 15:5448. [PMID: 38937444 PMCID: PMC11211427 DOI: 10.1038/s41467-024-49323-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2023] [Accepted: 06/02/2024] [Indexed: 06/29/2024] Open
Abstract
Flowering plants rely on the polarized growth of pollen tubes to deliver sperm cells (SCs) to the embryo sac for double fertilization. In pollen, the vegetative nucleus (VN) and two SCs form the male germ unit (MGU). However, the mechanism underlying directional transportation of MGU is not well understood. In this study, we provide the first full picture of the dynamic interplay among microtubules, actin filaments, and MGU during pollen germination and tube growth. Depolymerization of microtubules and inhibition of kinesin activity result in an increased velocity and magnified amplitude of VN's forward and backward movement. Pharmacological washout experiments further suggest that microtubules participate in coordinating the directional movement of MGU. In contrast, suppression of the actomyosin system leads to a reduced velocity of VN mobility but without a moving pattern change. Moreover, detailed observation shows that the direction and velocity of VN's movement are in close correlations with those of the actomyosin-driven cytoplasmic streaming surrounding VN. Therefore, we propose that while actomyosin-based cytoplasmic streaming influences on the oscillational movement of MGU, microtubules and kinesins avoid MGU drifting with the cytoplasmic streaming and act as the major regulator for fine-tuning the proper positioning and directional migration of MGU in pollen.
Collapse
Affiliation(s)
- Xiangfei Wang
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Sciences, Beijing Normal University, 100875, Beijing, China
| | - Tonghui Li
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Sciences, Beijing Normal University, 100875, Beijing, China
| | - Jiuting Xu
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Sciences, Beijing Normal University, 100875, Beijing, China
| | - Fanfan Zhang
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Sciences, Beijing Normal University, 100875, Beijing, China
| | - Lifang Liu
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Sciences, Beijing Normal University, 100875, Beijing, China
| | - Ting Wang
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Sciences, Beijing Normal University, 100875, Beijing, China
| | - Chun Wang
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Sciences, Beijing Normal University, 100875, Beijing, China
| | - Haiyun Ren
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Sciences, Beijing Normal University, 100875, Beijing, China.
- Center for Biological Science and Technology, Guangdong Zhuhai-Macao Joint Biotech Laboratory, Beijing Normal University, 519087, Zhuhai, China.
| | - Yi Zhang
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Sciences, Beijing Normal University, 100875, Beijing, China.
| |
Collapse
|
2
|
Biswas R, Chaudhuri S. AtHMGB15 regulates tapetal apoptosis in pollen development and actin dynamics during pollen germination in arabidopsis. PLANT REPRODUCTION 2024:10.1007/s00497-024-00505-x. [PMID: 38904831 DOI: 10.1007/s00497-024-00505-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Accepted: 06/11/2024] [Indexed: 06/22/2024]
Abstract
KEY MESSAGE ARID-HMG DNA binding protein, AtHMGB15, regulates pollen development and pollen germination in Arabidopsis. Previous studies have shown that ARID-HMG DNA binding protein, AtHMGB15 regulate pollen development and pollen germination in Arabidopsis. Here, we performed transcriptome and cytological studies to understand the role of AtHMGB15 in regulating pollen wall morphology and the pollen tube germination rate. Our result showed abnormal vacuolization in the tapetal cells during anther maturation and prolonged PCD in AtHMGB15 loss-of-function mutant. The tapetum has the ability to perform both secretory and biosynthetic activities critical for pollen maturation and pollen viability. Interestingly, expression of PCD executer genes CEP1, MC9 and RNS3 were significant down-regulation of in athmgb15-4. The growth of pollen tubes is regulated by the actin cytoskeleton dynamics. To address the defect in pollen tube growth of athmgb15, we monitored the actin network in growing pollen tubes of wildtype and athmgb15-4 using Rhodamine-phalloidin fluorescence. Our results indicate a highly fragmented actin distribution in athmgb15-4 pollen tubes with a lesser number of long actin fibers and significantly low f-actin concentration at the apex. q-RTPCR further indicates significant downy-regulation of actin regulatory proteins VLN2 and PRF4. Collectively, our results suggest that AtHMGB15 being a nuclear architectural protein orchestrates high-order chromatin organization to promote the transcription of genes responsible for pollen development and pollen germination.
Collapse
Affiliation(s)
- Ruby Biswas
- Department of Biological Sciences, Bose Institute, Unified Academic Campus, EN 80, Sector V, Bidhan Nagar, Kolkata, West Bengal, 700091, India
| | - Shubho Chaudhuri
- Department of Biological Sciences, Bose Institute, Unified Academic Campus, EN 80, Sector V, Bidhan Nagar, Kolkata, West Bengal, 700091, India.
| |
Collapse
|
3
|
Del Casino C, Conti V, Licata S, Cai G, Cantore A, Ricci C, Cantara S. Mitigation of UV-B Radiation Stress in Tobacco Pollen by Expression of the Tardigrade Damage Suppressor Protein (Dsup). Cells 2024; 13:840. [PMID: 38786062 PMCID: PMC11119994 DOI: 10.3390/cells13100840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2024] [Revised: 04/19/2024] [Accepted: 04/23/2024] [Indexed: 05/25/2024] Open
Abstract
Pollen, the male gametophyte of seed plants, is extremely sensitive to UV light, which may prevent fertilization. As a result, strategies to improve plant resistance to solar ultraviolet (UV) radiation are required. The tardigrade damage suppressor protein (Dsup) is a putative DNA-binding protein that enables tardigrades to tolerate harsh environmental conditions, including UV radiation, and was therefore considered as a candidate for reducing the effects of UV exposure on pollen. Tobacco pollen was genetically engineered to express Dsup and then exposed to UV-B radiation to determine the effectiveness of the protein in increasing pollen resistance. To establish the preventive role of Dsup against UV-B stress, we carried out extensive investigations into pollen viability, germination rate, pollen tube length, male germ unit position, callose plug development, marker protein content, and antioxidant capacity. The results indicated that UV-B stress has a significant negative impact on both pollen grain and pollen tube growth. However, Dsup expression increased the antioxidant levels and reversed some of the UV-B-induced changes to pollen, restoring the proper distance between the tip and the last callose plug formed, as well as pollen tube length, tubulin, and HSP70 levels. Therefore, the expression of heterologous Dsup in pollen may provide the plant male gametophyte with enhanced responses to UV-B stress and protection against harmful environmental radiation.
Collapse
Affiliation(s)
- Cecilia Del Casino
- Dipartimento di Scienze della Vita, University of Siena, via Mattioli 4, 53100 Siena, Italy; (C.D.C.); (S.L.)
| | - Veronica Conti
- Dipartimento di Scienze Biologiche, Geologiche e Ambientali, Università di Bologna, via Irnerio 42, 40126 Bologna, Italy;
| | - Silvia Licata
- Dipartimento di Scienze della Vita, University of Siena, via Mattioli 4, 53100 Siena, Italy; (C.D.C.); (S.L.)
| | - Giampiero Cai
- Dipartimento di Scienze della Vita, University of Siena, via Mattioli 4, 53100 Siena, Italy; (C.D.C.); (S.L.)
| | - Anna Cantore
- Department of Medical, Surgical and Neurological Sciences, University of Siena, Viale Bracci, 53100 Siena, Italy; (A.C.); (C.R.); (S.C.)
| | - Claudia Ricci
- Department of Medical, Surgical and Neurological Sciences, University of Siena, Viale Bracci, 53100 Siena, Italy; (A.C.); (C.R.); (S.C.)
| | - Silvia Cantara
- Department of Medical, Surgical and Neurological Sciences, University of Siena, Viale Bracci, 53100 Siena, Italy; (A.C.); (C.R.); (S.C.)
| |
Collapse
|
4
|
Weng X, Shen Y, Jiang L, Zhao L, Wang H. Spatiotemporal organization and correlation of tip-focused exocytosis and endocytosis in regulating pollen tube tip growth. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2023; 330:111633. [PMID: 36775070 DOI: 10.1016/j.plantsci.2023.111633] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 01/09/2023] [Accepted: 02/07/2023] [Indexed: 06/18/2023]
Abstract
Pollen tube polar growth is a key cellular process during plant fertilization and is regulated by tip-focused exocytosis and endocytosis. However, the spatiotemporal dynamics and localizations of apical exocytosis and endocytosis in the tip region are still a matter of debate. Here, we use a refined spinning-disk confocal microscope coupled with fluorescence recovery after photobleaching for sustained live imaging and quantitative analysis of rapid vesicular activities in growing pollen tube tips. We traced and analyzed the occurrence site of exocytic plasma membrane-targeting of Arabidopsis secretory carrier membrane protein 4 and its subsequent endocytosis in tobacco pollen tube tips. We demonstrated that the pollen tube apex is the site for both vesicle polar exocytic fusion and endocytosis to take place. In addition, we disrupted either tip-focused exocytosis or endocytosis and found that their dynamic activities are closely correlated with one another basing on the spatial organization of actin fringe. Collectively, our findings attempt to propose a new exocytosis and endocytosis-coordinated yin-yang working model underlying the apical membrane organization and dynamics during pollen tube tip growth.
Collapse
Affiliation(s)
- Xun Weng
- College of Life Sciences, South China Agricultural University, Guangzhou 510642, China
| | - Yifan Shen
- Utahloy International School of Guangzhou, Guangzhou 510642, China
| | - Liwen Jiang
- School of Life Sciences, Centre for Cell and Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China; Institute of Plant Molecular Biology & Agricultural Biotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Lifeng Zhao
- College of Life Sciences, South China Agricultural University, Guangzhou 510642, China.
| | - Hao Wang
- College of Life Sciences, South China Agricultural University, Guangzhou 510642, China.
| |
Collapse
|
5
|
Hong WJ, Kim EJ, Yoon J, Silva J, Moon S, Min CW, Cho LH, Kim ST, Park SK, Kim YJ, Jung KH. A myosin XI adaptor, TAPE, is essential for pollen tube elongation in rice. PLANT PHYSIOLOGY 2022; 190:562-575. [PMID: 35736513 PMCID: PMC9434255 DOI: 10.1093/plphys/kiac299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 05/30/2022] [Indexed: 06/15/2023]
Abstract
Pollen tube (PT) elongation is important for double fertilization in angiosperms and affects the seed-setting rate and, therefore, crop productivity. Compared to Arabidopsis (Arabidopsis thaliana L.), information on PT elongation in rice (Oryza sativa L.) is limited by the difficulty in obtaining homozygous mutants. In a screen of T-DNA insertional mutants, we identified a mutant in the Tethering protein of actomyosin transport in pollen tube elongation (TAPE) gene with an unusual segregation ratio by genotyping analysis. A CRISPR/Cas9 knockout mutant of TAPE that produced a short PT was sterile, and TAPE was expressed specifically in pollen grains. TAPE is a homolog of a myosin XI adaptor in Arabidopsis with three tetratricopeptide repeat and Phox and Bem1 protein domains. TAPE showed latrunculin B-sensitive, actin-dependent localization to the endoplasmic reticulum. Yeast two-hybrid screening and transcriptome analysis revealed that TAPE interacted with pollen-specific LIM protein 2b and elongation factor 1-alpha. Loss of TAPE affected transcription of 1,259 genes, especially genes related to cell organization, which were downregulated. In summary, TAPE encodes a myosin XI adaptor essential for rice PT elongation.
Collapse
Affiliation(s)
- Woo-Jong Hong
- Graduate School of Green-Bio Science & Crop Biotech Institute, Kyung Hee University, Yongin, 17104, Republic of Korea
| | - Eui-Jung Kim
- Graduate School of Green-Bio Science & Crop Biotech Institute, Kyung Hee University, Yongin, 17104, Republic of Korea
| | - Jinmi Yoon
- Department of Plant Bioscience, Pusan National University, Miryang, 50463, Republic of Korea
| | - Jeniffer Silva
- Graduate School of Green-Bio Science & Crop Biotech Institute, Kyung Hee University, Yongin, 17104, Republic of Korea
| | - Sunok Moon
- Graduate School of Green-Bio Science & Crop Biotech Institute, Kyung Hee University, Yongin, 17104, Republic of Korea
| | - Cheol Woo Min
- Department of Plant Bioscience, Pusan National University, Miryang, 50463, Republic of Korea
| | - Lae-Hyeon Cho
- Department of Plant Bioscience, Pusan National University, Miryang, 50463, Republic of Korea
| | - Sun Tae Kim
- Department of Plant Bioscience, Pusan National University, Miryang, 50463, Republic of Korea
| | - Soon Ki Park
- School of Applied Biosciences, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Yu-Jin Kim
- Authors for correspondence: (Y.-J.K.); (K.-H.J.)
| | - Ki-Hong Jung
- Authors for correspondence: (Y.-J.K.); (K.-H.J.)
| |
Collapse
|
6
|
Westermann J. Two Is Company, but Four Is a Party-Challenges of Tetraploidization for Cell Wall Dynamics and Efficient Tip-Growth in Pollen. PLANTS (BASEL, SWITZERLAND) 2021; 10:plants10112382. [PMID: 34834745 PMCID: PMC8623246 DOI: 10.3390/plants10112382] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 11/01/2021] [Accepted: 11/03/2021] [Indexed: 05/27/2023]
Abstract
Some cells grow by an intricately coordinated process called tip-growth, which allows the formation of long tubular structures by a remarkable increase in cell surface-to-volume ratio and cell expansion across vast distances. On a broad evolutionary scale, tip-growth has been extraordinarily successful, as indicated by its recurrent 're-discovery' throughout evolutionary time in all major land plant taxa which allowed for the functional diversification of tip-growing cell types across gametophytic and sporophytic life-phases. All major land plant lineages have experienced (recurrent) polyploidization events and subsequent re-diploidization that may have positively contributed to plant adaptive evolutionary processes. How individual cells respond to genome-doubling on a shorter evolutionary scale has not been addressed as elaborately. Nevertheless, it is clear that when polyploids first form, they face numerous important challenges that must be overcome for lineages to persist. Evidence in the literature suggests that tip-growth is one of those processes. Here, I discuss the literature to present hypotheses about how polyploidization events may challenge efficient tip-growth and strategies which may overcome them: I first review the complex and multi-layered processes by which tip-growing cells maintain their cell wall integrity and steady growth. I will then discuss how they may be affected by the cellular changes that accompany genome-doubling. Finally, I will depict possible mechanisms polyploid plants may evolve to compensate for the effects caused by genome-doubling to regain diploid-like growth, particularly focusing on cell wall dynamics and the subcellular machinery they are controlled by.
Collapse
Affiliation(s)
- Jens Westermann
- Institute of Molecular Plant Biology, Department of Biology, ETH Zürich, Universitätsstrasse 2, 8092 Zürich, Switzerland
| |
Collapse
|
7
|
Bibeau JP, Galotto G, Wu M, Tüzel E, Vidali L. Quantitative cell biology of tip growth in moss. PLANT MOLECULAR BIOLOGY 2021; 107:227-244. [PMID: 33825083 PMCID: PMC8492783 DOI: 10.1007/s11103-021-01147-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 03/25/2021] [Indexed: 05/16/2023]
Abstract
KEY MESSAGE Here we review, from a quantitative point of view, the cell biology of protonemal tip growth in the model moss Physcomitrium patens. We focus on the role of the cytoskeleton, vesicle trafficking, and cell wall mechanics, including reviewing some of the existing mathematical models of tip growth. We provide a primer for existing cell biological tools that can be applied to the future study of tip growth in moss. Polarized cell growth is a ubiquitous process throughout the plant kingdom in which the cell elongates in a self-similar manner. This process is important for nutrient uptake by root hairs, fertilization by pollen, and gametophyte development by the protonemata of bryophytes and ferns. In this review, we will focus on the tip growth of moss cells, emphasizing the role of cytoskeletal organization, cytoplasmic zonation, vesicle trafficking, cell wall composition, and dynamics. We compare some of the existing knowledge on tip growth in protonemata against what is known in pollen tubes and root hairs, which are better-studied tip growing cells. To fully understand how plant cells grow requires that we deepen our knowledge in a variety of forms of plant cell growth. We focus this review on the model plant Physcomitrium patens, which uses tip growth as the dominant form of growth at its protonemal stage. Because mosses and vascular plants shared a common ancestor more than 450 million years ago, we anticipate that both similarities and differences between tip growing plant cells will provide mechanistic information of tip growth as well as of plant cell growth in general. Towards this mechanistic understanding, we will also review some of the existing mathematical models of plant tip growth and their applicability to investigate protonemal morphogenesis. We attempt to integrate the conclusions and data across cell biology and physical modeling to our current state of knowledge of polarized cell growth in P. patens and highlight future directions in the field.
Collapse
Affiliation(s)
- Jeffrey P Bibeau
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA, USA
| | - Giulia Galotto
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA, USA
| | - Min Wu
- Department of Mathematical Sciences, Worcester Polytechnic Institute, Worcester, MA, USA
- Bioinformatics and Computational Biology Program, Worcester Polytechnic Institute, Worcester, MA, USA
| | - Erkan Tüzel
- Bioengineering Department, Temple University, Philadelphia, PA, USA
| | - Luis Vidali
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA, USA.
- Bioinformatics and Computational Biology Program, Worcester Polytechnic Institute, Worcester, MA, USA.
| |
Collapse
|
8
|
Tian X, Wang X, Li Y. Myosin XI-B is involved in the transport of vesicles and organelles in pollen tubes of Arabidopsis thaliana. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 108:1145-1161. [PMID: 34559914 DOI: 10.1111/tpj.15505] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 09/09/2021] [Accepted: 09/14/2021] [Indexed: 06/13/2023]
Abstract
The movement of organelles and vesicles in pollen tubes depends on F-actin. However, the molecular mechanism through which plant myosin XI drives the movement of organelles is still controversial, and the relationship between myosin XI and vesicle movement in pollen tubes is also unclear. In this study, we found that the siliques of the myosin xi-b/e mutant were obviously shorter than those of the wild-type (WT) and that the seed set of the mutant was severely deficient. The pollen tube growth of myosin xi-b/e was significantly inhibited both in vitro and in vivo. Fluorescence recovery after photobleaching showed that the velocity of vesicle movement in the pollen tube tip of the myosin xi-b/e mutant was lower than that of the WT. It was also found that peroxisome movement was significantly inhibited in the pollen tubes of the myosin xi-b/e mutant, while the velocities of the Golgi stack and mitochondrial movement decreased relatively less in the pollen tubes of the mutant. The endoplasmic reticulum streaming in the pollen tube shanks was not significantly different between the WT and the myosin xi-b/e mutant. In addition, we found that myosin XI-B-GFP colocalized obviously with vesicles and peroxisomes in the pollen tubes of Arabidopsis. Taken together, these results indicate that myosin XI-B may bind mainly to vesicles and peroxisomes, and drive their movement in pollen tubes. These results also suggest that the mechanism by which myosin XI drives organelle movement in plant cells may be evolutionarily conserved compared with other eukaryotic cells.
Collapse
Affiliation(s)
- Xiulin Tian
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Xingjuan Wang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Yan Li
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| |
Collapse
|
9
|
Breygina M, Klimenko E, Schekaleva O. Pollen Germination and Pollen Tube Growth in Gymnosperms. PLANTS (BASEL, SWITZERLAND) 2021; 10:1301. [PMID: 34206892 PMCID: PMC8309077 DOI: 10.3390/plants10071301] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 06/18/2021] [Accepted: 06/23/2021] [Indexed: 01/08/2023]
Abstract
Pollen germination and pollen tube growth are common to all seed plants, but these processes first developed in gymnosperms and still serve for their successful sexual reproduction. The main body of data on the reproductive physiology, however, was obtained on flowering plants, and one should be careful to extrapolate the discovered patterns to gymnosperms. In recent years, physiological studies of coniferous pollen have been increasing, and both the features of this group and the similarities with flowering plants have already been identified. The main part of the review is devoted to physiological studies carried out on conifer pollen. The main properties and diversity of pollen grains and pollination strategies in gymnosperms are described.
Collapse
Affiliation(s)
- Maria Breygina
- Department of Plant Physiology, Biological Faculty, Lomonosov Moscow State University, 119991 Moscow, Russia; (E.K.); (O.S.)
| | | | | |
Collapse
|
10
|
Abstract
The plant cell wall is an extracellular matrix that envelopes cells, gives them structure and shape, constitutes the interface with symbionts, and defends plants against external biotic and abiotic stress factors. The assembly of this matrix is regulated and mediated by the cytoskeleton. Cytoskeletal elements define where new cell wall material is added and how fibrillar macromolecules are oriented in the wall. Inversely, the cytoskeleton is also key in the perception of mechanical cues generated by structural changes in the cell wall as well as the mediation of intracellular responses. We review the delivery processes of the cell wall precursors that are required for the cell wall assembly process and the structural continuity between the inside and the outside of the cell. We provide an overview of the different morphogenetic processes for which cell wall assembly is a crucial element and elaborate on relevant feedback mechanisms.
Collapse
|
11
|
Duan X, Chen X, Wang K, Chen L, Glomb O, Johnsson N, Feng L, Zhou XQ, Bi E. Essential role of the endocytic site-associated protein Ecm25 in stress-induced cell elongation. Cell Rep 2021; 35:109122. [PMID: 34010635 PMCID: PMC8202958 DOI: 10.1016/j.celrep.2021.109122] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 02/16/2021] [Accepted: 04/22/2021] [Indexed: 11/27/2022] Open
Abstract
How cells adopt a different morphology to cope with stress is not well understood. Here, we show that budding yeast Ecm25 associates with polarized endocytic sites and interacts with the polarity regulator Cdc42 and several late-stage endocytic proteins via distinct regions, including an actin filament-binding motif. Deletion of ECM25 does not affect Cdc42 activity or cause any strong defects in fluid-phase and clathrin-mediated endocytosis but completely abolishes hydroxyurea-induced cell elongation. This phenotype is accompanied by depolarization of the spatiotemporally coupled exo-endocytosis in the bud cortex while maintaining the overall mother-bud polarity. These data suggest that Ecm25 provides an essential link between the polarization signal and the endocytic machinery to enable adaptive morphogenesis under stress conditions. How cells adopt a different morphology to cope with stress is not well understood. Duan et al. report that the budding yeast protein Ecm25 plays an essential role in stress-induced cell elongation by linking the polarity regulator Cdc42 to the late-stage endocytic machinery.
Collapse
Affiliation(s)
- Xudong Duan
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6058, USA; Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, 611130 Sichuan, China; Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
| | - Xi Chen
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6058, USA
| | - Kangji Wang
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6058, USA
| | - Li Chen
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6058, USA
| | - Oliver Glomb
- Institut für Molekulare Genetik und Zellbiologie, Universität Ulm, 89081 Ulm, Germany
| | - Nils Johnsson
- Institut für Molekulare Genetik und Zellbiologie, Universität Ulm, 89081 Ulm, Germany
| | - Lin Feng
- Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, 611130 Sichuan, China
| | - Xiao-Qiu Zhou
- Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, 611130 Sichuan, China.
| | - Erfei Bi
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6058, USA.
| |
Collapse
|
12
|
Schattner S, Schattner J, Munder F, Höppe E, Walter WJ. A Tug-of-War Model Explains the Saltatory Sperm Cell Movement in Arabidopsis thaliana Pollen Tubes by Kinesins With Calponin Homology Domain. FRONTIERS IN PLANT SCIENCE 2021; 11:601282. [PMID: 33664751 PMCID: PMC7921805 DOI: 10.3389/fpls.2020.601282] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 12/28/2020] [Indexed: 05/16/2023]
Abstract
Upon pollination, two sperm cells are transported inside the growing pollen tube toward the apex. One sperm cell fertilizes the egg cell to form the zygote, while the other fuses with the two polar nuclei to form the triploid endosperm. In Arabidopsis thaliana, the transport of the two sperm cells is characterized by sequential forward and backward movements with intermediate pauses. Until now, it is under debate which components of the plant cytoskeleton govern this mechanism. The sperm cells are interconnected and linked to the vegetative nucleus via a cytoplasmic projection, thus forming the male germ unit. This led to the common hypothesis that the vegetative nucleus is actively transported via myosin motors along actin cables while pulling along the sperm cells as passive cargo. In this study, however, we show that upon occasional germ unit disassembly, the sperm cells are transported independently and still follow the same bidirectional movement pattern. Moreover, we found that the net movement of sperm cells results from a combination of both longer and faster runs toward the pollen tube apex. We propose that the observed saltatory movement can be explained by the function of kinesins with calponin homology domain (KCH). This subgroup of the kinesin-14 family actively links actin filaments and microtubules. Based on KCH's specific properties derived from in vitro experiments, we built a tug-of-war model that could reproduce the characteristic sperm cell movement in pollen tubes.
Collapse
Affiliation(s)
- Saskia Schattner
- Department of Biology, Institute for Plant Science and Microbiology, University of Hamburg, Hamburg, Germany
| | - Jan Schattner
- Department of Biology, Institute for Plant Science and Microbiology, University of Hamburg, Hamburg, Germany
| | - Fabian Munder
- Department of Biology, Institute for Plant Science and Microbiology, University of Hamburg, Hamburg, Germany
| | - Eva Höppe
- Department of Biology, Institute for Plant Science and Microbiology, University of Hamburg, Hamburg, Germany
| | - Wilhelm J. Walter
- Department of Biology, Institute for Plant Science and Microbiology, University of Hamburg, Hamburg, Germany
- Department Medicine, Health and Medical University Potsdam, Potsdam, Germany
| |
Collapse
|
13
|
Xu Y, Huang S. Control of the Actin Cytoskeleton Within Apical and Subapical Regions of Pollen Tubes. Front Cell Dev Biol 2020; 8:614821. [PMID: 33344460 PMCID: PMC7744591 DOI: 10.3389/fcell.2020.614821] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 11/13/2020] [Indexed: 01/07/2023] Open
Abstract
In flowering plants, sexual reproduction involves a double fertilization event, which is facilitated by the delivery of two non-motile sperm cells to the ovule by the pollen tube. Pollen tube growth occurs exclusively at the tip and is extremely rapid. It strictly depends on an intact actin cytoskeleton, and is therefore an excellent model for uncovering the molecular mechanisms underlying dynamic actin cytoskeleton remodeling. There has been a long-term debate about the organization and dynamics of actin filaments within the apical and subapical regions of pollen tube tips. By combining state-of-the-art live-cell imaging with the usage of mutants which lack different actin-binding proteins, our understanding of the origin, spatial organization, dynamics and regulation of actin filaments within the pollen tube tip has greatly improved. In this review article, we will summarize the progress made in this area.
Collapse
Affiliation(s)
| | - Shanjin Huang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
| |
Collapse
|
14
|
Wang X, Sheng X, Tian X, Zhang Y, Li Y. Organelle movement and apical accumulation of secretory vesicles in pollen tubes of Arabidopsis thaliana depend on class XI myosins. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 104:1685-1697. [PMID: 33067901 DOI: 10.1111/tpj.15030] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 09/12/2020] [Accepted: 09/18/2020] [Indexed: 06/11/2023]
Abstract
F-actin and myosin XI play important roles in plant organelle movement. A few myosin XI genes in the genome of Arabidopsis are mainly expressed in mature pollen, which suggests that they may play a crucial role in pollen germination and pollen tube tip growth. In this study, a genetic complementation assay was conducted in a myosin xi-c (myo11c1) myosin xi-e (myo11c2) double mutant, and fluorescence labeling combined with microscopic observation was applied. We found that myosin XI-E (Myo11C2)-green fluorescent protein (GFP) restored the slow pollen tube growth and seed deficiency phenotypes of the myo11c1 myo11c2 double mutant and Myo11C2-GFP partially colocalized with mitochondria, peroxisomes and Golgi stacks. Furthermore, decreased mitochondrial movement and subapical accumulation were detected in myo11c1 myo11c2 double mutant pollen tubes. Fluorescence recovery after photobleaching experiments showed that the fluorescence recoveries of GFP-RabA4d and AtPRK1-GFP at the pollen tube tip of the myo11c1 myo11c2 double mutant were lower than those of the wild type were after photobleaching. These results suggest that Myo11C2 may be associated with mitochondria, peroxisomes and Golgi stacks, and play a crucial role in organelle movement and apical accumulation of secretory vesicles in pollen tubes of Arabidopsis thaliana.
Collapse
Affiliation(s)
- Xingjuan Wang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Xiaojing Sheng
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Xiulin Tian
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Yu Zhang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Yan Li
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| |
Collapse
|
15
|
Adhikari PB, Liu X, Kasahara RD. Mechanics of Pollen Tube Elongation: A Perspective. FRONTIERS IN PLANT SCIENCE 2020; 11:589712. [PMID: 33193543 PMCID: PMC7606272 DOI: 10.3389/fpls.2020.589712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 09/30/2020] [Indexed: 05/13/2023]
Abstract
Pollen tube (PT) serves as a vehicle that delivers male gametes (sperm cells) to a female gametophyte during double fertilization, which eventually leads to the seed formation. It is one of the fastest elongating structures in plants. Normally, PTs traverse through the extracellular matrix at the transmitting tract after penetrating the stigma. While the endeavor may appear simple, the molecular processes and mechanics of the PT elongation is yet to be fully resolved. Although it is the most studied "tip-growing" structure in plants, several features of the structure (e.g., Membrane dynamics, growth behavior, mechanosensing etc.) are only partially understood. In many aspects, PTs are still considered as a tissue rather than a "unique cell." In this review, we have attempted to discuss mainly on the mechanics behind PT-elongation and briefly on the molecular players involved in the process. Four aspects of PTs are particularly discussed: the PT as a cell, its membrane dynamics, mechanics of its elongation, and the potential mechanosensors involved in its elongation based on relevant findings in both plant and non-plant models.
Collapse
Affiliation(s)
- Prakash Babu Adhikari
- School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
- Horticultural Plant Biology and Metabolomics Center (HBMC), Fujian Agriculture and Forestry University, Fuzhou, China
| | - Xiaoyan Liu
- School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
- Horticultural Plant Biology and Metabolomics Center (HBMC), Fujian Agriculture and Forestry University, Fuzhou, China
| | - Ryushiro D. Kasahara
- School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
- Horticultural Plant Biology and Metabolomics Center (HBMC), Fujian Agriculture and Forestry University, Fuzhou, China
| |
Collapse
|
16
|
Duan Z, Tanaka M, Kanazawa T, Haraguchi T, Takyu A, Era A, Ueda T, Ito K, Tominaga M. Characterization of ancestral myosin XI from Marchantia polymorpha by heterologous expression in Arabidopsis thaliana. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 104:460-473. [PMID: 32717107 PMCID: PMC7689712 DOI: 10.1111/tpj.14937] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 07/16/2020] [Indexed: 05/30/2023]
Abstract
Previous studies have revealed duplications and diversification of myosin XI genes between angiosperms and bryophytes; however, the functional differentiation and conservation of myosin XI between them remain unclear. Here, we identified a single myosin XI gene from the liverwort Marchantia polymorpha (Mp). The molecular properties of Mp myosin XI are similar to those of Arabidopsis myosin XIs responsible for cytoplasmic streaming, suggesting that the motor function of myosin XI is able to generate cytoplasmic streaming. In cultured Arabidopsis cells, transiently expressed green fluorescent protein (GFP)-fused Mp myosin XI was observed as some intracellular structures moving along the F-actin. These intracellular structures were co-localized with motile endoplasmic reticulum (ER) strands, suggesting that Mp myosin XI binds to the ER and generates intracellular transport in Arabidopsis cells. The tail domain of Mp myosin XI was co-localized with that of Arabidopsis myosin XI-2 and XI-K, suggesting that all these myosin XIs bind to common cargoes. Furthermore, expression of GFP-fused Mp myosin XI rescued the defects of growth, cytoplasmic streaming and actin organization in Arabidopsis multiple myosin XI knockout mutants. The heterologous expression experiments demonstrated the cellular and physiological competence of Mp myosin XI in Arabidopsis. However, the average velocity of organelle transport in Marchantia rhizoids was 0.04 ± 0.01 μm s-1 , which is approximately one-hundredth of that in Arabidopsis cells. Taken together, our results suggest that the molecular properties of myosin XI are conserved, but myosin XI-driven intracellular transport in vivo would be differentiated from bryophytes to angiosperms.
Collapse
Affiliation(s)
- Zhongrui Duan
- Faculty of Education and Integrated Arts and SciencesWaseda University2‐2 Wakamatsu‐cho, Shinjuku‐kuTokyo162‐8480Japan
| | - Misato Tanaka
- Graduate School of Science and EngineeringWaseda University2‐2 Wakamatsu‐cho, Shinjuku‐kuTokyo162‐8480Japan
| | - Takehiko Kanazawa
- Division of Cellular DynamicsNational Institute for Basic BiologyNishigonaka 38, MyodaijiOkazakiAichi444‐8585Japan
- Department of Basic BiologySOKENDAINishigonaka 38, MyodaijiOkazakiAichi444‐8585Japan
| | - Takeshi Haraguchi
- Department of BiologyGraduate School of ScienceChiba UniversityInage‐kuChiba263‐8522Japan
| | - Akiko Takyu
- Department of BiologyGraduate School of ScienceChiba UniversityInage‐kuChiba263‐8522Japan
| | - Atsuko Era
- Department of Biological SciencesGraduate School of ScienceThe University of TokyoBunkyo‐kuTokyo113‐0033Japan
| | - Takashi Ueda
- Division of Cellular DynamicsNational Institute for Basic BiologyNishigonaka 38, MyodaijiOkazakiAichi444‐8585Japan
- Department of Basic BiologySOKENDAINishigonaka 38, MyodaijiOkazakiAichi444‐8585Japan
| | - Kohji Ito
- Department of BiologyGraduate School of ScienceChiba UniversityInage‐kuChiba263‐8522Japan
| | - Motoki Tominaga
- Faculty of Education and Integrated Arts and SciencesWaseda University2‐2 Wakamatsu‐cho, Shinjuku‐kuTokyo162‐8480Japan
- Graduate School of Science and EngineeringWaseda University2‐2 Wakamatsu‐cho, Shinjuku‐kuTokyo162‐8480Japan
| |
Collapse
|
17
|
Li W, Wu H, Li X, Chen Y, Yin T. Fine mapping of the sex locus in Salix triandra confirms a consistent sex determination mechanism in genus Salix. HORTICULTURE RESEARCH 2020; 7:64. [PMID: 32377355 PMCID: PMC7193568 DOI: 10.1038/s41438-020-0289-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 02/27/2020] [Accepted: 03/02/2020] [Indexed: 05/19/2023]
Abstract
Salix triandra belongs to section Amygdalinae in genus Salix, which is in a different section from the willow species in which sex determination has been well studied. Studying sex determination in distantly related willow species will help to clarify whether the sexes of different willows arise through a common sex determination system. For this purpose, we generated an intraspecific full-sib F1 population for S. triandra and constructed high-density genetic linkage maps for the crossing parents using restriction site-associated DNA sequencing and following a two-way pseudo-testcross strategy. With the established maps, the sex locus was positioned in linkage group XV only in the maternal map, and no sex linkage was detected in the paternal map. Consistent with previous findings in other willow species, our study showed that chromosome XV was the incipient sex chromosome and that females were the heterogametic sex in S. triandra. Therefore, sex in this willow species is also determined through a ZW sex determination system. We further performed fine mapping in the vicinity of the sex locus with SSR markers. By comparing the physical and genetic distances for the target interval encompassing the sex determination gene confined by SSRs, severe recombination repression was revealed in the sex determination region in the female map. The recombination rate in the confined interval encompassing the sex locus was approximately eight-fold lower than the genome-wide average. This study provides critical information relevant to sex determination in S. triandra.
Collapse
Affiliation(s)
- Wei Li
- The Key Lab of Cultivar Innovation and Germplasm Improvement of Salicaceae, College of Forestry, Nanjing Forestry University, Nanjing, 210037 China
| | - Huaitong Wu
- The Key Lab of Cultivar Innovation and Germplasm Improvement of Salicaceae, College of Forestry, Nanjing Forestry University, Nanjing, 210037 China
| | - Xiaoping Li
- The Key Lab of Cultivar Innovation and Germplasm Improvement of Salicaceae, College of Forestry, Nanjing Forestry University, Nanjing, 210037 China
| | - Yingnan Chen
- The Key Lab of Cultivar Innovation and Germplasm Improvement of Salicaceae, College of Forestry, Nanjing Forestry University, Nanjing, 210037 China
| | - Tongming Yin
- The Key Lab of Cultivar Innovation and Germplasm Improvement of Salicaceae, College of Forestry, Nanjing Forestry University, Nanjing, 210037 China
| |
Collapse
|
18
|
González-Gutiérrez AG, Verdín J, Rodríguez-Garay B. Simple Whole-Mount Staining Protocol of F-Actin for Studies of the Female Gametophyte in Agavoideae and Other Crassinucellate Ovules. FRONTIERS IN PLANT SCIENCE 2020; 11:384. [PMID: 32328076 PMCID: PMC7161591 DOI: 10.3389/fpls.2020.00384] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 03/17/2020] [Indexed: 05/28/2023]
Abstract
During plant sexual reproduction, F-actin takes part in the elongation of the pollen tube and the movement of sperm cells along with it. Moreover, F-actin is involved in the transport of sperm cells throughout the embryo sac when double fertilization occurs. Different techniques for analysis of F-actin in plant cells have been developed: from classical actin-immunolocalization in fixed tissues to genetically tagged actin with fluorescent proteins for live imaging of cells. Despite the implementation of live cell imaging tools, fixed plant tissue methods for cytoskeletal studies remain an essential tool for genetically intractable systems. Also, most of the work on live imaging of the cytoskeleton has been conducted on cells located on the plant's surface, such as epidermal cells, trichomes, and root hairs. In cells situated in the plant's interior, especially those from plant species with thicker organ systems, it is necessary to utilize conventional sectioning and permeabilization methods to allow the label access to the cytoskeleton. Studies about the role of F-actin cytoskeleton during double fertilization in plants with crassinucellate ovules (e.g., Agave, Yucca, Polianthes, Prochnyantes, and Manfreda) remain scarce due to the difficulties to access the female gametophyte. Here, we have developed a straightforward method for analysis of F-actin in the female gametophyte of different Agavoideae sub-family species. The procedure includes the fixation of whole ovules with formaldehyde, followed by membrane permeabilization with cold acetone, a prolonged staining step with rhodamine-phalloidin, and Hoechst 33342 as a counterstain and two final steps of dehydration of samples in increasing-concentration series of cold isopropanol and clarification of tissues with methyl salicylate. This technique allows the analysis of a large number of samples in a short period, cell positioning relative to neighbor cells is maintained, and, with the help of a confocal microscope, reconstruction of a single 3D image of F-actin structures into the embryo sac can be obtained.
Collapse
Affiliation(s)
- Alejandra G González-Gutiérrez
- Unidad de Biotecnología Vegetal, CIATEJ, Centro de Investigación y Asistencia en Tecnología y Diseño del Estado de Jalisco, A.C., Zapopan, Mexico
| | - Jorge Verdín
- Unidad de Biotecnología Industrial, CIATEJ, Centro de Investigación y Asistencia en Tecnología y Diseño del Estado de Jalisco, A.C., Zapopan, Mexico
| | - Benjamín Rodríguez-Garay
- Unidad de Biotecnología Vegetal, CIATEJ, Centro de Investigación y Asistencia en Tecnología y Diseño del Estado de Jalisco, A.C., Zapopan, Mexico
| |
Collapse
|
19
|
Zhou R, Macaya-Sanz D, Rodgers-Melnick E, Carlson CH, Gouker FE, Evans LM, Schmutz J, Jenkins JW, Yan J, Tuskan GA, Smart LB, DiFazio SP. Characterization of a large sex determination region in Salix purpurea L. (Salicaceae). Mol Genet Genomics 2018; 293:1437-1452. [PMID: 30022352 DOI: 10.1007/s00438-018-1473-y] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 07/09/2018] [Indexed: 12/30/2022]
Abstract
Dioecy has evolved numerous times in plants, but heteromorphic sex chromosomes are apparently rare. Sex determination has been studied in multiple Salix and Populus (Salicaceae) species, and P. trichocarpa has an XY sex determination system on chromosome 19, while S. suchowensis and S. viminalis have a ZW system on chromosome 15. Here we use whole genome sequencing coupled with quantitative trait locus mapping and a genome-wide association study to characterize the genomic composition of the non-recombining portion of the sex determination region. We demonstrate that Salix purpurea also has a ZW system on chromosome 15. The sex determination region has reduced recombination, high structural polymorphism, an abundance of transposable elements, and contains genes that are involved in sex expression in other plants. We also show that chromosome 19 contains sex-associated markers in this S. purpurea assembly, along with other autosomes. This raises the intriguing possibility of a translocation of the sex determination region within the Salicaceae lineage, suggesting a common evolutionary origin of the Populus and Salix sex determination loci.
Collapse
Affiliation(s)
- Ran Zhou
- Department of Biology, West Virginia University, 53 Campus Drive, Morgantown, WV, 26506-6057, USA
| | - David Macaya-Sanz
- Department of Biology, West Virginia University, 53 Campus Drive, Morgantown, WV, 26506-6057, USA
| | - Eli Rodgers-Melnick
- Department of Biology, West Virginia University, 53 Campus Drive, Morgantown, WV, 26506-6057, USA
| | - Craig H Carlson
- Horticulture Section, School of Integrative Plant Science, Cornell University, New York State Agricultural Experiment Station, Geneva, NY, 14456, USA
| | - Fred E Gouker
- Horticulture Section, School of Integrative Plant Science, Cornell University, New York State Agricultural Experiment Station, Geneva, NY, 14456, USA
| | - Luke M Evans
- Department of Biology, West Virginia University, 53 Campus Drive, Morgantown, WV, 26506-6057, USA
| | - Jeremy Schmutz
- HudsonAlpha Institute of Biotechnology, 601 Genome Way Northwest, Huntsville, AL, 35806, USA.,Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA, 94598, USA
| | - Jerry W Jenkins
- HudsonAlpha Institute of Biotechnology, 601 Genome Way Northwest, Huntsville, AL, 35806, USA
| | - Juying Yan
- Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA, 94598, USA
| | - Gerald A Tuskan
- Department of Energy Joint Genome Institute, 2800 Mitchell Drive, Walnut Creek, CA, 94598, USA.,Biosciences Division, Oak Ridge National Lab, Oak Ridge, USA
| | - Lawrence B Smart
- Horticulture Section, School of Integrative Plant Science, Cornell University, New York State Agricultural Experiment Station, Geneva, NY, 14456, USA
| | - Stephen P DiFazio
- Department of Biology, West Virginia University, 53 Campus Drive, Morgantown, WV, 26506-6057, USA.
| |
Collapse
|
20
|
Li S, Dong H, Pei W, Liu C, Zhang S, Sun T, Xue X, Ren H. LlFH1-mediated interaction between actin fringe and exocytic vesicles is involved in pollen tube tip growth. THE NEW PHYTOLOGIST 2017; 214:745-761. [PMID: 28092406 DOI: 10.1111/nph.14395] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 11/16/2016] [Indexed: 05/15/2023]
Abstract
Pollen tube tip growth is an extreme form of polarized cell growth, which requires polarized exocytosis based on a dynamic actin cytoskeleton. However, the molecular basis for the connection between actin filaments and exocytic vesicles is unclear. Here, we identified a Lilium longiflorum pollen-specific formin (LlFH1) and found that it localized at the apical vesicles and plasma membrane (PM). Overexpression of LlFH1 induced excessive actin cables in the tube tip region, and downregulation of LlFH1 eliminated the actin fringe. Fluorescence recovery after photobleaching (FRAP) analysis revealed that LlFH1-labeled exocytic vesicles exhibited an initial accumulation at the shoulder of the apex and coincided with the leading edge of the actin fringe. Time-lapse analysis suggested that nascent actin filaments followed the emergence of the apical vesicles, implying that LlFH1 at apical vesicles could initiate actin polymerization. Biochemical assays showed that LlFH1 FH1FH2 could nucleate actin polymerization, but then capped the actin filament at the barbed end and inhibited its elongation. However, in the presence of lily profilins, LlFH1 FH1FH2 could accelerate barbed-end actin elongation. In addition, LlFH1 FH1FH2 was able to bundle actin filaments. Thus, we propose that LlFH1 and profilin coordinate the interaction between the actin fringe and exocytic vesicle trafficking during pollen tube growth of lily.
Collapse
Affiliation(s)
- Shanwei Li
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education and College of Life Science, Beijing Normal University, Beijing, 100875, China
| | - Huaijian Dong
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education and College of Life Science, Beijing Normal University, Beijing, 100875, China
| | - Weike Pei
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education and College of Life Science, Beijing Normal University, Beijing, 100875, China
| | - Chaonan Liu
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education and College of Life Science, Beijing Normal University, Beijing, 100875, China
| | - Sha Zhang
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education and College of Life Science, Beijing Normal University, Beijing, 100875, China
| | - Tiantian Sun
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education and College of Life Science, Beijing Normal University, Beijing, 100875, China
| | - Xiuhua Xue
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education and College of Life Science, Beijing Normal University, Beijing, 100875, China
| | - Haiyun Ren
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education and College of Life Science, Beijing Normal University, Beijing, 100875, China
| |
Collapse
|
21
|
Zhong G, Liu R, Zhuang M, Wang H. Transient Expression of Chimeric Fluorescent Reporter Proteins in Pollen Tubes to Study Protein Polar Secretion and Dynamics. Methods Mol Biol 2017; 1662:115-124. [PMID: 28861822 DOI: 10.1007/978-1-4939-7262-3_10] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Transient expression of chimeric fluorescent reporter proteins by biolistic bombardment is a quick and useful procedure for studying subcellular protein localization and dynamics in plants. It is especially beneficial in specific plant cells which are not suitable for protoplast-based and Agrobacterium-mediated protein transient expression. Polar protein secretion and vesicular trafficking play essential functions for cell polarization and tip growth. The growing pollen tube is regarded as an ideal model plant cell system to study the machinery and regulation of polar protein trafficking and targeting. A large amount of newly synthesized proteins are packed and polarly transported to the apical region to support the rapid and highly polarized tip growth. Here, we described a detailed step-by-step protocol for the transient expression of chimeric fluorescent reporter proteins in growing Arabidopsis and tobacco pollen tubes to study polar transportation logistics and mechanisms. In addition, we have optimized the Arabidopsis and tobacco in vitro pollen germination medium and the conditions to maximize the efficiency of protein expression. As a proof of concept, we have used this protocol to express actin microfilament and late endosomal fluorescent markers in Arabidopsis and tobacco pollen tubes.
Collapse
Affiliation(s)
- Guitao Zhong
- College of Life Sciences, South China Agricultural University, 483 Wushan Road, Guangzhou, 510642, China
| | - Ronghe Liu
- College of Life Sciences, South China Agricultural University, 483 Wushan Road, Guangzhou, 510642, China
| | - Menglong Zhuang
- College of Life Sciences, South China Agricultural University, 483 Wushan Road, Guangzhou, 510642, China
| | - Hao Wang
- College of Life Sciences, South China Agricultural University, 483 Wushan Road, Guangzhou, 510642, China.
| |
Collapse
|
22
|
Wang H, Zhuang X, Wang X, Law AHY, Zhao T, Du S, Loy MMT, Jiang L. A Distinct Pathway for Polar Exocytosis in Plant Cell Wall Formation. PLANT PHYSIOLOGY 2016; 172:1003-1018. [PMID: 27531442 PMCID: PMC5047090 DOI: 10.1104/pp.16.00754] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 08/08/2016] [Indexed: 05/02/2023]
Abstract
Post-Golgi protein sorting and trafficking to the plasma membrane (PM) is generally believed to occur via the trans-Golgi network (TGN). In this study using Nicotiana tabacum pectin methylesterase (NtPPME1) as a marker, we have identified a TGN-independent polar exocytosis pathway that mediates cell wall formation during cell expansion and cytokinesis. Confocal immunofluorescence and immunogold electron microscopy studies demonstrated that Golgi-derived secretory vesicles (GDSVs) labeled by NtPPME1-GFP are distinct from those organelles belonging to the conventional post-Golgi exocytosis pathway. In addition, pharmaceutical treatments, superresolution imaging, and dynamic studies suggest that NtPPME1 follows a polar exocytic process from Golgi-GDSV-PM/cell plate (CP), which is distinct from the conventional Golgi-TGN-PM/CP secretion pathway. Further studies show that ROP1 regulates this specific polar exocytic pathway. Taken together, we have demonstrated an alternative TGN-independent Golgi-to-PM polar exocytic route, which mediates secretion of NtPPME1 for cell wall formation during cell expansion and cytokinesis and is ROP1-dependent.
Collapse
Affiliation(s)
- Hao Wang
- School of Life Sciences, Centre for Cell and Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China (H.W., X.Z., X.W., A.H.Y.L., L.J.);College of Life Sciences, South China Agricultural University, Guangzhou 510642, China (H.W.);Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China (T.Z., S.D., M.M.T.L.);Division of Biomedical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China (S.D.); andCUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen 518057, China (L.J.)
| | - Xiaohong Zhuang
- School of Life Sciences, Centre for Cell and Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China (H.W., X.Z., X.W., A.H.Y.L., L.J.);College of Life Sciences, South China Agricultural University, Guangzhou 510642, China (H.W.);Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China (T.Z., S.D., M.M.T.L.);Division of Biomedical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China (S.D.); andCUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen 518057, China (L.J.)
| | - Xiangfeng Wang
- School of Life Sciences, Centre for Cell and Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China (H.W., X.Z., X.W., A.H.Y.L., L.J.);College of Life Sciences, South China Agricultural University, Guangzhou 510642, China (H.W.);Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China (T.Z., S.D., M.M.T.L.);Division of Biomedical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China (S.D.); andCUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen 518057, China (L.J.)
| | - Angus Ho Yin Law
- School of Life Sciences, Centre for Cell and Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China (H.W., X.Z., X.W., A.H.Y.L., L.J.);College of Life Sciences, South China Agricultural University, Guangzhou 510642, China (H.W.);Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China (T.Z., S.D., M.M.T.L.);Division of Biomedical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China (S.D.); andCUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen 518057, China (L.J.)
| | - Teng Zhao
- School of Life Sciences, Centre for Cell and Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China (H.W., X.Z., X.W., A.H.Y.L., L.J.);College of Life Sciences, South China Agricultural University, Guangzhou 510642, China (H.W.);Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China (T.Z., S.D., M.M.T.L.);Division of Biomedical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China (S.D.); andCUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen 518057, China (L.J.)
| | - Shengwang Du
- School of Life Sciences, Centre for Cell and Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China (H.W., X.Z., X.W., A.H.Y.L., L.J.);College of Life Sciences, South China Agricultural University, Guangzhou 510642, China (H.W.);Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China (T.Z., S.D., M.M.T.L.);Division of Biomedical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China (S.D.); andCUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen 518057, China (L.J.)
| | - Michael M T Loy
- School of Life Sciences, Centre for Cell and Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China (H.W., X.Z., X.W., A.H.Y.L., L.J.);College of Life Sciences, South China Agricultural University, Guangzhou 510642, China (H.W.);Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China (T.Z., S.D., M.M.T.L.);Division of Biomedical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China (S.D.); andCUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen 518057, China (L.J.)
| | - Liwen Jiang
- School of Life Sciences, Centre for Cell and Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China (H.W., X.Z., X.W., A.H.Y.L., L.J.);College of Life Sciences, South China Agricultural University, Guangzhou 510642, China (H.W.);Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China (T.Z., S.D., M.M.T.L.);Division of Biomedical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China (S.D.); andCUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen 518057, China (L.J.)
| |
Collapse
|
23
|
Aloisi I, Cai G, Tumiatti V, Minarini A, Del Duca S. Natural polyamines and synthetic analogs modify the growth and the morphology of Pyrus communis pollen tubes affecting ROS levels and causing cell death. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2015; 239:92-105. [PMID: 26398794 DOI: 10.1016/j.plantsci.2015.07.008] [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: 04/21/2015] [Revised: 06/05/2015] [Accepted: 07/10/2015] [Indexed: 06/05/2023]
Abstract
Polyamines (PAs) are small molecules necessary for pollen maturation and tube growth. Their role is often controversial, since they may act as pro-survival factors as well as factors promoting Programmed Cell Death (PCD). The aim of the present work was to evaluate the effect of exogenous PAs on the apical growth of pear (Pyrus communis) pollen tube and to understand if PAs and reactive oxygen species (ROS) are interconnected in the process of tip-growth. In the present study besides natural PAs, also aryl-substituted spermine and methoctramine (Met 6-8-6) analogs were tested. Among the natural PAs, Spm showed strongest effects on tube growth. Spm entered through the pollen tube tip, then diffused in the sub-apical region that underwent drastic morphological changes, showing enlarged tip. Analogs were mostly less efficient than natural PAs but BD23, an asymmetric synthetic PAs bearing a pyridine ring, showed similar effects. These effects were related to the ability of PAs to cause the decrease of ROS level in the apical zone, leading to cell death, counteracted by the caspase-3 inhibitor Ac-DEVD-CHO (DEVD). In conclusions, ROS are essential for pollen germination and a strict correlation between ROS regulation and PA concentration is reported. Moreover, an imbalance between ROS and PAs can be detrimental thereby driving pollen toward cell death.
Collapse
Affiliation(s)
- Iris Aloisi
- Dipartimento di Scienze Biologiche, Geologiche e Ambientali, Alma Mater Studiorum-Università di Bologna, Via Irnerio 42, Bologna, Italy
| | - Giampiero Cai
- Dipartimento di Scienze della Vita, Università di Siena, Via Mattioli 4, Siena, Italy
| | - Vincenzo Tumiatti
- Dipartimento di Scienze per la Qualità della Vita, Alma Mater Studiorum-Università di Bologna, Corso d'Augusto 25, Rimini, Italy
| | - Anna Minarini
- Dipartimento di Farmacia e Biotecnologie, Alma Mater Studiorum-Università di Bologna, Via Belmeloro 6, Bologna, Italy
| | - Stefano Del Duca
- Dipartimento di Scienze Biologiche, Geologiche e Ambientali, Alma Mater Studiorum-Università di Bologna, Via Irnerio 42, Bologna, Italy.
| |
Collapse
|
24
|
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.
Collapse
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
| |
Collapse
|
25
|
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.
Collapse
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.
| |
Collapse
|
26
|
Hepler PK, Winship LJ. The pollen tube clear zone: clues to the mechanism of polarized growth. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2015; 57:79-92. [PMID: 25431342 DOI: 10.1111/jipb.12315] [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: 07/29/2014] [Accepted: 11/24/2014] [Indexed: 05/08/2023]
Abstract
Pollen tubes usually exhibit a prominent region at their apex called the "clear zone" because it lacks light refracting amyloplasts. A robust, long clear zone often associates with fast growing pollen tubes, and thus serves as an indicator of pollen tube health. Nevertheless we do not understand how it arises or how it is maintained. Here we review the structure of the clear zone, and attempt to explain the factors that contribute to its formation. While amyloplasts and vacuolar elements are excluded from the clear zone, virtually all other organelles are present including secretory vesicles, mitochondria, Golgi dictyosomes, and the endoplasmic reticulum (ER). Secretory vesicles aggregate into an inverted cone appressed against the apical plasma membrane. ER elements move nearly to the extreme apex, whereas mitochondria and Golgi dictyosomes move less far forward. The cortical actin fringe assumes a central position in the control of clear zone formation and maintenance, given its role in generating cytoplasmic streaming. Other likely factors include the tip-focused calcium gradient, the apical pH gradient, the influx of water, and a host of signaling factors (small G-proteins). We think that the clear zone is an emergent property that depends on the interaction of several factors crucial for polarized growth.
Collapse
Affiliation(s)
- Peter K Hepler
- Biology Department, University of Massachusetts, Amherst, Massachusetts, 01003, USA
| | | |
Collapse
|
27
|
Akita K, Higaki T, Kutsuna N, Hasezawa S. Quantitative analysis of microtubule orientation in interdigitated leaf pavement cells. PLANT SIGNALING & BEHAVIOR 2015; 10:e1024396. [PMID: 26039484 PMCID: PMC4622981 DOI: 10.1080/15592324.2015.1024396] [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] [Indexed: 05/02/2023]
Abstract
Leaf pavement cells are shaped like a jigsaw puzzle in most dicotyledon species. Molecular genetic studies have identified several genes required for pavement cells morphogenesis and proposed that microtubules play crucial roles in the interdigitation of pavement cells. In this study, we performed quantitative analysis of cortical microtubule orientation in leaf pavement cells in Arabidopsis thaliana. We captured confocal images of cortical microtubules in cotyledon leaf epidermis expressing GFP-tubulinβ and quantitatively evaluated the microtubule orientations relative to the pavement cell growth axis using original image processing techniques. Our results showed that microtubules kept parallel orientations to the growth axis during pavement cell growth. In addition, we showed that immersion treatment of seed cotyledons in solutions containing tubulin polymerization and depolymerization inhibitors decreased pavement cell complexity. Treatment with oryzalin and colchicine inhibited the symmetric division of guard mother cells.
Collapse
Affiliation(s)
- Kae Akita
- Department of Integrated Biosciences; Graduate School of Frontier Sciences; The University of Tokyo; Kashiwanoha; Kashiwa, Chiba, Japan
- Correspondence to: K. Akita;
| | - Takumi Higaki
- Department of Integrated Biosciences; Graduate School of Frontier Sciences; The University of Tokyo; Kashiwanoha; Kashiwa, Chiba, Japan
| | - Natsumaro Kutsuna
- Department of Integrated Biosciences; Graduate School of Frontier Sciences; The University of Tokyo; Kashiwanoha; Kashiwa, Chiba, Japan
- Research and Development Division; LPixel Inc.; Bunkyo-ku, Tokyo, Japan
| | - Seiichiro Hasezawa
- Department of Integrated Biosciences; Graduate School of Frontier Sciences; The University of Tokyo; Kashiwanoha; Kashiwa, Chiba, Japan
| |
Collapse
|
28
|
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.
Collapse
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
| |
Collapse
|
29
|
Vildanova MS, Wang W, Smirnova EA. Specific organization of Golgi apparatus in plant cells. BIOCHEMISTRY (MOSCOW) 2014; 79:894-906. [DOI: 10.1134/s0006297914090065] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
30
|
Zhu J, Wu X, Yuan S, Qian D, Nan Q, An L, Xiang Y. Annexin5 plays a vital role in Arabidopsis pollen development via Ca2+-dependent membrane trafficking. PLoS One 2014; 9:e102407. [PMID: 25019283 PMCID: PMC4097066 DOI: 10.1371/journal.pone.0102407] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2014] [Accepted: 06/18/2014] [Indexed: 12/22/2022] Open
Abstract
The regulation of pollen development and pollen tube growth is a complicated biological process that is crucial for sexual reproduction in flowering plants. Annexins are widely distributed from protists to higher eukaryotes and play multiple roles in numerous cellular events by acting as a putative "linker" between Ca2+ signaling, the actin cytoskeleton and the membrane, which are required for pollen development and pollen tube growth. Our recent report suggested that downregulation of the function of Arabidopsis annexin 5 (Ann5) in transgenic Ann5-RNAi lines caused severely sterile pollen grains. However, little is known about the underlying mechanisms of the function of Ann5 in pollen. This study demonstrated that Ann5 associates with phospholipid membrane and this association is stimulated by Ca2+ in vitro. Brefeldin A (BFA) interferes with endomembrane trafficking and inhibits pollen germination and pollen tube growth. Both pollen germination and pollen tube growth of Ann5-overexpressing plants showed increased resistance to BFA treatment, and this effect was regulated by calcium. Overexpression of Ann5 promoted Ca2+-dependent cytoplasmic streaming in pollen tubes in vivo in response to BFA. Lactrunculin (LatB) significantly prohibited pollen germination and tube growth by binding with high affinity to monomeric actin and preferentially targeting dynamic actin filament arrays and preventing actin polymerization. Overexpression of Ann5 did not affect pollen germination or pollen tube growth in response to LatB compared with wild-type, although Ann5 interacts with actin filaments in a manner similar to some animal annexins. In addition, the sterile pollen phenotype could be only partially rescued by Ann5 mutants at Ca2+-binding sites when compared to the complete recovery by wild-type Ann5. These data demonstrated that Ann5 is involved in pollen development, germination and pollen tube growth through the promotion of endomembrane trafficking modulated by calcium. Our results provide reliable molecular mechanisms that underlie the function of Ann5 in pollen.
Collapse
Affiliation(s)
- Jingen Zhu
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Xiaorong Wu
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Shunjie Yuan
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Dong Qian
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Qiong Nan
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Lizhe An
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Yun Xiang
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, China
| |
Collapse
|
31
|
No stress! Relax! Mechanisms governing growth and shape in plant cells. Int J Mol Sci 2014; 15:5094-114. [PMID: 24663059 PMCID: PMC3975442 DOI: 10.3390/ijms15035094] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Revised: 03/03/2014] [Accepted: 03/04/2014] [Indexed: 12/15/2022] Open
Abstract
The mechanisms through which plant cells control growth and shape are the result of the coordinated action of many events, notably cell wall stress relaxation and turgor-driven expansion. The scalar nature of turgor pressure would drive plant cells to assume spherical shapes; however, this is not the case, as plant cells show an amazing variety of morphologies. Plant cell walls are dynamic structures that can display alterations in matrix polysaccharide composition and concentration, which ultimately affect the wall deformation rate. The wide varieties of plant cell shapes, spanning from elongated cylinders (as pollen tubes) and jigsaw puzzle-like epidermal cells, to very long fibres and branched stellate leaf trichomes, can be understood if the underlying mechanisms regulating wall biosynthesis and cytoskeletal dynamics are addressed. This review aims at gathering the available knowledge on the fundamental mechanisms regulating expansion, growth and shape in plant cells by putting a special emphasis on the cell wall-cytoskeleton system continuum. In particular, we discuss from a molecular point of view the growth mechanisms characterizing cell types with strikingly different geometries and describe their relationship with primary walls. The purpose, here, is to provide the reader with a comprehensive overview of the multitude of events through which plant cells manage to expand and control their final shapes.
Collapse
|
32
|
Szechyńska-Hebda M, Karpiński S. Light intensity-dependent retrograde signalling in higher plants. JOURNAL OF PLANT PHYSIOLOGY 2013; 170:1501-16. [PMID: 23850030 DOI: 10.1016/j.jplph.2013.06.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Revised: 06/07/2013] [Accepted: 06/10/2013] [Indexed: 05/23/2023]
Abstract
Plants are able to acclimate to highly fluctuating light environment and evolved a short- and long-term light acclimatory responses, that are dependent on chloroplasts retrograde signalling. In this review we summarise recent evidences suggesting that the chloroplasts act as key sensors of light intensity changes in a wide range (low, high and excess light conditions) as well as sensors of darkness. They also participate in transduction and synchronisation of systemic retrograde signalling in response to differential light exposure of distinct leaves. Regulation of intra- and inter-cellular chloroplast retrograde signalling is dependent on the developmental and functional stage of the plastids. Therefore, it is discussed in following subsections: firstly, chloroplast biogenic control of nuclear genes, for example, signals related to photosystems and pigment biogenesis during early plastid development; secondly, signals in the mature chloroplast induced by changes in photosynthetic electron transport, reactive oxygen species, hormones and metabolite biosynthesis; thirdly, chloroplast signalling during leaf senescence. Moreover, with a help of meta-analysis of multiple microarray experiments, we showed that the expression of the same set of genes is regulated specifically in particular types of signals and types of light conditions. Furthermore, we also highlight the alternative scenarios of the chloroplast retrograde signals transduction and coordination linked to the role of photo-electrochemical signalling.
Collapse
Affiliation(s)
- Magdalena Szechyńska-Hebda
- Institute of Plant Physiology, Polish Academy of Sciences, 30-239 Kraków, Poland; Department of Plant Genetics, Breeding and Biotechnology, Faculty of Horticulture, Biotechnology and Landscape Architecture, Warsaw University of Life Sciences, 02-776 Warszawa, Poland
| | | |
Collapse
|
33
|
Wang H, Zhuang X, Cai Y, Cheung AY, Jiang L. Apical F-actin-regulated exocytic targeting of NtPPME1 is essential for construction and rigidity of the pollen tube cell wall. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2013; 76:367-79. [PMID: 23906068 DOI: 10.1111/tpj.12300] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Revised: 07/15/2013] [Accepted: 07/18/2013] [Indexed: 05/03/2023]
Abstract
In tip-confined growing pollen tubes, delivery of newly synthesized cell wall materials to the rapidly expanding apical surface requires spatial organization and temporal regulation of the apical F-actin filament and exocytosis. In this study, we demonstrate that apical F-actin is essential for the rigidity and construction of the pollen tube cell wall by regulating exocytosis of Nicotiana tabacum pectin methylesterase (NtPPME1). Wortmannin disrupts the spatial organization of apical F-actin in the pollen tube tip and inhibits polar targeting of NtPPME1, which subsequently alters the rigidity and pectic composition of the pollen tube cell wall, finally causing growth arrest of the pollen tube. In addition to mechanistically linking cell wall construction and apical F-actin, wortmannin can be used as a useful tool for studying endomembrane trafficking and cytoskeletal organization in pollen tubes.
Collapse
Affiliation(s)
- Hao Wang
- School of Life Sciences, Centre for Cell and Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | | | | | | | | |
Collapse
|
34
|
Parrotta L, Cresti M, Cai G. Heat-shock protein 70 binds microtubules and interacts with kinesin in tobacco pollen tubes. Cytoskeleton (Hoboken) 2013; 70:522-37. [PMID: 24039249 DOI: 10.1002/cm.21134] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2013] [Revised: 08/15/2013] [Accepted: 08/21/2013] [Indexed: 11/11/2022]
Abstract
The heat-shock proteins of 70 kDa are a family of ubiquitously expressed proteins important for protein folding. Heat-shock protein 70 assists other nascent proteins to achieve the spatial structure and ultimately helps the cell to protect against stress factors, such as heat. These proteins are localized in different cellular compartments and are associated with the cytoskeleton. We identified a heat-shock protein 70 isoform in the pollen tube of tobacco that binds to microtubules in an ATP-dependent manner. The heat-shock protein 70 was identified as part of the so-called ATP-MAP (ATP-dependent microtubule-associated protein) fraction, which also includes the 90-kDa kinesin, a mitochondria-associated motor protein. The identity of heat-shock protein 70 was validated by immunological assays and mass spectrometry. Sequence analysis showed that this heat-shock protein 70 is more similar to specific heat-shock proteins of Arabidopsis than to corresponding proteins of tobacco. Two-dimensional electrophoresis indicated that this heat-shock protein 70 isoform only is part of the ATP-MAP fraction and that is associated with the mitochondria of pollen tubes. Sedimentation assays showed that the binding of heat-shock protein 70 to microtubules is not affected by AMPPNP but it increases in the presence of the 90-kDa kinesin. Binding of heat-shock protein 70 to microtubules occurs only partially in the presence of ATP but it does not occur if, in addition to ATP, the 90-kDa kinesin is also present. Data suggest that the binding (but not the release) of heat-shock protein 70 to microtubules is facilitated by the 90-kDa kinesin.
Collapse
Affiliation(s)
- Luigi Parrotta
- Dipartimento di Scienze della Vita, Università di Siena, via Mattioli 4, 53100, Siena, Italy
| | | | | |
Collapse
|
35
|
Hepler PK, Rounds CM, Winship LJ. Control of cell wall extensibility during pollen tube growth. MOLECULAR PLANT 2013; 6:998-1017. [PMID: 23770837 PMCID: PMC4043104 DOI: 10.1093/mp/sst103] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
In this review, we address the question of how the tip-growing pollen tube achieves its rapid rate of elongation while maintaining an intact cell wall. Although turgor is essential for growth to occur, the local expansion rate is controlled by local changes in the viscosity of the apical wall. We focus on several different structures and underlying processes that are thought to be major participants including exocytosis, the organization and activity of the actin cytoskeleton, calcium and proton physiology, and cellular energetics. We think that the actin cytoskeleton, in particular the apical cortical actin fringe, directs the flow of vesicles to the apical domain, where they fuse with the plasma membrane and contribute their contents to the expanding cell wall. While pH gradients, as generated by a proton-ATPase located on the plasma membrane along the side of the clear zone, may regulate rapid actin turnover and new polymerization in the fringe, the tip-focused calcium gradient biases secretion towards the polar axis. The recent data showing that exocytosis of new wall material precedes and predicts the process of cell elongation provide support for the idea that the intussusception of newly secreted pectin contributes to decreases in apical wall viscosity and to cell expansion. Other prime factors will be the localization and activity of the enzyme pectin methyl-esterase, and the chelation of calcium by pectic acids. Finally, we acknowledge a role for reactive oxygen species in the control of wall viscosity.
Collapse
Affiliation(s)
- Peter K Hepler
- Biology Department, University of Massachusetts, Amherst, MA 01003, USA.
| | | | | |
Collapse
|
36
|
Abstract
Cellular organelles move within the cellular volume and the effect of the resulting drag forces on the liquid causes bulk movement in the cytosol. The movement of both organelles and cytosol leads to an overall motion pattern called cytoplasmic streaming or cyclosis. This streaming enables the active and passive transport of molecules and organelles between cellular compartments. Furthermore, the fusion and budding of vesicles with and from the plasma membrane (exo/endocytosis) allow for transport of material between the inside and the outside of the cell. In the pollen tube, cytoplasmic streaming and exo/endocytosis are very active and fulfill several different functions. In this review, we focus on the logistics of intracellular motion and transport processes as well as their biophysical underpinnings. We discuss various modeling attempts that have been performed to understand both long-distance shuttling and short-distance targeting of organelles. We show how the combination of mechanical and mathematical modeling with cell biological approaches has contributed to our understanding of intracellular transport logistics.
Collapse
Affiliation(s)
- Youssef Chebli
- Département de Sciences Biologiques, Institut de Recherche en Biologie Végétale, Université de Montréal, Montréal, Québec, Canada
| | | | | |
Collapse
|
37
|
Cai G, Serafini-Fracassini D, Del Duca S. Regulation of Pollen Tube Growth by Transglutaminase. PLANTS 2013; 2:87-106. [PMID: 27137368 PMCID: PMC4844290 DOI: 10.3390/plants2010087] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/05/2013] [Revised: 02/08/2013] [Accepted: 02/27/2013] [Indexed: 11/23/2022]
Abstract
In pollen tubes, cytoskeleton proteins are involved in many aspects of pollen germination and growth, from the transport of sperm cells to the asymmetrical distribution of organelles to the deposition of cell wall material. These activities are based on the dynamics of the cytoskeleton. Changes to both actin filaments and microtubules are triggered by specific proteins, resulting in different organization levels suitable for the different functions of the cytoskeleton. Transglutaminases are enzymes ubiquitous in all plant organs and cell compartments. They catalyze the post-translational conjugation of polyamines to different protein targets, such as the cytoskeleton. Transglutaminases are suggested to have a general role in the interaction between pollen tubes and the extracellular matrix during fertilization and a specific role during the self-incompatibility response. In such processes, the activity of transglutaminases is enhanced, leading to the formation of cross-linked products (including aggregates of tubulin and actin). Consequently, transglutaminases are suggested to act as regulators of cytoskeleton dynamics. The distribution of transglutaminases in pollen tubes is affected by both membrane dynamics and the cytoskeleton. Transglutaminases are also secreted in the extracellular matrix, where they may take part in the assembly and/or strengthening of the pollen tube cell wall.
Collapse
Affiliation(s)
- Giampiero Cai
- Dipartimento di Scienze della Vita, Università degli Studi di Siena, via Mattioli 4, Siena 53100, Italy.
| | - Donatella Serafini-Fracassini
- Dipartimento di Scienze Biologiche, Geologiche e Ambientali, Università degli Studi di Bologna, via Irnerio, Bologna 40126, Italy.
| | - Stefano Del Duca
- Dipartimento di Scienze Biologiche, Geologiche e Ambientali, Università degli Studi di Bologna, via Irnerio, Bologna 40126, Italy.
| |
Collapse
|
38
|
Zhu L, Zhang Y, Kang E, Xu Q, Wang M, Rui Y, Liu B, Yuan M, Fu Y. MAP18 regulates the direction of pollen tube growth in Arabidopsis by modulating F-actin organization. THE PLANT CELL 2013; 25:851-67. [PMID: 23463774 PMCID: PMC3634693 DOI: 10.1105/tpc.113.110528] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
For fertilization to occur in plants, the pollen tube must be guided to enter the ovule via the micropyle. Previous reports have implicated actin filaments, actin binding proteins, and the tip-focused calcium gradient as key contributors to polar growth of pollen tubes; however, the regulation of directional pollen tube growth is largely unknown. We reported previously that Arabidopsis thaliana MICROTUBULE-ASSOCIATED PROTEIN18 (MAP18) contributes to directional cell growth and cortical microtubule organization. The preferential expression of MAP18 in pollen and in pollen tubes suggests that MAP18 also may function in pollen tube growth. In this study, we demonstrate that MAP18 functions in pollen tubes by influencing actin organization, rather than microtubule assembly. In vitro biochemical results indicate that MAP18 exhibits Ca(2+)-dependent filamentous (F)-actin-severing activity. Abnormal expression of MAP18 in map18 and MAP18 OX plants was associated with disorganization of the actin cytoskeleton in the tube apex, resulting in aberrant pollen tube growth patterns and morphologies, inaccurate micropyle targeting, and fewer fertilization events. Experiments with MAP18 mutants created by site-directed mutagenesis suggest that F-actin-severing activity is essential to the effects of MAP18 on pollen tube growth direction. Our study demonstrates that in Arabidopsis, MAP18 guides the direction of pollen tube growth by modulating actin filaments.
Collapse
|
39
|
Furt F, Liu YC, Bibeau JP, Tüzel E, Vidali L. Apical myosin XI anticipates F-actin during polarized growth of Physcomitrella patens cells. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2013; 73:417-428. [PMID: 23020796 DOI: 10.1111/tpj.12039] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Revised: 09/07/2012] [Accepted: 09/27/2012] [Indexed: 05/28/2023]
Abstract
Tip growth is essential for land colonization by bryophytes, plant sexual reproduction and water and nutrient uptake. Because this specialized form of polarized cell growth requires both a dynamic actin cytoskeleton and active secretion, it has been proposed that the F-actin-associated motor myosin XI is essential for this process. Nevertheless, a spatial and temporal relationship between myosin XI and F-actin during tip growth is not known in any plant cell. Here, we use the highly polarized cells of the moss Physcomitrella patens to show that myosin XI and F-actin localize, in vivo, at the same apical domain and that both signals fluctuate. Surprisingly, phase analysis shows that increase in myosin XI anticipates that of F-actin; in contrast, myosin XI levels at the tip fluctuate in identical phase with a vesicle marker. Pharmacological analysis using a low concentration of the actin polymerization inhibitor latrunculin B showed that the F-actin at the tip can be significantly diminished while myosin XI remains elevated in this region, suggesting that a mechanism exists to cluster myosin XI-associated structures at the cell's apex. In addition, this approach uncovered a mechanism for actin polymerization-dependent motility in the moss cytoplasm, where myosin XI-associated structures seem to anticipate and organize the actin polymerization machinery. From our results, we inferred a model where the interaction between myosin XI-associated vesicular structures and F-actin polymerization-driven motility function at the cell's apex to maintain polarized cell growth. We hypothesize this is a general mechanism for the participation of myosin XI and F-actin in tip growing cells.
Collapse
Affiliation(s)
- Fabienne Furt
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA 01609, USA
| | | | | | | | | |
Collapse
|
40
|
Kroeger J, Geitmann A. The pollen tube paradigm revisited. CURRENT OPINION IN PLANT BIOLOGY 2012; 15:618-24. [PMID: 23000432 DOI: 10.1016/j.pbi.2012.09.007] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Revised: 08/31/2012] [Accepted: 09/03/2012] [Indexed: 05/10/2023]
Abstract
The polar growth process characterizing pollen tube elongation has attracted numerous modeling attempts over the past years. While initial models focused on recreating the correct cellular geometry, recent models are increasingly based on experimentally assessed cellular parameters such as the dynamics of signaling processes and the mechanical properties of the cell wall. Recent modeling attempts have therefore substantially gained in biological relevance and predictive power. Different modeling methods are explained and the power and limitations of individual models are compared. Focus is on several recent models that use closed feedback loops in order to generate limit cycles representing the oscillatory behavior observed in growing tubes.
Collapse
|
41
|
Steinhorst L, Kudla J. Calcium - a central regulator of pollen germination and tube growth. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2012; 1833:1573-81. [PMID: 23072967 DOI: 10.1016/j.bbamcr.2012.10.009] [Citation(s) in RCA: 193] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Revised: 10/01/2012] [Accepted: 10/06/2012] [Indexed: 12/30/2022]
Abstract
Pollen tubes grow rapidly by very fast rates and reach extended lengths to bring about fertilization during plant reproduction. The pollen tube grows exclusively at its tip. Fundamental for such local, tip-focused growth are the presence of internal gradients and transmembrane fluxes of ions. Consequently, vegetative pollen tube cells are an excellent single cell model system to investigate cell biological processes of vesicle transport, cytoskeleton reorganization and regulation of ion transport. The second messenger Ca(2+) has emerged as a central and crucial modulator that not only regulates but also integrates the coordination each of these processes. In this review we reflect on recent advances in our understanding of the mechanisms of Ca(2+) function in pollen tube growth, focusing on its role in basic cellular processes such as control of cell growth, vesicular transport and intracellular signaling by localized gradients of second messengers. In particular we discuss new insights into the identity and role of Ca(2+) conductive ion channels and present experimental addressable hypotheses about their regulation. This article is part of a Special Issue entitled:12th European Symposium on Calcium.
Collapse
Affiliation(s)
- Leonie Steinhorst
- Institut für Biologie und Biotechnologie der Pflanzen, Universität Münster, Münster, Germany
| | | |
Collapse
|
42
|
Roldán JA, Rojas HJ, Goldraij A. Disorganization of F-actin cytoskeleton precedes vacuolar disruption in pollen tubes during the in vivo self-incompatibility response in Nicotiana alata. ANNALS OF BOTANY 2012; 110:787-95. [PMID: 22782242 PMCID: PMC3423811 DOI: 10.1093/aob/mcs153] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2011] [Accepted: 05/03/2012] [Indexed: 05/23/2023]
Abstract
BACKGROUND AND AIMS The integrity of actin filaments (F-actin) is essential for pollen-tube growth. In S-RNase-based self-incompatibility (SI), incompatible pollen tubes are inhibited in the style. Consequently, research efforts have focused on the alterations of pollen F-actin cytoskeleton during the SI response. However, so far, these studies were carried out in in vitro-grown pollen tubes. This study aimed to assess the timing of in vivo changes of pollen F-actin cytoskeleton taking place after compatible and incompatible pollinations in Nicotiana alata. To our knowledge, this is the first report of the in vivo F-actin alterations occurring during pollen rejection in the S-RNase-based SI system. METHODS The F-actin cytoskeleton and the vacuolar endomembrane system were fluorescently labelled in compatibly and incompatibly pollinated pistils at different times after pollination. The alterations induced by the SI reaction in pollen tubes were visualized by confocal laser scanning microscopy. KEY RESULTS Early after pollination, about 70 % of both compatible and incompatible pollen tubes showed an organized pattern of F-actin cables along the main axis of the cell. While in compatible pollinations this percentage was unchanged until pollen tubes reached the ovary, pollen tubes of incompatible pollinations underwent gradual and progressive F-actin disorganization. Colocalization of the F-actin cytoskeleton and the vacuolar endomembrane system, where S-RNases are compartmentalized, revealed that by day 6 after incompatible pollination, when the pollen-tube growth was already arrested, about 80 % of pollen tubes showed disrupted F-actin but a similar percentage had intact vacuolar compartments. CONCLUSIONS The results indicate that during the SI response in Nicotiana, disruption of the F-actin cytoskeleton precedes vacuolar membrane breakdown. Thus, incompatible pollen tubes undergo a sequential disorganization process of major subcellular structures. Results also suggest that the large pool of S-RNases released from vacuoles acts late in pollen rejection, after significant subcellular changes in incompatible pollen tubes.
Collapse
Affiliation(s)
| | | | - Ariel Goldraij
- Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC–CONICET), Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, X5000HUA, Córdoba, Argentina
| |
Collapse
|
43
|
Idilli AI, Onelli E, Moscatelli A. Low concentration of LatB dramatically changes the microtubule organization and the timing of vegetative nucleus/generative cell entrance in tobacco pollen tubes. PLANT SIGNALING & BEHAVIOR 2012; 7:947-50. [PMID: 22827942 PMCID: PMC3474692 DOI: 10.4161/psb.20907] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Low concentration of LatB inhibits not only the actin polymerization, but also induces profound alteration of MT distribution in pollen tubes of Nicotiana tabacum. The short randomly oriented MTs in the apical and subapical regions, became organized as bundles forming subapical rings or basket-like structures, surrounding the apex. Moreover, the depolymerization of AFs in the cortical regions of the apex and subapical region affects the timing of entrance of the vegetative nucleus and generative cell into the pollen tube.
Collapse
|
44
|
Furt F, Lemoi K, Tüzel E, Vidali L. Quantitative analysis of organelle distribution and dynamics in Physcomitrella patens protonemal cells. BMC PLANT BIOLOGY 2012; 12:70. [PMID: 22594499 PMCID: PMC3476433 DOI: 10.1186/1471-2229-12-70] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Accepted: 05/17/2012] [Indexed: 05/19/2023]
Abstract
BACKGROUND In the last decade, the moss Physcomitrella patens has emerged as a powerful plant model system, amenable for genetic manipulations not possible in any other plant. This moss is particularly well suited for plant polarized cell growth studies, as in its protonemal phase, expansion is restricted to the tip of its cells. Based on pollen tube and root hair studies, it is well known that tip growth requires active secretion and high polarization of the cellular components. However, such information is still missing in Physcomitrella patens. To gain insight into the mechanisms underlying the participation of organelle organization in tip growth, it is essential to determine the distribution and the dynamics of the organelles in moss cells. RESULTS We used fluorescent protein fusions to visualize and track Golgi dictyosomes, mitochondria, and peroxisomes in live protonemal cells. We also visualized and tracked chloroplasts based on chlorophyll auto-fluorescence. We showed that in protonemata all four organelles are distributed in a gradient from the tip of the apical cell to the base of the sub-apical cell. For example, the density of Golgi dictyosomes is 4.7 and 3.4 times higher at the tip than at the base in caulonemata and chloronemata respectively. While Golgi stacks are concentrated at the extreme tip of the caulonemata, chloroplasts and peroxisomes are totally excluded. Interestingly, caulonemata, which grow faster than chloronemata, also contain significantly more Golgi dictyosomes and fewer chloroplasts than chloronemata. Moreover, the motility analysis revealed that organelles in protonemata move with low persistency and average instantaneous speeds ranging from 29 to 75 nm/s, which are at least three orders of magnitude slower than those of pollen tube or root hair organelles. CONCLUSIONS To our knowledge, this study reports the first quantitative analysis of organelles in Physcomitrella patens and will make possible comparisons of the distribution and dynamics of organelles from different tip growing plant cells, thus enhancing our understanding of the mechanisms of plant polarized cell growth.
Collapse
Affiliation(s)
- Fabienne Furt
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA, 01609, USA
| | - Kyle Lemoi
- Department of Physics, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA, 01609, USA
| | - Erkan Tüzel
- Department of Physics, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA, 01609, USA
| | - Luis Vidali
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA, 01609, USA
| |
Collapse
|
45
|
Konrad KR, Wudick MM, Feijó JA. Calcium regulation of tip growth: new genes for old mechanisms. CURRENT OPINION IN PLANT BIOLOGY 2011; 14:721-30. [PMID: 22000040 DOI: 10.1016/j.pbi.2011.09.005] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Revised: 09/19/2011] [Accepted: 09/20/2011] [Indexed: 05/08/2023]
Abstract
We review the recent advances on Ca(2+) in tip-growing cells, with a special focus on pollen tubes. New genes for Ca(2+) pumps, channels and sensing proteins have been recently described, with special emphasis on cyclic nucleotide gated channels (CNGCs) and glutamate receptor-like channels (GLRs). We also review the current state of knowledge in what concerns Ca(2+) sensor and relay proteins, where the knowledge of the cell models is less advanced. While these newly described genes offer promise to a better understanding of the spatial and temporal patterns of Ca(2+) signalling that may be relevant for the formation of the phenotype, we discuss the necessity to investigate further links in the network downstream of the Ca(2+) signature, with a special need for mechanisms of feed-back that might render functional feed-back loops approachable by modelling and genetics. Given the available literature, we conclude on the need to investigate more on the role of two specific classes of proteins, the calcium binding protein kinases (CPKs) and the Calcineurin B-like proteins (CBLs) and their regulatory relationships to ion channels (summarized in Figure 3b).
Collapse
Affiliation(s)
- Kai R Konrad
- Instituto Gulbenkian de Ciência, P-2780-156 Oeiras, Portugal
| | | | | |
Collapse
|
46
|
Poulter NS, Bosch M, Franklin-Tong VE. Proteins implicated in mediating self-incompatibility-induced alterations to the actin cytoskeleton of Papaver pollen. ANNALS OF BOTANY 2011; 108:659-75. [PMID: 21320881 PMCID: PMC3170148 DOI: 10.1093/aob/mcr022] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2010] [Accepted: 01/04/2011] [Indexed: 05/20/2023]
Abstract
BACKGROUND AND AIMS Sexual reproduction in angiosperms involves a network of signalling and interactions between pollen and pistil. To promote out-breeding, an additional layer of interactions, involving self-incompatibility (SI), is used to prevent self-fertilization. SI is generally controlled by the S-locus, and comprises allelic pollen and pistil S-determinants. This provides the basis of recognition, and consequent rejection, of incompatible pollen. In Papaver rhoeas, SI involves interaction of pistil PrsS and pollen PrpS, triggering a Ca(2+)-dependent signalling network. This results in rapid and distinctive alterations to both the actin and microtubule cytoskeleton being triggered in 'self' pollen. Some of these alterations are implicated in mediating programmed cell death, involving activation of several caspase-like proteases. SCOPE Here we review and discuss our current understanding of the cytoskeletal alterations induced in incompatible pollen during SI and their relationship with programmed cell death. We focus on data relating to the formation of F-actin punctate foci, which have, to date, not been well characterized. The identification of two actin-binding proteins that interact with these structures are reviewed. Using an approach that enriched for F-actin from SI-induced pollen tubes using affinity purification followed by mass spectrometry, further proteins were identified as putative interactors with the F-actin foci in an SI situation. KEY RESULTS Previously two important actin-binding proteins, CAP and ADF, had been identified whose localization altered with SI, both showing co-localization with the F-actin punctate foci based on immunolocalization studies. Further analysis has identified differences between proteins associated with F-actin from SI-induced pollen samples and those associated with F-actin in untreated pollen. This provides candidate proteins implicated in either the formation or stabilization of the punctate actin structures formed during SI. CONCLUSIONS This review brings together for the first time, our current understanding of proteins and events involved in SI-induced signalling to the actin cytoskeleton in incompatible Papaver pollen.
Collapse
|
47
|
Wang H, Zhuang XH, Hillmer S, Robinson DG, Jiang LW. Vacuolar sorting receptor (VSR) proteins reach the plasma membrane in germinating pollen tubes. MOLECULAR PLANT 2011; 4:845-53. [PMID: 21430175 DOI: 10.1093/mp/ssr011] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Vacuolar sorting receptors (VSRs) are type I integral membrane proteins that mediate the vacuolar transport of soluble cargo proteins via prevacuolar compartments (PVCs) in plants. Confocal immunofluorescent and immunogold Electron Microscope (EM) studies have localized VSRs to PVCs or multivesicular bodies (MVBs) and trans-Golgi network (TGN) in various plant cell types, including suspension culture cells, root cells, developing and germinating seeds. Here, we provide evidence that VSRs reach plasma membrane (PM) in growing pollen tubes. Both immunofluorescent and immunogold EM studies with specific VSR antibodies show that, in addition to the previously demonstrated PVC/MVB localization, VSRs also localize to PM in lily and tobacco pollen tubes prepared from chemical fixation or high-pressure freezing/frozen substitution. Such a PM localization suggests an additional role of VSR proteins in mediating protein transport to PM and endocytosis in growing pollen tubes. Using a high-speed Spinning Disc Confocal Microscope, the possible fusion between VSR-positive PVC organelles and the PM was also observed in living tobacco pollen tubes transiently expressing the PVC reporter GFP-VSR. In contrast, the lack of a prominent PM localization of GFP-VSR in living pollen tubes may be due to the highly dynamic situation of vesicular transport in this fast-growing cell type.
Collapse
Affiliation(s)
- Hao Wang
- School of Life Sciences, Centre for Cell and Developmental Biology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | | | | | | | | |
Collapse
|
48
|
Li HJ, Xue Y, Jia DJ, Wang T, hi DQ, Liu J, Cui F, Xie Q, Ye D, Yang WC. POD1 regulates pollen tube guidance in response to micropylar female signaling and acts in early embryo patterning in Arabidopsis. THE PLANT CELL 2011; 23:3288-302. [PMID: 21954464 PMCID: PMC3203432 DOI: 10.1105/tpc.111.088914] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The pollen tube germinates from pollen and, during its migration, it perceives and responds to guidance cues from maternal tissue and from the female gametophyte. The putative female cues have recently been identified, but how the pollen tube responds to these signals remains to be unveiled. In a genetic screen for male determinants of the pollen tube response, we identified the pollen defective in guidance1 (pod1) mutant, in which the pollen tubes fail to target the female gametophyte. POD1 encodes a conserved protein of unknown function and is essential for positioning and orienting the cell division plane during early embryo development. Here, we demonstrate that POD1 is an endoplasmic reticulum (ER) luminal protein involved in ER protein retention. Further analysis shows that POD1 interacts with the Ca(2+) binding ER chaperone CALRETICULIN3 (CRT3), a protein in charge of folding of membrane receptors. We propose that POD1 modulates the activity of CRT3 or other ER resident factors to control the folding of proteins, such as membrane proteins in the ER. By this mechanism, POD1 may regulate the pollen tube response to signals from the female tissues during pollen tube guidance and early embryo patterning in Arabidopsis thaliana.
Collapse
Affiliation(s)
- Hong-Ju Li
- State Key Laboratory of Molecular and Developmental Biology, National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- Graduate University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yong Xue
- State Key Laboratory of Molecular and Developmental Biology, National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- Graduate University of Chinese Academy of Sciences, Beijing 100049, China
| | - Dong-Jie Jia
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 1000193, China
| | - Tong Wang
- State Key Laboratory of Molecular and Developmental Biology, National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- Graduate University of Chinese Academy of Sciences, Beijing 100049, China
| | - Dong-Qiao hi
- State Key Laboratory of Molecular and Developmental Biology, National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Jie Liu
- State Key Laboratory of Molecular and Developmental Biology, National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Feng Cui
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Qi Xie
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - De Ye
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 1000193, China
| | - Wei-Cai Yang
- State Key Laboratory of Molecular and Developmental Biology, National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- Address correspondence to
| |
Collapse
|
49
|
Bou Daher F, Geitmann A. Actin is Involved in Pollen Tube Tropism Through Redefining the Spatial Targeting of Secretory Vesicles. Traffic 2011; 12:1537-51. [DOI: 10.1111/j.1600-0854.2011.01256.x] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
|
50
|
Qin Y, Yang Z. Rapid tip growth: insights from pollen tubes. Semin Cell Dev Biol 2011; 22:816-24. [PMID: 21729760 DOI: 10.1016/j.semcdb.2011.06.004] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2011] [Revised: 06/16/2011] [Accepted: 06/17/2011] [Indexed: 12/31/2022]
Abstract
Pollen tubes extend rapidly in an oscillatory manner by the extreme form of polarized growth, tip growth, and provide an exciting system for studying the spatiotemporal control of polarized cell growth. The Rho-family ROP GTPase is a key signaling molecule in this growth control and is periodically activated at the apical plasma membrane to spatially define the apical growth region and temporally precede the burst of growth. The spatiotemporal dynamics of ROP GTPase is interconnected with actin dynamics and polar exocytosis that is required for tip-targeted membrane and wall expansion. Recent advances in the study of the mechanistic interlinks between ROP-centered signaling and spatiotemporal dynamics of cell membrane and wall remodeling will be discussed.
Collapse
Affiliation(s)
- Yuan Qin
- Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | | |
Collapse
|