1
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Li X, Bruckmann A, Dresselhaus T, Begcy K. Heat stress at the bicellular stage inhibits sperm cell development and transport into pollen tubes. PLANT PHYSIOLOGY 2024; 195:2111-2128. [PMID: 38366643 PMCID: PMC11213256 DOI: 10.1093/plphys/kiae087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 01/18/2024] [Accepted: 01/23/2024] [Indexed: 02/18/2024]
Abstract
For successful double fertilization in flowering plants (angiosperms), pollen tubes deliver 2 nonmotile sperm cells toward female gametes (egg and central cell, respectively). Heatwaves, especially during the reproduction period, threaten male gametophyte (pollen) development, resulting in severe yield losses. Using maize (Zea mays) as a crop and grass model system, we found strong seed set reduction when moderate heat stress was applied for 2 d during the uni- and bicellular stages of pollen development. We show that heat stress accelerates pollen development and impairs pollen germination capabilities when applied at the unicellular stage. Heat stress at the bicellular stage impairs sperm cell development and transport into pollen tubes. To understand the course of the latter defects, we used marker lines and analyzed the transcriptomes of isolated sperm cells. Heat stress affected the expression of genes associated with transcription, RNA processing and translation, DNA replication, and the cell cycle. This included the genes encoding centromeric histone 3 (CENH3) and α-tubulin. Most genes that were misregulated encode proteins involved in the transition from metaphase to anaphase during pollen mitosis II. Heat stress also activated spindle assembly check point and meta- to anaphase transition genes in sperm cells. In summary, misregulation of the identified genes during heat stress at the bicellular stage results in sperm cell development and transport defects ultimately leading to sterility.
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Affiliation(s)
- Xingli Li
- Department of Cell Biology and Plant Biochemistry, University of Regensburg, 93053 Regensburg, Germany
| | - Astrid Bruckmann
- Department for Biochemistry I, Biochemistry Centre, University of Regensburg, 93053 Regensburg, Germany
| | - Thomas Dresselhaus
- Department of Cell Biology and Plant Biochemistry, University of Regensburg, 93053 Regensburg, Germany
| | - Kevin Begcy
- Environmental Horticulture Department, University of Florida, Gainesville, FL32611, USA
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2
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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.
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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.
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3
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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.
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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.)
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4
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Pei S, Tao Q, Li W, Qi G, Wang B, Wang Y, Dai S, Shen Q, Wang X, Wu X, Xu S, Theprungsirikul L, Zhang J, Liang L, Liu Y, Chen K, Shen Y, Crawford BM, Cheng M, Zhang Q, Wang Y, Liu H, Yang B, Krichilsky B, Pei J, Song K, Johnson DM, Jiang Z, Wu F, Swift GB, Yang H, Liu Z, Zou X, Vo-Dinh T, Liu F, Pei ZM, Yuan F. Osmosensor-mediated control of Ca 2+ spiking in pollen germination. Nature 2024; 629:1118-1125. [PMID: 38778102 PMCID: PMC11136663 DOI: 10.1038/s41586-024-07445-6] [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: 08/08/2022] [Accepted: 04/19/2024] [Indexed: 05/25/2024]
Abstract
Higher plants survive terrestrial water deficiency and fluctuation by arresting cellular activities (dehydration) and resuscitating processes (rehydration). However, how plants monitor water availability during rehydration is unknown. Although increases in hypo-osmolarity-induced cytosolic Ca2+ concentration (HOSCA) have long been postulated to be the mechanism for sensing hypo-osmolarity in rehydration1,2, the molecular basis remains unknown. Because osmolarity triggers membrane tension and the osmosensing specificity of osmosensing channels can only be determined in vivo3-5, these channels have been classified as a subtype of mechanosensors. Here we identify bona fide cell surface hypo-osmosensors in Arabidopsis and find that pollen Ca2+ spiking is controlled directly by water through these hypo-osmosensors-that is, Ca2+ spiking is the second messenger for water status. We developed a functional expression screen in Escherichia coli for hypo-osmosensitive channels and identified OSCA2.1, a member of the hyperosmolarity-gated calcium-permeable channel (OSCA) family of proteins6. We screened single and high-order OSCA mutants, and observed that the osca2.1/osca2.2 double-knockout mutant was impaired in pollen germination and HOSCA. OSCA2.1 and OSCA2.2 function as hypo-osmosensitive Ca2+-permeable channels in planta and in HEK293 cells. Decreasing osmolarity of the medium enhanced pollen Ca2+ oscillations, which were mediated by OSCA2.1 and OSCA2.2 and required for germination. OSCA2.1 and OSCA2.2 convert extracellular water status into Ca2+ spiking in pollen and may serve as essential hypo-osmosensors for tracking rehydration in plants.
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Affiliation(s)
- Songyu Pei
- College of Horticulture and Landscape, Hunan Agricultural University, Changsha, China
- Department of Biology, Duke University, Durham, NC, USA
- Fitzpatrick Institute for Photonics, Duke University, Durham, NC, USA
- College of Life Sciences, Zhejiang University, Hangzhou, China
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Qi Tao
- College of Life Sciences, Zhejiang University, Hangzhou, China
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Wenke Li
- College of Life Sciences, Zhejiang University, Hangzhou, China
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Guoning Qi
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Borong Wang
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Yan Wang
- College of Horticulture and Landscape, Hunan Agricultural University, Changsha, China
| | - Shiwen Dai
- College of Horticulture and Landscape, Hunan Agricultural University, Changsha, China
| | - Qiujing Shen
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Xi Wang
- College of Life Sciences, Zhejiang University, Hangzhou, China
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Xiaomei Wu
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Shijian Xu
- Department of Biology, Duke University, Durham, NC, USA
| | | | | | - Liang Liang
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Yuantao Liu
- College of Life Sciences, Zhejiang University, Hangzhou, China
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Kena Chen
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Yang Shen
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | | | - Mengjia Cheng
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Qi Zhang
- College of Life Sciences, Zhejiang University, Hangzhou, China
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Yiqi Wang
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Hongli Liu
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Benguang Yang
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | | | - Jessica Pei
- Department of Biology, Duke University, Durham, NC, USA
- Fuqua School of Business, Duke University, Durham, NC, USA
| | - Karen Song
- Department of Biology, Duke University, Durham, NC, USA
| | | | | | - Feihua Wu
- Department of Biology, Duke University, Durham, NC, USA
| | - Gary B Swift
- Department of Physics, Duke University, Durham, NC, USA
| | - Huanghe Yang
- Department of Biochemistry, Duke University, Durham, NC, USA
| | - Zhonghua Liu
- College of Horticulture and Landscape, Hunan Agricultural University, Changsha, China
| | - Xuexiao Zou
- College of Horticulture and Landscape, Hunan Agricultural University, Changsha, China
| | - Tuan Vo-Dinh
- Fitzpatrick Institute for Photonics, Duke University, Durham, NC, USA
| | - Feng Liu
- College of Horticulture and Landscape, Hunan Agricultural University, Changsha, China.
- Department of Biology, Duke University, Durham, NC, USA.
| | - Zhen-Ming Pei
- Department of Biology, Duke University, Durham, NC, USA.
- Fitzpatrick Institute for Photonics, Duke University, Durham, NC, USA.
| | - Fang Yuan
- College of Horticulture and Landscape, Hunan Agricultural University, Changsha, China.
- Department of Biology, Duke University, Durham, NC, USA.
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China.
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5
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Riaz A, Thomas J, Ali HH, Zaheer MS, Ahmad N, Pereira A. High night temperature stress on rice ( Oryza sativa) - insights from phenomics to physiology. A review. FUNCTIONAL PLANT BIOLOGY : FPB 2024; 51:FP24057. [PMID: 38815128 DOI: 10.1071/fp24057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Accepted: 05/12/2024] [Indexed: 06/01/2024]
Abstract
Rice (Oryza sativa ) faces challenges to yield and quality due to urbanisation, deforestation and climate change, which has exacerbated high night temperature (HNT). This review explores the impacts of HNT on the physiological, molecular and agronomic aspects of rice growth. Rise in minimum temperature threatens a potential 41% reduction in rice yield by 2100. HNT disrupts rice growth stages, causing reduced seed germination, biomass, spikelet sterility and poor grain development. Recent findings indicate a 4.4% yield decline for every 1°C increase beyond 27°C, with japonica ecotypes exhibiting higher sensitivity than indica. We examine the relationships between elevated CO2 , nitrogen regimes and HNT, showing that the complexity of balancing positive CO2 effects on biomass with HNT challenges. Nitrogen enrichment proves crucial during the vegetative stage but causes disruption to reproductive stages, affecting grain yield and starch synthesis. Additionally, we elucidate the impact of HNT on plant respiration, emphasising mitochondrial respiration, photorespiration and antioxidant responses. Genomic techniques, including CRISPR-Cas9, offer potential for manipulating genes for HNT tolerance. Plant hormones and carbohydrate enzymatic activities are explored, revealing their intricate roles in spikelet fertility, grain size and starch metabolism under HNT. Gaps in understanding genetic factors influencing heat tolerance and potential trade-offs associated with hormone applications remain. The importance of interdisciplinary collaboration is needed to provide a holistic approach. Research priorities include the study of regulatory mechanisms, post-anthesis effects, cumulative HNT exposure and the interaction between climate variability and HNT impact to provide a research direction to enhance rice resilience in a changing climate.
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Affiliation(s)
- Awais Riaz
- Department of Crop, Soil, and Environmental Sciences, Faculty of Agriculture Food and Life Sciences, University of Arkansas System Division of Agriculture, Fayetteville, AR 72701, USA
| | - Julie Thomas
- Department of Crop, Soil, and Environmental Sciences, Faculty of Agriculture Food and Life Sciences, University of Arkansas System Division of Agriculture, Fayetteville, AR 72701, USA
| | - Hafiz Haider Ali
- Department of Crop, Soil, and Environmental Sciences, Faculty of Agriculture Food and Life Sciences, University of Arkansas System Division of Agriculture, Fayetteville, AR 72701, USA; and Department of Agriculture, Government College University Lahore, Lahore 54000, Pakistan; and Department of Plant Sciences, Aberdeen Research & Extension Center, University of Idaho, Aberdeen, ID, USA
| | - Muhammad Saqlain Zaheer
- Department of Agricultural Engineering, Khwaja Fareed University of Engineering and Information Technology, Rahim Yar Khan, Pakistan
| | - Naushad Ahmad
- Department of Chemistry, College of Science, King Saud University, Riyadh11451, Saudi Arabia
| | - Andy Pereira
- Department of Crop, Soil, and Environmental Sciences, Faculty of Agriculture Food and Life Sciences, University of Arkansas System Division of Agriculture, Fayetteville, AR 72701, USA
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6
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Wiese AJ, Torutaeva E, Honys D. The transcription factors and pathways underpinning male reproductive development in Arabidopsis. FRONTIERS IN PLANT SCIENCE 2024; 15:1354418. [PMID: 38390292 PMCID: PMC10882072 DOI: 10.3389/fpls.2024.1354418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 01/15/2024] [Indexed: 02/24/2024]
Abstract
As Arabidopsis flowers mature, specialized cells within the anthers undergo meiosis, leading to the production of haploid microspores that differentiate into mature pollen grains, each containing two sperm cells for double fertilization. During pollination, the pollen grains are dispersed from the anthers to the stigma for subsequent fertilization. Transcriptomic studies have identified a large number of genes expressed over the course of male reproductive development and subsequent functional characterization of some have revealed their involvement in floral meristem establishment, floral organ growth, sporogenesis, meiosis, microsporogenesis, and pollen maturation. These genes encode a plethora of proteins, ranging from transcriptional regulators to enzymes. This review will focus on the regulatory networks that control male reproductive development, starting from flower development and ending with anther dehiscence, with a focus on transcription factors and some of their notable target genes.
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Affiliation(s)
- Anna Johanna Wiese
- Laboratory of Pollen Biology, Institute for Experimental Botany of the Czech Academy of Sciences, Prague, Czechia
| | - Elnura Torutaeva
- Laboratory of Pollen Biology, Institute for Experimental Botany of the Czech Academy of Sciences, Prague, Czechia
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
| | - David Honys
- Laboratory of Pollen Biology, Institute for Experimental Botany of the Czech Academy of Sciences, Prague, Czechia
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
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7
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Kato M, Watari M, Tsuge T, Zhong S, Gu H, Qu LJ, Fujiwara T, Aoyama T. Redundant function of the Arabidopsis phosphatidylinositol 4-phosphate 5-kinase genes PIP5K4-6 is essential for pollen germination. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 117:212-225. [PMID: 37828913 DOI: 10.1111/tpj.16490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 08/02/2023] [Accepted: 09/05/2023] [Indexed: 10/14/2023]
Abstract
Phosphatidylinositol 4-phosphate 5-kinase (PIP5K) is a key enzyme producing the signaling lipid phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2 ] in eukaryotes. Although PIP5K genes are reported to be involved in pollen tube germination and growth, the essential roles of PIP5K in these processes remain unclear. Here, we performed a comprehensive genetic analysis of the Arabidopsis thaliana PIP5K4, PIP5K5, and PIP5K6 genes and revealed that their redundant function is essential for pollen germination. Pollen with the pip5k4pip5k5pip5k6 triple mutation was sterile, while pollen germination efficiency and pollen tube growth were reduced in the pip5k6 single mutant and further reduced in the pip5k4pip5k6 and pip5k5pip5k6 double mutants. YFP-fusion proteins, PIP5K4-YFP, PIP5K5-YFP, and PIP5K6-YFP, which could rescue the sterility of the triple mutant pollen, preferentially localized to the tricolpate aperture area and the future germination site on the plasma membrane prior to germination. Triple mutant pollen grains under the germination condition, in which spatiotemporal localization of the PtdIns(4,5)P2 fluorescent marker protein 2xmCHERRY-2xPHPLC as seen in the wild type was abolished, exhibited swelling and rupture of the pollen wall, but neither the conspicuous protruding site nor site-specific deposition of cell wall materials for germination. These data indicate that PIP5K4-6 and their product PtdIns(4,5)P2 are essential for pollen germination, possibly through the establishment of the germination polarity in a pollen grain.
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Affiliation(s)
- Mariko Kato
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan
| | - Machiko Watari
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan
| | - Tomohiko Tsuge
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan
| | - Sheng Zhong
- Peking-Tsinghua Center for Life Sciences, College of Life Sciences, Peking University, Beijing, 100871, China
| | - Hongya Gu
- Peking-Tsinghua Center for Life Sciences, College of Life Sciences, Peking University, Beijing, 100871, China
| | - Li-Jia Qu
- Peking-Tsinghua Center for Life Sciences, College of Life Sciences, Peking University, Beijing, 100871, China
| | - Takashi Fujiwara
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan
| | - Takashi Aoyama
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan
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8
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Li T, Zhu S, Li Y, Yao J, Wang C, Fang S, Pan J, Chen W, Zhang Y. Characteristic of GEX1 genes reveals the essential roles for reproduction in cotton. Int J Biol Macromol 2023; 253:127645. [PMID: 37879575 DOI: 10.1016/j.ijbiomac.2023.127645] [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: 07/21/2023] [Revised: 09/30/2023] [Accepted: 10/22/2023] [Indexed: 10/27/2023]
Abstract
GEX1 (gamete expressed 1) proteins are critical membrane proteins conserved among flowering plants that are involved in the nuclear fusion and embryonic development. Herein, we identified the 32 GEX1 proteins from representative land plants. In cotton, GEX1 genes expressed in various tissues across all stages of the life cycle, especially in pollen. Subcellular localization indicated the position of GhGEX1 protein was localized in the endoplasmic reticulum. Experimental research has demonstrated that GhGEX1 has the potential to improve the partial abortion phenotype in Arabidopsis. CRISPR/Cas9-mediated knockout of GhGEX1 exhibited the seed abortion. Paraffin section of the ovule revealed that the polar nuclear fusion of ghgex1 plants remains at a standstill when the wild type has developed into a normal embryo. Comparative transcriptome analysis showed that the DEGs of reproductive-related processes and membrane-related processes were repressed in the pollen of knockout lines. The predicted protein interactions showed that GhGEX1 probably functioned through interactions with proteins related to reproduction and membrane. From all these investigations, it was possible to conclude that the GEX1 proteins are evolutionarily conserved in flowering plants and elucidated the pivotal roles during fertilization and early embryonic development in cotton.
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Affiliation(s)
- Tengyu Li
- National Key Laboratory of Cotton Bio-breeding and Integrated Utilization, Institute of Cotton Research, Chinese Academy of Agricultural Science, Anyang 455000, China; National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
| | - Shouhong Zhu
- National Key Laboratory of Cotton Bio-breeding and Integrated Utilization, Institute of Cotton Research, Chinese Academy of Agricultural Science, Anyang 455000, China
| | - Yan Li
- National Key Laboratory of Cotton Bio-breeding and Integrated Utilization, Institute of Cotton Research, Chinese Academy of Agricultural Science, Anyang 455000, China
| | - Jinbo Yao
- National Key Laboratory of Cotton Bio-breeding and Integrated Utilization, Institute of Cotton Research, Chinese Academy of Agricultural Science, Anyang 455000, China
| | - Chenlei Wang
- National Key Laboratory of Cotton Bio-breeding and Integrated Utilization, Institute of Cotton Research, Chinese Academy of Agricultural Science, Anyang 455000, China
| | - Shengtao Fang
- National Key Laboratory of Cotton Bio-breeding and Integrated Utilization, Institute of Cotton Research, Chinese Academy of Agricultural Science, Anyang 455000, China
| | - Jingwen Pan
- National Key Laboratory of Cotton Bio-breeding and Integrated Utilization, Institute of Cotton Research, Chinese Academy of Agricultural Science, Anyang 455000, China
| | - Wei Chen
- National Key Laboratory of Cotton Bio-breeding and Integrated Utilization, Institute of Cotton Research, Chinese Academy of Agricultural Science, Anyang 455000, China.
| | - Yongshan Zhang
- National Key Laboratory of Cotton Bio-breeding and Integrated Utilization, Institute of Cotton Research, Chinese Academy of Agricultural Science, Anyang 455000, China.
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9
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Saito M, Momiki R, Ebine K, Yoshitake Y, Nishihama R, Miyakawa T, Nakano T, Mitsuda N, Araki T, Kohchi T, Yamaoka S. A bHLH heterodimer regulates germ cell differentiation in land plant gametophytes. Curr Biol 2023; 33:4980-4987.e6. [PMID: 37776860 DOI: 10.1016/j.cub.2023.09.020] [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: 06/03/2023] [Revised: 08/20/2023] [Accepted: 09/07/2023] [Indexed: 10/02/2023]
Abstract
Land plants are a monophyletic group of photosynthetic eukaryotes that diverged from streptophyte algae about 470 million years ago. During both the alternating haploid and diploid stages of the life cycle, land plants form multicellular bodies.1,2,3,4 The haploid multicellular body (gametophyte) produces progenitor cells that give rise to gametes and the reproductive organs.5,6,7,8 In the liverwort Marchantia polymorpha, differentiation of the initial cells of gamete-producing organs (gametangia) from the gametophyte is regulated by MpBONOBO (MpBNB), a member of the basic helix-loop-helix (bHLH) transcription factor subfamily VIIIa. In Arabidopsis thaliana, specification of generative cells in developing male gametophytes (pollen) requires redundant action of BNB1 and BNB2.9 Subfamily XI bHLHs, such as LOTUS JAPONICUS ROOTHAIRLESS LIKE1 (LRL1)/DEFECTIVE REGION OF POLLEN1 (DROP1) and LRL2/DROP2 in A. thaliana and the single LRL/DROP protein MpLRL in M. polymorpha, are the evolutionarily conserved regulators of rooting system development.10 Although the role of LRL1/DROP1 and LRL2/DROP2 in gametogenesis remains unclear, their loss leads to the formation of abnormal pollen devoid of sperm cells.11 Here, we show that BNBs and LRL/DROPs co-localize to gametophytic cell nuclei and form heterodimers. LRL1/DROP1 and LRL2/DROP2 act redundantly to regulate BNB expression for generative cell specification in A. thaliana after asymmetric division of the haploid microspore. MpLRL is required for differentiation of MpBNB-expressing gametangium initial cells in M. polymorpha gametophytes. Our findings suggest that broadly expressed LRL/DROP stabilizes BNB expression, leading to the formation of an evolutionarily conserved bHLH heterodimer, which regulates germ cell differentiation in the haploid gametophyte of land plants.
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Affiliation(s)
- Misaki Saito
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Ryosuke Momiki
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Kazuo Ebine
- National Institute for Basic Biology (NIBB), Okazaki, Aichi 444-8585, Japan; The Graduate University for Advanced Studies, SOKENDAI, Okazaki, Aichi 444-8585, Japan
| | | | - Ryuichi Nishihama
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan; Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, Noda, Chiba 278-8510, Japan
| | - Takuya Miyakawa
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Takeshi Nakano
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Nobutaka Mitsuda
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8566, Japan
| | - Takashi Araki
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Takayuki Kohchi
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Shohei Yamaoka
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan.
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10
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Ramming A, Kappel C, Kanaoka MM, Higashiyama T, Lenhard M. Poly(A) polymerase 1 contributes to competence acquisition of pollen tubes growing through the style in Arabidopsis thaliana. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 114:651-667. [PMID: 36811355 DOI: 10.1111/tpj.16162] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 02/16/2023] [Indexed: 05/10/2023]
Abstract
Polyadenylation of mRNAs is critical for their export from the nucleus, stability, and efficient translation. The Arabidopsis thaliana genome encodes three isoforms of canonical nuclear poly(A) polymerase (PAPS) that redundantly polyadenylate the bulk of pre-mRNAs. However, previous studies have indicated that subsets of pre-mRNAs are preferentially polyadenylated by either PAPS1 or the other two isoforms. Such functional specialization raises the possibility of an additional level of gene-expression control in plants. Here we test this notion by studying the function of PAPS1 in pollen-tube growth and guidance. Pollen tubes growing through female tissue acquire the competence to find ovules efficiently and upregulate PAPS1 expression at the transcriptional, but not detectably at the protein level compared with in vitro grown pollen tubes. Using the temperature-sensitive paps1-1 allele we show that PAPS1 activity during pollen-tube growth is required for full acquisition of competence, resulting in inefficient fertilization by paps1-1 mutant pollen tubes. While these mutant pollen tubes grow almost at the wild-type rate, they are compromised in locating the micropyles of ovules. Previously identified competence-associated genes are less expressed in paps1-1 mutant than in wild-type pollen tubes. Estimating the poly(A) tail lengths of transcripts suggests that polyadenylation by PAPS1 is associated with reduced transcript abundance. Our results therefore suggest that PAPS1 plays a key role in the acquisition of competence and underline the importance of functional specialization between PAPS isoforms throughout different developmental stages.
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Affiliation(s)
- Anna Ramming
- University of Potsdam, Institute of Biochemistry and Biology, Karl-Liebknecht-Str. 24-25, D-14476, Potsdam-Golm, Germany
| | - Christian Kappel
- University of Potsdam, Institute of Biochemistry and Biology, Karl-Liebknecht-Str. 24-25, D-14476, Potsdam-Golm, Germany
| | - Masahiro M Kanaoka
- Prefectural University of Hiroshima, Faculty of Life and Environmental Sciences, Faculty of Bioresource Sciences, Shobara, Hiroshima, Japan
| | - Tetsuya Higashiyama
- The University of Tokyo Graduate School of Science, Faculty of Science, Bunkyo-ku, Tokyo, Japan
| | - Michael Lenhard
- University of Potsdam, Institute of Biochemistry and Biology, Karl-Liebknecht-Str. 24-25, D-14476, Potsdam-Golm, Germany
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11
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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.
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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.
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12
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Li H, Feng B, Li J, Fu W, Wang W, Chen T, Liu L, Wu Z, Peng S, Tao L, Fu G. RGA1 alleviates low-light-repressed pollen tube elongation by improving the metabolism and allocation of sugars and energy. PLANT, CELL & ENVIRONMENT 2023; 46:1363-1383. [PMID: 36658612 DOI: 10.1111/pce.14547] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 01/08/2023] [Accepted: 01/18/2023] [Indexed: 06/17/2023]
Abstract
Low-light stress compromises photosynthetic and energy efficiency and leads to spikelet sterility; however, the effect of low-light stress on pollen tube elongation in the pistil remains poorly understood. The gene RGA1, which encodes a Gα-subunit of the heterotrimeric G-protein, enhanced low-light tolerance at anthesis by preventing the cessation of pollen tube elongation in the pistil of rice plants. In this process, marked increases in the activities of acid invertase (INV), sucrose synthase (SUS) and mitochondrial respiratory electron transport chain complexes, as well as the relative expression levels of SUTs (sucrose transporter), SWEETs (sugars will eventually be exported transporters), SUSs, INVs, CINs (cell-wall INV 1), SnRK1A (sucrose-nonfermenting 1-related kinase 1) and SnRK1B, were observed in OE-1 plants. Accordingly, notable increases in contents of ATP and ATPase were presented in OE-1 plants under low-light conditions, while they were decreased in d1 plants. Importantly, INV and ATPase activators (sucrose and Na2 SO3 , respectively) increased spikelet fertility by improving the energy status in the pistil under low-light conditions, and the ATPase inhibitor Na2 VO4 induced spikelet sterility and decreased ATPase activity. These results suggest that RGA1 could alleviate the low-light stress-induced impairment of pollen tube elongation to increase spikelet fertility by promoting sucrose unloading in the pistil and improving the metabolism and allocation of energy.
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Affiliation(s)
- Hubo Li
- National Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, China
- Crop Production and Physiology Center (CPPC), College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Baohua Feng
- National Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, China
| | - Juncai Li
- National Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, China
- Agronomy College, Jilin Agricultural University, Changchun, China
| | - Weimeng Fu
- National Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, China
| | - Wenting Wang
- National Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, China
| | - Tingting Chen
- National Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, China
| | - Lianmeng Liu
- National Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, China
| | - Zhihai Wu
- Agronomy College, Jilin Agricultural University, Changchun, China
| | - Shaobing Peng
- Crop Production and Physiology Center (CPPC), College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Longxing Tao
- National Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, China
| | - Guanfu Fu
- National Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, China
- Agronomy College, Jilin Agricultural University, Changchun, China
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13
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Zhu D, Wen Y, Yao W, Zheng H, Zhou S, Zhang Q, Qu LJ, Chen X, Wu Z. Distinct chromatin signatures in the Arabidopsis male gametophyte. Nat Genet 2023; 55:706-720. [PMID: 36864100 DOI: 10.1038/s41588-023-01329-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2022] [Accepted: 01/30/2023] [Indexed: 03/04/2023]
Abstract
Epigenetic reprogramming in the germline contributes to the erasure of epigenetic inheritance across generations in mammals but remains poorly characterized in plants. Here we profiled histone modifications throughout Arabidopsis male germline development. We find that the sperm cell has widespread apparent chromatin bivalency, which is established by the acquisition of H3K27me3 or H3K4me3 at pre-existing H3K4me3 or H3K27me3 regions, respectively. These bivalent domains are associated with a distinct transcriptional status. Somatic H3K27me3 is generally reduced in sperm, while dramatic loss of H3K27me3 is observed at only ~700 developmental genes. The incorporation of the histone variant H3.10 facilitates the establishment of sperm chromatin identity without a strong impact on resetting of somatic H3K27me3. Vegetative nuclei harbor thousands of specific H3K27me3 domains at repressed genes, while pollination-related genes are highly expressed and marked by gene body H3K4me3. Our work highlights putative chromatin bivalency and restricted resetting of H3K27me3 at developmental regulators as key features in plant pluripotent sperm.
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Affiliation(s)
- Danling Zhu
- Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Institute of Plant and Food Science, Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
| | - Yi Wen
- Shenzhen Key Laboratory of Gene Regulation and Systems Biology, Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
| | - Wanyue Yao
- Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Institute of Plant and Food Science, Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
| | - Haiyan Zheng
- Center for Advanced Biotechnology and Medicine, Biological Mass Spectrometry Facility, Rutgers University, Piscataway, NJ, USA
| | - Sixian Zhou
- Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Institute of Plant and Food Science, Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
| | - Qiqi Zhang
- Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Institute of Plant and Food Science, Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
| | - Li-Jia Qu
- State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, College of Life Sciences, Peking University, Beijing, China
| | - Xi Chen
- Shenzhen Key Laboratory of Gene Regulation and Systems Biology, Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China.
| | - Zhe Wu
- Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Institute of Plant and Food Science, Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China.
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14
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Shiba Y, Takahashi T, Ohashi Y, Ueda M, Mimuro A, Sugimoto J, Noguchi Y, Igawa T. Behavior of Male Gamete Fusogen GCS1/HAP2 and the Regulation in Arabidopsis Double Fertilization. Biomolecules 2023; 13:biom13020208. [PMID: 36830580 PMCID: PMC9953686 DOI: 10.3390/biom13020208] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 01/16/2023] [Accepted: 01/18/2023] [Indexed: 01/25/2023] Open
Abstract
In the sexual reproduction of flowering plants, two independent fertilization events occur almost simultaneously: two identical sperm cells fuse with either the egg cell or the central cell, resulting in embryo and endosperm development to produce a seed. GCS1/HAP2 is a sperm cell membrane protein essential for plasma membrane fusion with both female gametes. Other sperm membrane proteins, DMP8 and DMP9, are more important for egg cell fertilization than that of the central cell, suggesting its regulatory mechanism in GCS1/HAP2-driving gamete membrane fusion. To assess the GCS1/HAP2 regulatory cascade in the double fertilization system of flowering plants, we produced Arabidopsis transgenic lines expressing different GCS1/HAP2 variants and evaluated the fertilization in vivo. The fertilization pattern observed in GCS1_RNAi transgenic plants implied that sperm cells over the amount of GCS1/HAP2 required for fusion on their surface could facilitate membrane fusion with both female gametes. The cytological analysis of the dmp8dmp9 sperm cell arrested alone in an embryo sac supported GCS1/HAP2 distribution on the sperm surface. Furthermore, the fertilization failures with both female gametes were caused by GCS1/HAP2 secretion from the egg cell. These results provided a possible scenario of GCS1/HAP2 regulation, showing a potential scheme for capturing additional GCS1/HAP2-interacting proteins.
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Affiliation(s)
- Yuka Shiba
- Graduate School of Horticulture, Chiba University, Matsudo 648, Matsudo-shi 271-8510, Japan
| | - Taro Takahashi
- Graduate School of Horticulture, Chiba University, Matsudo 648, Matsudo-shi 271-8510, Japan
| | - Yukino Ohashi
- Graduate School of Horticulture, Chiba University, Matsudo 648, Matsudo-shi 271-8510, Japan
| | - Minako Ueda
- Graduate School of Life Sciences, Department of Ecological Developmental Adaptability Life Sciences, Tohoku University, 2-1-1 Katahira, Sendai 980-8577, Japan
- Suntory Rising Stars Encouragement Program in Life Sciences (SunRiSE), Sendai 980-8578, Japan
| | - Amane Mimuro
- Graduate School of Horticulture, Chiba University, Matsudo 648, Matsudo-shi 271-8510, Japan
| | - Jin Sugimoto
- Graduate School of Horticulture, Chiba University, Matsudo 648, Matsudo-shi 271-8510, Japan
| | - Yuka Noguchi
- Graduate School of Horticulture, Chiba University, Matsudo 648, Matsudo-shi 271-8510, Japan
| | - Tomoko Igawa
- Graduate School of Horticulture, Chiba University, Matsudo 648, Matsudo-shi 271-8510, Japan
- Plant Molecular Science Center, Chiba University, 1-33 Yayoi, Chiba-shi 263-8522, Japan
- Correspondence:
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15
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Motomura K, Sugi N, Takeda A, Yamaoka S, Maruyama D. Possible molecular mechanisms of persistent pollen tube growth without de novo transcription. FRONTIERS IN PLANT SCIENCE 2022; 13:1020306. [PMID: 36507386 PMCID: PMC9729840 DOI: 10.3389/fpls.2022.1020306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 11/04/2022] [Indexed: 06/17/2023]
Abstract
The vegetative cell nucleus proceeds ahead of a pair of sperm cells located beneath the pollen tube tip during germination. The tip-localized vegetative nucleus had been considered to play a pivotal role in the control of directional pollen tube growth and double fertilization. However, we recently reported the female-targeting behavior of pollen tubes from mutant plants, of which the vegetative nucleus and sperm nuclei were artificially immotile. We showed that the apical region of the mutant pollen tubes became physiologically enucleated after the first callose plug formation, indicating the autonomously growing nature of pollen tubes without the vegetative nucleus and sperm cells. Thus, in this study, we further analyzed another Arabidopsis thaliana mutant producing physiologically enucleated pollen tubes and discussed the mechanism by which a pollen tube can grow without de novo transcription from the vegetative nucleus. We propose several possible molecular mechanisms for persistent pollen tube growth, such as the contribution of transcripts before and immediately after germination and the use of persistent transcripts, which may be important for a competitive race among pollen tubes.
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Affiliation(s)
- Kazuki Motomura
- College of Life Sciences, Ritsumeikan University, Kusatsu, Japan
- Japanese Science and Technology Agency, PRESTO, Kawaguchi, Japan
- Institute of Transformative Bio-Molecules, Nagoya University, Nagoya, Japan
| | - Naoya Sugi
- Kihara Institute for Biological Research, Yokohama City University, Yokohama, Japan
| | - Atsushi Takeda
- College of Life Sciences, Ritsumeikan University, Kusatsu, Japan
| | - Shohei Yamaoka
- Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Daisuke Maruyama
- Kihara Institute for Biological Research, Yokohama City University, Yokohama, Japan
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16
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Jiang J, Stührwohldt N, Liu T, Huang Q, Li L, Zhang L, Gu H, Fan L, Zhong S, Schaller A, Qu LJ. Egg cell-secreted aspartic proteases ECS1/2 promote gamete attachment to prioritize the fertilization of egg cells over central cells in Arabidopsis. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2022; 64:2047-2059. [PMID: 36165344 DOI: 10.1111/jipb.13371] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 09/23/2022] [Indexed: 06/16/2023]
Abstract
Double fertilization is an innovative phenomenon in angiosperms, in which one sperm cell first fuses with the egg cell to produce the embryo, and then the other sperm fuses with the central cell to produce the endosperm. However, the molecular mechanism of the preferential fertilization of egg cells is poorly understood. In this study, we report that two egg cell-secreted aspartic proteases, ECS1 and ECS2, play an important role in promoting preferential fertilization of egg cells in Arabidopsis. We show that simultaneous loss of ECS1 and ECS2 function resulted in an approximately 20% reduction in fertility, which can be complemented by the full-length ECS1/2 but not by corresponding active site mutants or by secretion-defective versions of ECS1/2. Detailed phenotypic analysis revealed that the egg cell-sperm cell attachment was compromised in ecs1 ecs2 siliques. Limited pollination assays with cyclin-dependent kinase a1 (cdka;1) pollen showed that preferential egg cell fertilization was impaired in the ecs1 ecs2 mutant. Taken together, these results demonstrate that egg cells secret two aspartic proteases, ECS1 and ECS2, to facilitate the attachment of sperm cells to egg cells so that preferential fertilization of egg cells is achieved. This study reveals the molecular mechanism of preferential fertilization in Arabidopsis thaliana.
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Affiliation(s)
- Jiahao Jiang
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing, 100871, China
| | - Nils Stührwohldt
- Department of Plant Physiology and Biochemistry, Institute of Biology, University of Hohenheim, Stuttgart, 70593, Germany
| | - Tianxu Liu
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing, 100871, China
| | - Qingpei Huang
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing, 100871, China
| | - Ling Li
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing, 100871, China
| | - Li Zhang
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing, 100871, China
| | - Hongya Gu
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing, 100871, China
| | - Liumin Fan
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing, 100871, China
| | - Sheng Zhong
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing, 100871, China
| | - Andreas Schaller
- Department of Plant Physiology and Biochemistry, Institute of Biology, University of Hohenheim, Stuttgart, 70593, Germany
| | - Li-Jia Qu
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing, 100871, China
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17
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Li L, Hou S, Xiang W, Song Z, Wang Y, Zhang L, Li J, Gu H, Dong J, Dresselhaus T, Zhong S, Qu LJ. The egg cell is preferentially fertilized in Arabidopsis double fertilization. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2022; 64:2039-2046. [PMID: 36165373 PMCID: PMC9968529 DOI: 10.1111/jipb.13370] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 09/23/2022] [Indexed: 05/28/2023]
Abstract
In flowering plants (angiosperms), fertilization of the egg cell by one sperm cell produces an embryo, whereas fusion of a second sperm cell with the central cell generates the endosperm. In most angiosperms like Arabidopsis, a pollen grain contains two isomorphic sperm cells required for this double fertilization process. A long-standing unsolved question is whether the two fertilization events have any preference. A tool to address this question is the usage of the cyclin-dependent kinase a1 (cdka;1) mutant pollen, which produces a single sperm-like cell (SLC). Here, we first adopt a complementation-based fluorescence-labeling method to successfully separate and collect cdka;1 mutant pollen containing a single SLC. Single-cell RNA-sequencing analysis revealed that cdka;1 SLCs show a gene expression profile highly similar to that of sperm cells and not to the generative cell, precursor of the two sperm cells. Pollination assays using a limited number of cdka;1 mutant pollen revealed that in 98.2% of the ovules, single fertilization of the egg cell occurred. Pollination of pistils with excessive cdka;1 mutant pollen allowed the delivery of a second SLC via fertilization recovery, which fertilized the central cell, resulting in 20.7% double-fertilized ovules. This indicates that cdka;1 SLCs are able to fertilize both the egg and the central cell. Taken together, our findings have answered a long-standing question and support that preferential fertilization of the egg cell is evident in Arabidopsis.
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Affiliation(s)
- Ling Li
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing 100871, China
| | - Saiying Hou
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing 100871, China
| | - Wei Xiang
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing 100871, China
| | - Zihan Song
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing 100871, China
| | - Yuan Wang
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing 100871, China
| | - Li Zhang
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing 100871, China
| | - Jing Li
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing 100871, China
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, College of Bioscience and Resources Environment, Beijing University of Agriculture, Beijing 102206, China
| | - Hongya Gu
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing 100871, China
- The National Plant Gene Research Center, Beijing 100101, China
| | - Juan Dong
- The Waksman Institute of Microbiology, Rutgers the State University of New Jersey, Piscataway, NJ“2” 08854, USA
| | - Thomas Dresselhaus
- Cell Biology and Plant Biochemistry, University of Regensburg, Regensburg 93053, Germany
| | - Sheng Zhong
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing 100871, China
| | - Li-Jia Qu
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing 100871, China
- The National Plant Gene Research Center, Beijing 100101, China
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18
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Regulators of early maize leaf development inferred from transcriptomes of laser capture microdissection (LCM)-isolated embryonic leaf cells. Proc Natl Acad Sci U S A 2022; 119:e2208795119. [PMID: 36001691 PMCID: PMC9436337 DOI: 10.1073/pnas.2208795119] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The superior photosynthetic efficiency of C4 leaves over C3 leaves is owing to their unique Kranz anatomy, in which the vein is surrounded by one layer of bundle sheath (BS) cells and one layer of mesophyll (M) cells. Kranz anatomy development starts from three contiguous ground meristem (GM) cells, but its regulators and underlying molecular mechanism are largely unknown. To identify the regulators, we obtained the transcriptomes of 11 maize embryonic leaf cell types from five stages of pre-Kranz cells starting from median GM cells and six stages of pre-M cells starting from undifferentiated cells. Principal component and clustering analyses of transcriptomic data revealed rapid pre-Kranz cell differentiation in the first two stages but slow differentiation in the last three stages, suggesting early Kranz cell fate determination. In contrast, pre-M cells exhibit a more prolonged transcriptional differentiation process. Differential gene expression and coexpression analyses identified gene coexpression modules, one of which included 3 auxin transporter and 18 transcription factor (TF) genes, including known regulators of Kranz anatomy and/or vascular development. In situ hybridization of 11 TF genes validated their expression in early Kranz development. We determined the binding motifs of 15 TFs, predicted TF target gene relationships among the 18 TF and 3 auxin transporter genes, and validated 67 predictions by electrophoresis mobility shift assay. From these data, we constructed a gene regulatory network for Kranz development. Our study sheds light on the regulation of early maize leaf development and provides candidate leaf development regulators for future study.
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19
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Cai G. The legacy of kinesins in the pollen tube thirty years later. Cytoskeleton (Hoboken) 2022; 79:8-19. [PMID: 35766009 PMCID: PMC9542081 DOI: 10.1002/cm.21713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Revised: 06/06/2022] [Accepted: 06/27/2022] [Indexed: 11/10/2022]
Abstract
The pollen tube is fundamental in the reproduction of seed plants. Particularly in angiosperms, we now have much information about how it grows, how it senses extracellular signals, and how it converts them into a directional growth mechanism. The expansion of the pollen tube is also related to dynamic cytoplasmic processes based on the cytoskeleton (such as polymerization/depolymerization of microtubules and actin filaments) or motor activity along with the two cytoskeletal systems and is dependent on motor proteins. While a considerable amount of information is available for the actomyosin system in the pollen tube, the role of microtubules in the transport of organelles or macromolecular structures is still quite uncertain despite that 30 years ago the first work on the presence of kinesins in the pollen tube was published. Since then, progress has been made in elucidating the role of kinesins in plant cells. However, their role within the pollen tube is still enigmatic. In this review, I will postulate some roles of kinesins in the pollen tube 30 years after their initial discovery based on information obtained in other plant cells in the meantime. The most concrete hypotheses predict that kinesins in the pollen tube enable the short movement of specific organelles or contribute to generative cell or sperm cell transport, as well as mediate specific steps in the process of endocytosis.
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Affiliation(s)
- Giampiero Cai
- Dipartimento Scienze della Vita, Università di Siena, via Mattioli 4, Siena, Italy
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20
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Chumakov MI, Mazilov SI. Genetic Control of Maize Gynogenesis. RUSS J GENET+ 2022. [DOI: 10.1134/s1022795422040044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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21
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Zhang Y, Steiner AL. Projected climate-driven changes in pollen emission season length and magnitude over the continental United States. Nat Commun 2022; 13:1234. [PMID: 35292649 PMCID: PMC8924258 DOI: 10.1038/s41467-022-28764-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 02/11/2022] [Indexed: 11/20/2022] Open
Abstract
Atmospheric conditions affect the release of anemophilous pollen, and the timing and magnitude will be altered by climate change. As simulated with a pollen emission model and future climate data, warmer end-of-century temperatures (4–6 K) shift the start of spring emissions 10–40 days earlier and summer/fall weeds and grasses 5–15 days later and lengthen the season duration. Phenological shifts depend on the temperature response of individual taxa, with convergence in some regions and divergence in others. Temperature and precipitation alter daily pollen emission maxima by −35 to 40% and increase the annual total pollen emission by 16–40% due to changes in phenology and temperature-driven pollen production. Increasing atmospheric CO2 may increase pollen production, and doubling production in conjunction with climate increases end-of-century emissions up to 200%. Land cover change modifies the distribution of pollen emitters, yet the effects are relatively small (<10%) compared to climate or CO2. These simulations indicate that increasing pollen and longer seasons will increase the likelihood of seasonal allergies. Atmospheric conditions affect the release of anemophilous pollen. Zhang et al. use a pollen emission model together with future climate data to simulate changes in pollen emission. The study shows that climate change driven pollen increase and seasonal changes may increase seasonal allergies
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Affiliation(s)
- Yingxiao Zhang
- Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI, USA.
| | - Allison L Steiner
- Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI, USA.
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22
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Li W, Li Q, Lyu M, Wang Z, Song Z, Zhong S, Gu H, Dong J, Dresselhaus T, Zhong S, Qu LJ. Lack of ethylene does not affect reproductive success and synergid cell death in Arabidopsis. MOLECULAR PLANT 2022; 15:354-362. [PMID: 34740849 PMCID: PMC9066556 DOI: 10.1016/j.molp.2021.11.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 09/08/2021] [Accepted: 11/01/2021] [Indexed: 05/12/2023]
Abstract
The signaling pathway of the gaseous hormone ethylene is involved in plant reproduction, growth, development, and stress responses. During reproduction, the two synergid cells of the angiosperm female gametophyte both undergo programmed cell death (PCD)/degeneration but in a different manner: PCD/degeneration of one synergid facilitates pollen tube rupture and thereby the release of sperm cells, while PCD/degeneration of the other synergid blocks supernumerary pollen tubes. Ethylene signaling was postulated to participate in some of the synergid cell functions, such as pollen tube attraction and the induction of PCD/degeneration. However, ethylene-mediated induction of synergid PCD/degeneration and the role of ethylene itself have not been firmly established. Here, we employed the CRISPR/Cas9 technology to knock out the five ethylene-biosynthesis 1-aminocyclopropane-1-carboxylic acid oxidase (ACO) genes and created Arabidopsis mutants free of ethylene production. The ethylene-free mutant plants showed normal triple responses when treated with ethylene rather than 1-aminocyclopropane-1-carboxylic acid, but had increased lateral root density and enlarged petal sizes, which are typical phenotypes of mutants defective in ethylene signaling. Using these ethylene-free plants, we further demonstrated that production of ethylene is not necessarily required to trigger PCD/degeneration of the two synergid cells, but certain components of ethylene signaling including transcription factors ETHYLENE-INSENSITIVE 3 (EIN3) and EIN3-LIKE 1 (EIL1) are necessary for the death of the persistent synergid cell.
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Affiliation(s)
- Wenhao Li
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing 100871, People's Republic of China
| | - Qiyun Li
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing 100871, People's Republic of China
| | - Mohan Lyu
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing 100871, People's Republic of China
| | - Zhijuan Wang
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing 100871, People's Republic of China
| | - Zihan Song
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing 100871, People's Republic of China
| | - Shangwei Zhong
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing 100871, People's Republic of China
| | - Hongya Gu
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing 100871, People's Republic of China; The National Plant Gene Research Center (Beijing), Beijing 100101, People's Republic of China
| | - Juan Dong
- The Waksman Institute of Microbiology, Rutgers the State University of New Jersey, Piscataway, NJ 08854, USA
| | - Thomas Dresselhaus
- Cell Biology and Plant Biochemistry, University of Regensburg, 93053 Regensburg, Germany
| | - Sheng Zhong
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing 100871, People's Republic of China.
| | - Li-Jia Qu
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing 100871, People's Republic of China; The National Plant Gene Research Center (Beijing), Beijing 100101, People's Republic of China.
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23
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Abstract
Flowering plants alternate between multicellular haploid (gametophyte) and diploid (sporophyte) generations. Pollen actively transcribes its haploid genome, providing phenotypic diversity even among pollen grains from a single plant. In this study, we used allele-specific RNA sequencing of single pollen precursors to follow the shift to haploid expression in maize pollen. We observed widespread biallelic expression for 11 days after meiosis, indicating that transcripts synthesized by the diploid sporophyte persist long into the haploid phase. Subsequently, there was a rapid and global conversion to monoallelic expression at pollen mitosis I, driven by active new transcription from the haploid genome. Genes showed evidence of increased purifying selection if they were expressed after (but not before) pollen mitosis I. This work establishes the timing during which haploid selection may act in pollen.
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Affiliation(s)
- Brad Nelms
- Department of Plant Biology, University of Georgia, Athens, GA 30606, USA
| | - Virginia Walbot
- Department of Biology, Stanford University, Stanford, CA 94305, USA
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24
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Zhong S, Li L, Wang Z, Ge Z, Li Q, Bleckmann A, Wang J, Song Z, Shi Y, Liu T, Li L, Zhou H, Wang Y, Zhang L, Wu HM, Lai L, Gu H, Dong J, Cheung AY, Dresselhaus T, Qu LJ. RALF peptide signaling controls the polytubey block in Arabidopsis. Science 2022; 375:290-296. [PMID: 35050671 PMCID: PMC9040003 DOI: 10.1126/science.abl4683] [Citation(s) in RCA: 45] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Fertilization of an egg by multiple sperm (polyspermy) leads to lethal genome imbalance and chromosome segregation defects. In Arabidopsis thaliana, the block to polyspermy is facilitated by a mechanism that prevents polytubey (the arrival of multiple pollen tubes to one ovule). We show here that FERONIA, ANJEA, and HERCULES RECEPTOR KINASE 1 receptor-like kinases located at the septum interact with pollen tube-specific RALF6, 7, 16, 36, and 37 peptide ligands to establish this polytubey block. The same combination of RALF (rapid alkalinization factor) peptides and receptor complexes controls pollen tube reception and rupture inside the targeted ovule. Pollen tube rupture releases the polytubey block at the septum, which allows the emergence of secondary pollen tubes upon fertilization failure. Thus, orchestrated steps in the fertilization process in Arabidopsis are coordinated by the same signaling components to guarantee and optimize reproductive success.
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Affiliation(s)
- Sheng Zhong
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing 100871, People’s Republic of China
| | - Ling Li
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing 100871, People’s Republic of China
| | - Zhijuan Wang
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing 100871, People’s Republic of China
| | - Zengxiang Ge
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing 100871, People’s Republic of China
| | - Qiyun Li
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing 100871, People’s Republic of China
| | - Andrea Bleckmann
- Cell Biology and Plant Biochemistry, University of Regensburg, 93053 Regensburg, Germany
| | - Jizong Wang
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing 100871, People’s Republic of China
| | - Zihan Song
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing 100871, People’s Republic of China
| | - Yihao Shi
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing 100871, People’s Republic of China
| | - Tianxu Liu
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing 100871, People’s Republic of China
| | - Luhan Li
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing 100871, People’s Republic of China
| | - Huabin Zhou
- College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, People’s Republic of China
| | - Yanyan Wang
- College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, People’s Republic of China
| | - Li Zhang
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing 100871, People’s Republic of China
| | - Hen-Ming Wu
- Department of Biochemistry and Molecular Biology, Molecular and Cell Biology Program, Plant Biology Program, University of Massachusetts, Amherst, MA 01003, USA
| | - Luhua Lai
- College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, People’s Republic of China
| | - Hongya Gu
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing 100871, People’s Republic of China
- The National Plant Gene Research Center (Beijing), Beijing 100101, People’s Republic of China
| | - Juan Dong
- The Waksman Institute of Microbiology, Rutgers the State University of New Jersey, Piscataway, NJ 08854, USA
| | - Alice Y. Cheung
- Department of Biochemistry and Molecular Biology, Molecular and Cell Biology Program, Plant Biology Program, University of Massachusetts, Amherst, MA 01003, USA
| | - Thomas Dresselhaus
- Cell Biology and Plant Biochemistry, University of Regensburg, 93053 Regensburg, Germany
| | - Li-Jia Qu
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing 100871, People’s Republic of China
- The National Plant Gene Research Center (Beijing), Beijing 100101, People’s Republic of China
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25
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Gutiérrez-Valencia J, Fracassetti M, Horvath R, Laenen B, Désamore A, Drouzas AD, Friberg M, Kolář F, Slotte T. Genomic Signatures of Sexual Selection on Pollen-Expressed Genes in Arabis alpina. Mol Biol Evol 2021; 39:6456311. [PMID: 34878144 PMCID: PMC8788238 DOI: 10.1093/molbev/msab349] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Fertilization in angiosperms involves the germination of pollen on the stigma, followed by the extrusion of a pollen tube that elongates through the style and delivers two sperm cells to the embryo sac. Sexual selection could occur throughout this process when male gametophytes compete for fertilization. The strength of sexual selection during pollen competition should be affected by the number of genotypes deposited on the stigma. As increased self-fertilization reduces the number of mating partners, and the genetic diversity and heterozygosity of populations, it should thereby reduce the intensity of sexual selection during pollen competition. Despite the prevalence of mating system shifts, few studies have directly compared the molecular signatures of sexual selection during pollen competition in populations with different mating systems. Here we analyzed whole-genome sequences from natural populations of Arabis alpina, a species showing mating system variation across its distribution, to test whether shifts from cross- to self-fertilization result in molecular signatures consistent with sexual selection on genes involved in pollen competition. We found evidence for efficient purifying selection on genes expressed in vegetative pollen, and overall weaker selection on sperm-expressed genes. This pattern was robust when controlling for gene expression level and specificity. In agreement with the expectation that sexual selection intensifies under cross-fertilization, we found that the efficacy of purifying selection on male gametophyte-expressed genes was significantly stronger in genetically more diverse and outbred populations. Our results show that intra-sexual competition shapes the evolution of pollen-expressed genes, and that its strength fades with increasing self-fertilization rates.
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Affiliation(s)
- Juanita Gutiérrez-Valencia
- Department of Ecology, Environment, and Plant Sciences, Science for Life Laboratory, Stockholm University, Stockholm, Sweden
| | - Marco Fracassetti
- Department of Ecology, Environment, and Plant Sciences, Science for Life Laboratory, Stockholm University, Stockholm, Sweden
| | - Robert Horvath
- Department of Ecology, Environment, and Plant Sciences, Science for Life Laboratory, Stockholm University, Stockholm, Sweden
| | - Benjamin Laenen
- Department of Ecology, Environment, and Plant Sciences, Science for Life Laboratory, Stockholm University, Stockholm, Sweden
| | - Aurélie Désamore
- Department of Ecology, Environment, and Plant Sciences, Science for Life Laboratory, Stockholm University, Stockholm, Sweden
| | - Andreas D Drouzas
- Laboratory of Systematic Botany and Phytogeography, School of Biology, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Magne Friberg
- Department of Biology, Lund University, Lund, Sweden
| | - Filip Kolář
- Department of Botany, Faculty of Science, Charles University, Prague, Czech Republic
| | - Tanja Slotte
- Department of Ecology, Environment, and Plant Sciences, Science for Life Laboratory, Stockholm University, Stockholm, Sweden
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26
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Huang J, Dong J, Qu LJ. From birth to function: Male gametophyte development in flowering plants. CURRENT OPINION IN PLANT BIOLOGY 2021; 63:102118. [PMID: 34625367 PMCID: PMC9039994 DOI: 10.1016/j.pbi.2021.102118] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 08/13/2021] [Accepted: 08/25/2021] [Indexed: 05/08/2023]
Abstract
Male germline development in flowering plants involves two distinct and successive phases, microsporogenesis and microgametogenesis, which involve one meiosis followed by two rounds of mitosis. Many aspects of distinctions after mitosis between the vegetative cell and the male germ cells are seen, from morphology to structure, and the differential functions of the two cell types in the male gametophyte are differentially needed and required for double fertilization. The two sperm cells, carriers of the hereditary substances, depend on the vegetative cell/pollen tube to be delivered to the female gametophyte for double fertilization. Thus, the intercellular communication and coordinated activity within the male gametophyte probably represent the most subtle regulation in flowering plants to guarantee the success of reproduction. This review will focus on what we have known about the differentiation process and the functional diversification of the vegetative cell and the male germ cell, the most crucial cell types for plant fertility and crop production.
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Affiliation(s)
- Jiaying Huang
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at the College of Life Sciences, Peking University, Beijing 100871, People's Republic of China; Waksman Institute of Microbiology, Rutgers, the State University of New Jersey, Piscataway, NJ 08854, USA; Department of Plant Biology, Rutgers, the State University of New Jersey, Piscataway, NJ 08901, USA
| | - Juan Dong
- Waksman Institute of Microbiology, Rutgers, the State University of New Jersey, Piscataway, NJ 08854, USA; Department of Plant Biology, Rutgers, the State University of New Jersey, Piscataway, NJ 08901, USA.
| | - Li-Jia Qu
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at the College of Life Sciences, Peking University, Beijing 100871, People's Republic of China; The National Plant Gene Research Center (Beijing), Beijing 100101, People's Republic of China.
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27
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Hou S, Shi J, Hao L, Wang Z, Liao Y, Gu H, Dong J, Dresselhaus T, Zhong S, Qu LJ. VPS18-regulated vesicle trafficking controls the secretion of pectin and its modifying enzyme during pollen tube growth in Arabidopsis. THE PLANT CELL 2021; 33:3042-3056. [PMID: 34125904 PMCID: PMC8462820 DOI: 10.1093/plcell/koab164] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 06/03/2021] [Indexed: 05/07/2023]
Abstract
In eukaryotes, homotypic fusion and vacuolar protein sorting (HOPS) as well as class C core vacuole/endosome tethering (CORVET) are evolutionarily conserved membrane tethering complexes that play important roles in lysosomal/vacuolar trafficking. Whether HOPS and CORVET control endomembrane trafficking in pollen tubes, the fastest growing plant cells, remains largely elusive. In this study, we demonstrate that the four core components shared by the two complexes, Vacuole protein sorting 11 (VPS11), VPS16, VPS33, and VPS18, are all essential for pollen tube growth in Arabidopsis thaliana and thus for plant reproduction success. We used VPS18 as a representative core component of the complexes to show that the protein is localized to both multivesicular bodies (MVBs) and the tonoplast in a growing pollen tube. Mutant vps18 pollen tubes grew more slowly in vivo, resulting in a significant reduction in male transmission efficiency. Additional studies revealed that membrane fusion from MVBs to vacuoles is severely compromised in vps18 pollen tubes, corroborating the function of VPS18 in late endocytic trafficking. Furthermore, vps18 pollen tubes produce excessive exocytic vesicles at the apical zone and excessive amounts of pectin and pectin methylesterases in the cell wall. In conclusion, this study establishes an additional conserved role of HOPS/CORVET in homotypic membrane fusion during vacuole biogenesis in pollen tubes and reveals a feedback regulation of HOPS/CORVET in the secretion of cell wall modification enzymes of rapidly growing plant cells.
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Affiliation(s)
- Saiying Hou
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing 100871, People’s Republic of China
| | - Jiao Shi
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing 100871, People’s Republic of China
| | - Lihong Hao
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing 100871, People’s Republic of China
- School of Life Sciences, Shanxi University, Taiyuan, Shanxi Province 030006, People’s Republic of China
| | - Zhijuan Wang
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing 100871, People’s Republic of China
| | - Yalan Liao
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing 100871, People’s Republic of China
| | - Hongya Gu
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing 100871, People’s Republic of China
| | - Juan Dong
- The Waksman Institute of Microbiology, Rutgers the State University of New Jersey, Piscataway, New Jersey 08854, USA
| | - Thomas Dresselhaus
- Cell Biology and Plant Biochemistry, University of Regensburg, 93053 Regensburg, Germany
| | - Sheng Zhong
- Author for correspondence: (S.Z.), (L.-J.Q.)
| | - Li-Jia Qu
- Author for correspondence: (S.Z.), (L.-J.Q.)
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28
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Arshad W, Lenser T, Wilhelmsson PKI, Chandler JO, Steinbrecher T, Marone F, Pérez M, Collinson ME, Stuppy W, Rensing SA, Theißen G, Leubner-Metzger G. A tale of two morphs: developmental patterns and mechanisms of seed coat differentiation in the dimorphic diaspore model Aethionema arabicum (Brassicaceae). THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 107:166-181. [PMID: 33945185 DOI: 10.1111/tpj.15283] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 04/15/2021] [Indexed: 06/12/2023]
Abstract
The developmental transition from a fertilized ovule to a dispersed diaspore (seed or fruit) involves complex differentiation processes of the ovule's integuments leading to the diversity in mature seed coat structures in angiosperms. In this study, comparative imaging and transcriptome analysis were combined to investigate the morph-specific developmental differences during outer seed coat differentiation and mucilage production in Aethionema arabicum, the Brassicaceae model for diaspore dimorphism. One of the intriguing adaptations of this species is the production and dispersal of morphologically distinct, mucilaginous and non-mucilaginous diaspores from the same plant (dimorphism). The dehiscent fruit morph programme producing multiple mucilaginous seed diaspores was used as the default trait combination, similar to Arabidopsis thaliana, and was compared with the indehiscent fruit morph programme leading to non-mucilaginous diaspores. Synchrotron-based radiation X-ray tomographic microscopy revealed a co-ordinated framework of morph-specific early changes in internal anatomy of developing A. arabicum gynoecia including seed abortion in the indehiscent programme and mucilage production by the mucilaginous seed coat. The associated comparative analysis of the gene expression patterns revealed that the unique seed coat dimorphism of Ae. arabicum provides an excellent model system for comparative study of the control of epidermal cell differentiation and mucilage biosynthesis by the mucilage transcription factor cascade and their downstream cell wall and mucilage remodelling genes. Elucidating the underlying molecular framework of the dimorphic diaspore syndrome is key to understanding differential regulation of bet-hedging survival strategies in challenging environments, timely in the face of global climatic change.
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Affiliation(s)
- Waheed Arshad
- Department of Biological Sciences, Royal Holloway University of London, Egham, TW20 0EX, UK
| | - Teresa Lenser
- Matthias Schleiden Institute/Genetics, Friedrich Schiller University Jena, Jena, D-07743, Germany
| | - Per K I Wilhelmsson
- Plant Cell Biology, Department of Biology, University of Marburg, Marburg, D-35043, Germany
| | - Jake O Chandler
- Department of Biological Sciences, Royal Holloway University of London, Egham, TW20 0EX, UK
| | - Tina Steinbrecher
- Department of Biological Sciences, Royal Holloway University of London, Egham, TW20 0EX, UK
| | - Federica Marone
- Swiss Light Source, Paul Scherrer Institute, Villigen, CH-5232, Switzerland
| | - Marta Pérez
- Department of Biological Sciences, Royal Holloway University of London, Egham, TW20 0EX, UK
| | - Margaret E Collinson
- Department of Earth Sciences, Royal Holloway University of London, Egham, TW20 0EX, UK
| | - Wolfgang Stuppy
- Botanischer Garten der Ruhr-Universität Bochum, Universitätsstraße 150, Bochum, D-44780, Germany
- The Royal Botanic Gardens, Kew, Wellcome Trust Millennium Building, Wakehurst Place, Ardingly, West Sussex, RH17 6TN, UK
| | - Stefan A Rensing
- Plant Cell Biology, Department of Biology, University of Marburg, Marburg, D-35043, Germany
| | - Günter Theißen
- Matthias Schleiden Institute/Genetics, Friedrich Schiller University Jena, Jena, D-07743, Germany
| | - Gerhard Leubner-Metzger
- Department of Biological Sciences, Royal Holloway University of London, Egham, TW20 0EX, UK
- Laboratory of Growth Regulators, Palacký University, Institute of Experimental Botany, Czech Academy of Sciences, Olomouc, CZ-78371, Czech Republic
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29
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Abstract
The gametophyte represents the sexual phase in the alternation of generations in plants; the other, nonsexual phase is the sporophyte. Here, we review the evolutionary origins of the male gametophyte among land plants and, in particular, its ontogenesis in flowering plants. The highly reduced male gametophyte of angiosperm plants is a two- or three-celled pollen grain. Its task is the production of two male gametes and their transport to the female gametophyte, the embryo sac, where double fertilization takes place. We describe two phases of pollen ontogenesis-a developmental phase leading to the differentiation of the male germline and the formation of a mature pollen grain and a functional phase representing the pollen tube growth, beginning with the landing of the pollen grain on the stigma and ending with double fertilization. We highlight recent advances in the complex regulatory mechanisms involved, including posttranscriptional regulation and transcript storage, intracellular metabolic signaling, pollen cell wall structure and synthesis, protein secretion, and phased cell-cell communication within the reproductive tissues.
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Affiliation(s)
- Said Hafidh
- Laboratory of Pollen Biology, Institute of Experimental Botany of the Czech Academy of Sciences, 165 02 Prague 6, Czech Republic; ,
| | - David Honys
- Laboratory of Pollen Biology, Institute of Experimental Botany of the Czech Academy of Sciences, 165 02 Prague 6, Czech Republic; ,
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30
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Liu M, Wang Z, Hou S, Wang L, Huang Q, Gu H, Dresselhaus T, Zhong S, Qu LJ. AtLURE1/PRK6-mediated signaling promotes conspecific micropylar pollen tube guidance. PLANT PHYSIOLOGY 2021; 186:865-873. [PMID: 33638984 PMCID: PMC8195523 DOI: 10.1093/plphys/kiab105] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 02/11/2021] [Indexed: 05/16/2023]
Abstract
Reproductive isolation is a prerequisite to form and maintain a new species. Multiple prezygotic and postzygotic reproductive isolation barriers have been reported in plants. In the model plant, Arabidopsis thaliana conspecific pollen tube precedence controlled by AtLURE1/PRK6-mediated signaling has been recently reported as a major prezygotic reproductive isolation barrier. By accelerating emergence of own pollen tubes from the transmitting tract, A. thaliana ovules promote self-fertilization and thus prevent fertilization by a different species. Taking advantage of a septuple atlure1null mutant, we now report on the role of AtLURE1/PRK6-mediated signaling for micropylar pollen tube guidance. Compared with wild-type (WT) ovules, atlure1null ovules displayed remarkably reduced micropylar pollen tube attraction efficiencies in modified semi-in vivo A. thaliana ovule targeting assays. However, when prk6 mutant pollen tubes were applied, atlure1null ovules showed micropylar attraction efficiencies comparable to that of WT ovules. These findings indicate that AtLURE1/PRK6-mediated signaling regulates micropylar pollen tube attraction in addition to promoting emergence of own pollen tubes from the transmitting tract. Moreover, semi-in vivo ovule targeting competition assays with the same amount of pollen grains from both A. thaliana and Arabidopsis lyrata showed that A. thaliana WT and xiuqiu mutant ovules are mainly targeted by own pollen tubes and that atlure1null mutant ovules are also entered to a large extent by A. lyrata pollen tubes. Taken together, we report that AtLURE1/PRK6-mediated signaling promotes conspecific micropylar pollen tube attraction representing an additional prezygotic isolation barrier.
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Affiliation(s)
- Meiling Liu
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at the College of Life Sciences, Peking University, Beijing 100871, People’s Republic of China
| | - Zhijuan Wang
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at the College of Life Sciences, Peking University, Beijing 100871, People’s Republic of China
| | - Saiying Hou
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at the College of Life Sciences, Peking University, Beijing 100871, People’s Republic of China
| | - Lele Wang
- Cell Biology and Plant Biochemistry, University of Regensburg, 93053 Regensburg, Germany
| | - Qingpei Huang
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at the College of Life Sciences, Peking University, Beijing 100871, People’s Republic of China
| | - Hongya Gu
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at the College of Life Sciences, Peking University, Beijing 100871, People’s Republic of China
- The National Plant Gene Research Center (Beijing), Beijing 100101, People’s Republic of China
| | - Thomas Dresselhaus
- Cell Biology and Plant Biochemistry, University of Regensburg, 93053 Regensburg, Germany
| | - Sheng Zhong
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at the College of Life Sciences, Peking University, Beijing 100871, People’s Republic of China
| | - Li-Jia Qu
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at the College of Life Sciences, Peking University, Beijing 100871, People’s Republic of China
- The National Plant Gene Research Center (Beijing), Beijing 100101, People’s Republic of China
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31
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Zhang Y, Mitsuda N, Yoshizumi T, Horii Y, Oshima Y, Ohme-Takagi M, Matsui M, Kakimoto T. Two types of bHLH transcription factor determine the competence of the pericycle for lateral root initiation. NATURE PLANTS 2021; 7:633-643. [PMID: 34007039 DOI: 10.1038/s41477-021-00919-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 04/15/2021] [Indexed: 05/26/2023]
Abstract
The molecular basis of the competence of the pericycle cell to initiate lateral root primordium formation is totally unknown. Here, we report that in Arabidopsis, two types of basic helix-loop-helix (bHLH) transcription factors, named PERICYCLE FACTOR TYPE-A (PFA) proteins and PERICYCLE FACTOR TYPE-B (PFB) proteins, govern the competence of pericycle cells to initiate lateral root primordium formation. Overexpression of PFA genes confers hallmark pericycle characteristics, including specific marker gene expression and auxin-induced cell division, and multiple loss-of-function mutations in PFA genes or the repression of PFB target genes results in the loss of this specific pericycle function. PFA and PFB proteins physically interact and are under mutual- and self-regulation, forming a positive feedback loop. This study unveils the transcriptional regulatory system that determines pericycle participation in lateral root initiation.
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Affiliation(s)
- Ye Zhang
- Department of Biology, Graduate School of Science, Osaka University, Osaka, Japan
- Graduate School of Science and Technology, Nara Institute of Science and Technology, Nara, Japan
| | - Nobutaka Mitsuda
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
- Global Zero Emission Research Center, AIST, Tsukuba, Japan
| | - Takeshi Yoshizumi
- RIKEN Center for Sustainable Resource Science, Yokohama, Japan
- Takasaki University of Health and Welfare, Takasaki, Japan
| | - Yoko Horii
- RIKEN Center for Sustainable Resource Science, Yokohama, Japan
| | - Yoshimi Oshima
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
| | - Masaru Ohme-Takagi
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
- Greenbio Research Center, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - Minami Matsui
- RIKEN Center for Sustainable Resource Science, Yokohama, Japan
| | - Tatsuo Kakimoto
- Department of Biology, Graduate School of Science, Osaka University, Osaka, Japan.
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32
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Motomura K, Takeuchi H, Notaguchi M, Tsuchi H, Takeda A, Kinoshita T, Higashiyama T, Maruyama D. Persistent directional growth capability in Arabidopsis thaliana pollen tubes after nuclear elimination from the apex. Nat Commun 2021; 12:2331. [PMID: 33888710 PMCID: PMC8062503 DOI: 10.1038/s41467-021-22661-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 03/22/2021] [Indexed: 02/04/2023] Open
Abstract
During the double fertilization process, pollen tubes deliver two sperm cells to an ovule containing the female gametes. In the pollen tube, the vegetative nucleus and sperm cells move together to the apical region where the vegetative nucleus is thought to play a crucial role in controlling the direction and growth of the pollen tube. Here, we report the generation of pollen tubes in Arabidopsis thaliana whose vegetative nucleus and sperm cells are isolated and sealed by callose plugs in the basal region due to apical transport defects induced by mutations in the WPP domain-interacting tail-anchored proteins (WITs) and sperm cell-specific expression of a dominant mutant of the CALLOSE SYNTHASE 3 protein. Through pollen-tube guidance assays, we show that the physiologically anuclear mutant pollen tubes maintain the ability to grow and enter ovules. Our findings provide insight into the sperm cell delivery mechanism and illustrate the independence of the tip-localized vegetative nucleus from directional growth control of the pollen tube.
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Affiliation(s)
- Kazuki Motomura
- Ritsumeikan Global Innovation Research Organization, Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan.,Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8601, Japan.,JST, PRESTO, Kawaguchi, Saitama, 332-0012, Japan
| | - Hidenori Takeuchi
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8601, Japan.,Institute for Advanced Research, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8601, Japan
| | - Michitaka Notaguchi
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8601, Japan.,Bioscience and Biotechnology Center, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8601, Japan
| | - Haruna Tsuchi
- Kihara Institute for Biological Research, Yokohama City University, Maioka-cho, Totsuka-ku, Yokohama, Kanagawa, 244-0813, Japan
| | - Atsushi Takeda
- Ritsumeikan Global Innovation Research Organization, Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan.,College of Life Sciences, Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan
| | - Tetsu Kinoshita
- Kihara Institute for Biological Research, Yokohama City University, Maioka-cho, Totsuka-ku, Yokohama, Kanagawa, 244-0813, Japan
| | - Tetsuya Higashiyama
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8601, Japan.,Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8602, Japan.,Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Daisuke Maruyama
- Kihara Institute for Biological Research, Yokohama City University, Maioka-cho, Totsuka-ku, Yokohama, Kanagawa, 244-0813, Japan.
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33
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Oh SA, Park HJ, Kim MH, Park SK. Analysis of sticky generative cell mutants reveals that suppression of callose deposition in the generative cell is necessary for generative cell internalization and differentiation in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 106:228-244. [PMID: 33458909 DOI: 10.1111/tpj.15162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 01/11/2021] [Indexed: 06/12/2023]
Abstract
In flowering plants, double fertilization between male and female gametophytes, which are separated by distance, largely depends on the unique pattern of the male gametophyte (pollen): two non-motile sperm cells suspended within a tube-producing vegetative cell. A morphological screen to elucidate the genetic control governing the strategic patterning of pollen has led to the isolation of a sticky generative cell (sgc) mutant that dehisces abnormal pollen with the generative cell immobilized at the pollen wall. Analyses revealed that the sgc mutation is specifically detrimental to pollen development, causing ectopic callose deposition that impedes the timely internalization and differentiation of the generative cell. We found that the SGC gene encodes the highly conserved domain of unknown function 707 (DUF707) gene that is broadly expressed but is germline specific during pollen development. Additionally, transgenic plants co-expressing fluorescently fused SGC protein and known organelle markers showed that SGC localizes in the endoplasmic reticulum, Golgi apparatus and vacuoles in pollen. A yeast two-hybrid screen with an SGC bait identified a thaumatin-like protein that we named GCTLP1, some homologs of which bind and/or digest β-1,3-glucans, the main constituent of callose. GCTLP1 is expressed in a germline-specific manner and colocalizes with SGC during pollen development, indicating that GCTLP1 is a putative SGC interactor. Collectively, our results show that SGC suppresses callose deposition in the nascent generative cell, thereby allowing the generative cell to fully internalize into the vegetative cell and correctly differentiate as the germline progenitor, with the potential involvement of the GCTLP1 protein, during pollen development in Arabidopsis.
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Affiliation(s)
- Sung-Aeong Oh
- School of Applied Biosciences, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Hyo-Jin Park
- School of Applied Biosciences, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Myung-Hee Kim
- School of Applied Biosciences, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Soon-Ki Park
- School of Applied Biosciences, Kyungpook National University, Daegu, 41566, Republic of Korea
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34
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Yu X, Zhang X, Zhao P, Peng X, Chen H, Bleckmann A, Bazhenova A, Shi C, Dresselhaus T, Sun MX. Fertilized egg cells secrete endopeptidases to avoid polytubey. Nature 2021; 592:433-437. [PMID: 33790463 DOI: 10.1038/s41586-021-03387-5] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Accepted: 02/24/2021] [Indexed: 11/09/2022]
Abstract
Upon gamete fusion, animal egg cells secrete proteases from cortical granules to establish a fertilization envelope as a block to polyspermy1-4. Fertilization in flowering plants is more complex and involves the delivery of two non-motile sperm cells by pollen tubes5,6. Simultaneous penetration of ovules by multiple pollen tubes (polytubey) is usually avoided, thus indirectly preventing polyspermy7,8. How plant egg cells regulate the rejection of extra tubes after successful fertilization is not known. Here we report that the aspartic endopeptidases ECS1 and ECS2 are secreted to the extracellular space from a cortical network located at the apical domain of the Arabidopsis egg cell. This reaction is triggered only after successful fertilization. ECS1 and ECS2 are exclusively expressed in the egg cell and transcripts are degraded immediately after gamete fusion. ECS1 and ESC2 specifically cleave the pollen tube attractor LURE1. As a consequence, polytubey is frequent in ecs1 ecs2 double mutants. Ectopic secretion of these endopeptidases from synergid cells led to a decrease in the levels of LURE1 and reduced the rate of pollen tube attraction. Together, these findings demonstrate that plant egg cells sense successful fertilization and elucidate a mechanism as to how a relatively fast post-fertilization block to polytubey is established by fertilization-induced degradation of attraction factors.
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Affiliation(s)
- Xiaobo Yu
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Xuecheng Zhang
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Peng Zhao
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Xiongbo Peng
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Hong Chen
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Andrea Bleckmann
- Cell Biology and Plant Biochemistry, University of Regensburg, Regensburg, Germany
| | - Anastasiia Bazhenova
- Cell Biology and Plant Biochemistry, University of Regensburg, Regensburg, Germany
| | - Ce Shi
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Thomas Dresselhaus
- Cell Biology and Plant Biochemistry, University of Regensburg, Regensburg, Germany.
| | - Meng-Xiang Sun
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China.
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35
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Flores-Tornero M, Wang L, Potěšil D, Hafidh S, Vogler F, Zdráhal Z, Honys D, Sprunck S, Dresselhaus T. Comparative analyses of angiosperm secretomes identify apoplastic pollen tube functions and novel secreted peptides. PLANT REPRODUCTION 2021; 34:47-60. [PMID: 33258014 PMCID: PMC7902602 DOI: 10.1007/s00497-020-00399-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 11/10/2020] [Indexed: 05/14/2023]
Abstract
KEY MESSAGE Analyses of secretomes of in vitro grown pollen tubes from Amborella, maize and tobacco identified many components of processes associated with the cell wall, signaling and metabolism as well as novel small secreted peptides. Flowering plants (angiosperms) generate pollen grains that germinate on the stigma and produce tubes to transport their sperm cells cargo deep into the maternal reproductive tissues toward the ovules for a double fertilization process. During their journey, pollen tubes secrete many proteins (secreted proteome or secretome) required, for example, for communication with the maternal reproductive tissues, to build a solid own cell wall that withstands their high turgor pressure while softening simultaneously maternal cell wall tissue. The composition and species specificity or family specificity of the pollen tube secretome is poorly understood. Here, we provide a suitable method to obtain the pollen tube secretome from in vitro grown pollen tubes of the basal angiosperm Amborella trichopoda (Amborella) and the Poaceae model maize. The previously published secretome of tobacco pollen tubes was used as an example of eudicotyledonous plants in this comparative study. The secretome of the three species is each strongly different compared to the respective protein composition of pollen grains and tubes. In Amborella and maize, about 40% proteins are secreted by the conventional "classic" pathway and 30% by unconventional pathways. The latter pathway is expanded in tobacco. Proteins enriched in the secretome are especially involved in functions associated with the cell wall, cell surface, energy and lipid metabolism, proteolysis and redox processes. Expansins, pectin methylesterase inhibitors and RALFs are enriched in maize, while tobacco secretes many proteins involved, for example, in proteolysis and signaling. While the majority of proteins detected in the secretome occur also in pollen grains and pollen tubes, and correlate in the number of mapped peptides with relative gene expression levels, some novel secreted small proteins were identified. Moreover, the identification of secreted proteins containing pro-peptides indicates that these are processed in the apoplast. In conclusion, we provide a proteome resource from three distinct angiosperm clades that can be utilized among others to study the localization, abundance and processing of known secreted proteins and help to identify novel pollen tube secreted proteins for functional studies.
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Affiliation(s)
- María Flores-Tornero
- Cell Biology and Plant Biochemistry, University of Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany
| | - Lele Wang
- Cell Biology and Plant Biochemistry, University of Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany
| | - David Potěšil
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, 62500, Brno, Czech Republic
| | - Said Hafidh
- Laboratory of Pollen Biology, Institute of Experimental Botany ASCR, Rozvojová 263, 165 02, Prague 6, Czech Republic
| | - Frank Vogler
- Cell Biology and Plant Biochemistry, University of Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany
| | - Zbyněk Zdráhal
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, 62500, Brno, Czech Republic
| | - David Honys
- Laboratory of Pollen Biology, Institute of Experimental Botany ASCR, Rozvojová 263, 165 02, Prague 6, Czech Republic
| | - Stefanie Sprunck
- Cell Biology and Plant Biochemistry, University of Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany
| | - Thomas Dresselhaus
- Cell Biology and Plant Biochemistry, University of Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany.
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36
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Liu L, Wang T. Male gametophyte development in flowering plants: A story of quarantine and sacrifice. JOURNAL OF PLANT PHYSIOLOGY 2021; 258-259:153365. [PMID: 33548696 DOI: 10.1016/j.jplph.2021.153365] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2020] [Revised: 01/06/2021] [Accepted: 01/06/2021] [Indexed: 05/19/2023]
Abstract
Over 160 years ago, scientists made the first microscopic observations of angiosperm pollen. Unlike in animals, male meiosis in angiosperms produces a haploid microspore that undergoes one asymmetric division to form a vegetative cell and a generative cell. These two cells have distinct fates: the vegetative cell exits the cell cycle and elongates to form a tip-growing pollen tube; the generative cell divides once more in the pollen grain or within the growing pollen tube to form a pair of sperm cells. The concept that male germ cells are less active than the vegetative cell came from biochemical analyses and pollen structure anatomy early in the last century and is supported by the pollen transcriptome data of the last decade. However, the mechanism of how and when the transcriptional repression in male germ cells occurs is still not fully understood. In this review, we provide a brief account of the cytological and metabolic differentiation between the vegetative cell and male germ cells, with emphasis on the role of temporary callose walls, dynamic nuclear pore density, transcription repression, and histone variants. We further discuss the intercellular movement of small interfering RNA (siRNA) derived from transposable elements (TEs) and reexamine the function of TE expression in male germ cells.
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Affiliation(s)
- Lingtong Liu
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
| | - Tai Wang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; College of Life Science, University of Chinese Academy of Sciences, Beijing 100049, China; Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing 100093, China.
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37
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Huang X, Sun MX. Epigenetic regulation and intercellular communication during male gametophyte development. JOURNAL OF PLANT PHYSIOLOGY 2021; 258-259:153391. [PMID: 33647786 DOI: 10.1016/j.jplph.2021.153391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 02/12/2021] [Indexed: 06/12/2023]
Abstract
The male gametophyte of angiosperms has long been recognized as an ideal system for the study of the molecular mechanisms regulating cell fate determination. Recent findings on histone variants in two cell lineages, vegetative-cell-derived small interfering RNA and transposable element expression provide new power for relevant investigations.
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Affiliation(s)
- Xiaorong Huang
- College of Life Science, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan 430072, China
| | - Meng-Xiang Sun
- College of Life Science, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan 430072, China.
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38
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Stephan OOH. Implications of ionizing radiation on pollen performance in comparison with diverse models of polar cell growth. PLANT, CELL & ENVIRONMENT 2021; 44:665-691. [PMID: 33124689 DOI: 10.1111/pce.13929] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 10/21/2020] [Accepted: 10/22/2020] [Indexed: 06/11/2023]
Abstract
Research concerning the effects of ionizing radiation (IR) on plant systems is essential for numerous aspects of human society, as for instance, in terms of agriculture and plant breeding, but additionally for elucidating consequences of radioactive contamination of the ecosphere. This comprehensive survey analyses effects of x- and γ-irradiation on male gametophytes comprising primarily in vitro but also in vivo data of diverse plant species. The IR-dose range for pollen performance was compiled and 50% inhibition doses (ID50 ) for germination and tube growth were comparatively related to physiological characteristics of the microgametophyte. Factors influencing IR-susceptibility of mature pollen and polarized tube growth were evaluated, such as dose-rate, environmental conditions, or species-related variations. In addition, all available reports suggesting bio-positive IR-effects particularly on pollen performance were examined. Most importantly, for the first time influences of IR specifically on diverse phylogenetic models of polar cell growth were comparatively analysed, and thus demonstrated that the gametophytic system of pollen is extremely resistant to IR, more than plant sporophytes and especially much more than comparable animal cells. Beyond that, this study develops hypotheses regarding a molecular basis for the extreme IR-resistance of the plant microgametophyte and highlights its unique rank among organismal systems.
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Affiliation(s)
- Octavian O H Stephan
- Department of Biology, Friedrich-Alexander University of Erlangen-Nuremberg, Erlangen, Germany
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39
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Moser M, Kirkpatrick A, Groves NR, Meier I. LINC-complex mediated positioning of the vegetative nucleus is involved in calcium and ROS signaling in Arabidopsis pollen tubes. Nucleus 2020; 11:149-163. [PMID: 32631106 PMCID: PMC7529407 DOI: 10.1080/19491034.2020.1783783] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Nuclear movement and positioning play a role in developmental processes throughout life. Nuclear movement and positioning are mediated primarily by linker of nucleoskeleton and cytoskeleton (LINC) complexes. LINC complexes are comprised of the inner nuclear membrane SUN proteins and the outer nuclear membrane (ONM) KASH proteins. In Arabidopsis pollen tubes, the vegetative nucleus (VN) maintains a fixed distance from the pollen tube tip during growth, and the VN precedes the sperm cells (SCs). In pollen tubes of wit12 and wifi, mutants deficient in the ONM component of a plant LINC complex, the SCs precede the VN during pollen tube growth and the fixed VN distance from the tip is lost. Subsequently, pollen tubes frequently fail to burst upon reception. In this study, we sought to determine if the pollen tube reception defect observed in wit12 and wifi is due to decreased sensitivity to reactive oxygen species (ROS). Here, we show that wit12 and wifi are hyposensitive to exogenous H2O2, and that this hyposensitivity is correlated with decreased proximity of the VN to the pollen tube tip. Additionally, we report the first instance of nuclear Ca2+ peaks in growing pollen tubes, which are disrupted in the wit12 mutant. In the wit12 mutant, nuclear Ca2+ peaks are reduced in response to exogenous ROS, but these peaks are not correlated with pollen tube burst. This study finds that VN proximity to the pollen tube tip is required for both response to exogenous ROS, as well as internal nuclear Ca2+ fluctuations.
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Affiliation(s)
- Morgan Moser
- Department of Molecular Genetics, The Ohio State University , Columbus, OH, USA
| | - Andrew Kirkpatrick
- Department of Molecular Genetics, The Ohio State University , Columbus, OH, USA
| | - Norman Reid Groves
- Department of Molecular Genetics, The Ohio State University , Columbus, OH, USA.,Center for Applied Plant Sciences, The Ohio State University , Columbus, OH, USA
| | - Iris Meier
- Department of Molecular Genetics, The Ohio State University , Columbus, OH, USA.,Center for Applied Plant Sciences, The Ohio State University , Columbus, OH, USA.,Center for RNA Biology, The Ohio State University , Columbus, OH, USA
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40
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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.
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Affiliation(s)
| | - Shanjin Huang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
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41
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Zheng X, He L, Liu Y, Mao Y, Wang C, Zhao B, Li Y, He H, Guo S, Zhang L, Schneider H, Tadege M, Chang F, Chen J. A study of male fertility control in Medicago truncatula uncovers an evolutionarily conserved recruitment of two tapetal bHLH subfamilies in plant sexual reproduction. THE NEW PHYTOLOGIST 2020; 228:1115-1133. [PMID: 32594537 DOI: 10.1111/nph.16770] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Accepted: 06/11/2020] [Indexed: 06/11/2023]
Abstract
Male sterility is an important tool for plant breeding and hybrid seed production. Male-sterile mutants are largely due to an abnormal development of either the sporophytic or gametophytic anther tissues. Tapetum, a key sporophytic tissue, provides nutrients for pollen development, and its delayed degeneration induces pollen abortion. Numerous bHLH proteins have been documented to participate in the degeneration of the tapetum in angiosperms, but relatively little attention has been given to the evolution of the involved developmental pathways across the phylogeny of land plants. A combination of cellular, molecular, biochemical and evolutionary analyses was used to investigate the male fertility control in Medicago truncatula. We characterized the male-sterile mutant empty anther1 (ean1) and identified EAN1 as a tapetum-specific bHLH transcription factor necessary for tapetum degeneration. Our study uncovered an evolutionarily conserved recruitment of bHLH subfamily II and III(a + c)1 in the regulation of tapetum degeneration. EAN1 belongs to the subfamily II and specifically forms heterodimers with the subfamily III(a + c)1 members, which suggests a heterodimerization mechanism conserved in angiosperms. Our work suggested that the pathway of two tapetal-bHLH subfamilies is conserved in all land plants, and likely was established before the divergence of the spore-producing land plants.
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Affiliation(s)
- Xiaoling Zheng
- CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, Yunnan, 650223, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Liangliang He
- CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, Yunnan, 650223, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ye Liu
- CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, Yunnan, 650223, China
- School of Life Sciences, University of Science and Technology of China, Hefei, 230026, China
| | - Yawen Mao
- CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, Yunnan, 650223, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Chaoqun Wang
- CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, Yunnan, 650223, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Baolin Zhao
- CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, Yunnan, 650223, China
| | - Youhan Li
- CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, Yunnan, 650223, China
| | - Hua He
- CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, Yunnan, 650223, China
| | - Shiqi Guo
- CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, Yunnan, 650223, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Liangsheng Zhang
- Genomics and Genetic Engineering Laboratory of Ornamental Plants, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, 310058, China
| | - Harald Schneider
- Center for Integrative Conservation, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, 666303, China
| | - Million Tadege
- Department of Plant and Soil Sciences, Institute for Agricultural Biosciences, Oklahoma State University, 3210 Sam Noble Parkway, Ardmore, OK, 73401, USA
| | - Fang Chang
- State Key Laboratory of Genetic Engineering, Ministry of Education Key Laboratory of Biodiversity Sciences and Ecological Engineering and Institute of Biodiversity Sciences, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, 200438, China
| | - Jianghua Chen
- CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, Yunnan, 650223, China
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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.
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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
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43
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Borghi M, Fernie AR. Outstanding questions in flower metabolism. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 103:1275-1288. [PMID: 32410253 DOI: 10.1111/tpj.14814] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 04/29/2020] [Accepted: 05/05/2020] [Indexed: 06/11/2023]
Abstract
The great diversity of flowers, their color, odor, taste, and shape, is mostly a result of the metabolic processes that occur in this reproductive organ when the flower and its tissues develop, grow, and finally die. Some of these metabolites serve to advertise flowers to animal pollinators, other confer protection towards abiotic stresses, and a large proportion of the molecules of the central metabolic pathways have bioenergetic and signaling functions that support growth and the transition to fruits and seeds. Although recent studies have advanced our general understanding of flower metabolism, several questions still await an answer. Here, we have compiled a list of open questions on flower metabolism encompassing molecular aspects, as well as topics of relevance for agriculture and the ecosystem. These questions include the study of flower metabolism through development, the biochemistry of nectar and its relevance to promoting plant-pollinator interaction, recycling of metabolic resources after flowers whiter and die, as well as the manipulation of flower metabolism by pathogens. We hope with this review to stimulate discussion on the topic of flower metabolism and set a reference point to return to in the future when assessing progress in the field.
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Affiliation(s)
- Monica Borghi
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, Potsdam, 14476, Germany
| | - Alisdair R Fernie
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, Potsdam, 14476, Germany
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Adhikari PB, Liu X, Kasahara RD. Fertilization-Defective Gametophytic Mutant Screening: A Novel Approach. FRONTIERS IN PLANT SCIENCE 2020; 11:967. [PMID: 32714355 PMCID: PMC7340155 DOI: 10.3389/fpls.2020.00967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 06/12/2020] [Indexed: 06/11/2023]
Abstract
Gametophytic mutants share very small proportion of the total mutants generated by any mutagenic approach; even rarer are the fertilization-defective gametophytic mutants. They require an efficient and targeted strategy instead of 'brute force' screening approach. The classical gametophyte mutant screening method, mainly based on the segregation distortion, can distinguish gametophytic mutants from the others. However, the mutants pooled after the screening constitute both fertilization-defective and developmental-defective gametophytic mutants. Until recently, there has not been any straightforward way to screen the former from the latter. Additionally, most of the mutations affecting both gametes are lost during the screening process. The novel gametophyte screening approach tends to circumvent those shortcomings. This review discusses on the classical approach of gametophytic mutant screening and focuses on the novel approach on distinguishing fertilization-/developmental-defective gametophytic mutants (both male and female). It offers an empirical basis of screening such mutants by taking in the consideration of earlier studies on fertilization failure, initiation of seed coat formation, and fertilization recovery system in plants.
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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
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AtSK11 and AtSK12 Mediate the Mild Osmotic Stress-Induced Root Growth Response in Arabidopsis. Int J Mol Sci 2020; 21:ijms21113991. [PMID: 32498390 PMCID: PMC7312642 DOI: 10.3390/ijms21113991] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 05/26/2020] [Accepted: 05/31/2020] [Indexed: 11/30/2022] Open
Abstract
Although most osmotic stresses are harmful to plant growth and development, certain drought- or polyethylene glycol (PEG)-induced mild osmotic stresses promote plant root growth. The underlying regulatory mechanisms of this response remain elusive. Here, we report that the GLYCOGEN SYNTHASE KINASE 3 (GSK3) genes ARABIDOPSIS THALIANA SHAGGY-RELATED KINASE 11 (AtSK11) (AT5G26751) and AtSK12 (AT3G05840) are involved in the mild osmotic stress (−0.4 MPa) response in Arabidopsis thaliana. When grown on plant medium infused with different concentrations of PEG to mimic osmotic stress, both wild-type (WT) and atsk11atsk12 plants showed stimulated root growth under mild osmotic stress (−0.4 MPa) but repressed root growth under relatively strong osmotic stress (−0.5, −0.6, −0.7 MPa) as compared to the mock condition (−0.25 MPa). The root growth stimulation of atsk11atsk12 was more sensitive to −0.4 MPa treatment than was that of WT, indicating that AtSK11 and AtSK12 inhibit the mild stress-induced root growth response. RNA-seq analysis of WT and atsk11atsk12 plants under three water potentials (−0.25 MPa, −0.4 MPa, −0.6 MPa) revealed 10 differentially expressed candidate genes mainly involved in cell wall homeostasis, which were regulated by AtSK11 and AtSK12 to regulate root growth in response to the mild stress condition (−0.4 MPa). Promoter motif and transcription factor binding analyses suggested that the basic helix-loop-helix (bHLH) transcription factor bHLH69/LJRHL1-LIKE 2 (LRL2) may directly regulate the expression of most −0.4 MPa-responsive genes. These findings indicate that mild osmotic stress (−0.4 MPa) promotes plant growth and that the GSK3 family kinase genes AtSK11 and AtSK12 play a negative role in the induction of root growth in response to mild osmotic stress.
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46
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Reimann R, Kah D, Mark C, Dettmer J, Reimann TM, Gerum RC, Geitmann A, Fabry B, Dietrich P, Kost B. Durotropic Growth of Pollen Tubes. PLANT PHYSIOLOGY 2020; 183:558-569. [PMID: 32241878 PMCID: PMC7271775 DOI: 10.1104/pp.19.01505] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 03/23/2020] [Indexed: 05/06/2023]
Abstract
To reach the female gametophyte, growing pollen tubes must penetrate different tissues within the pistil, the female reproductive organ of a flower. Past research has identified various chemotropic cues that guide pollen tubes through the transmitting tract of the pistil, which represents the longest segment of its growth path. In addition, physical mechanisms also play a role in pollen tube guidance; however, these processes remain poorly understood. Here we show that pollen tubes from plants with solid transmitting tracts actively respond to the stiffness of the environment. We found that pollen tubes from Nicotiana tabacum and other plant species with a solid or semisolid transmitting tract increase their growth rate in response to an increasing matrix stiffness. By contrast, pollen tubes from Lilium longiflorum and other plant species with a hollow transmitting tract decrease their growth rate with increasing matrix stiffness, even though the forces needed to maintain a constant growth rate remain far below the maximum penetration force these pollen tubes are able to generate. Moreover, when confronted with a transition from a softer to a stiffer matrix, pollen tubes from N. tabacum display a greater ability to penetrate into a stiffer matrix compared with pollen tubes from L. longiflorum, even though the maximum force generated by pollen tubes from N. tabacum (11 µN) is smaller than the maximum force generated by pollen tubes from L. longiflorum (36 µN). These findings demonstrate a mechano-sensitive growth behavior, termed here durotropic growth, that is only expressed in pollen tubes from plants with a solid or semisolid transmitting tract and thus may contribute to an effective pollen tube guidance within the pistil.
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Affiliation(s)
- Ronny Reimann
- Cell Biology, Department of Biology, University of Erlangen-Nuremberg, 91052 Erlangen, Germany
- Molecular Plant Physiology, Department of Biology, University of Erlangen-Nuremberg, 91052 Erlangen, Germany
| | - Delf Kah
- Biophysics, Department of Physics, University of Erlangen-Nuremberg, 91052 Erlangen, Germany
| | - Christoph Mark
- Biophysics, Department of Physics, University of Erlangen-Nuremberg, 91052 Erlangen, Germany
| | - Jan Dettmer
- Cell Biology, Department of Biology, University of Erlangen-Nuremberg, 91052 Erlangen, Germany
| | - Theresa M Reimann
- Cell Biology, Department of Biology, University of Erlangen-Nuremberg, 91052 Erlangen, Germany
| | - Richard C Gerum
- Biophysics, Department of Physics, University of Erlangen-Nuremberg, 91052 Erlangen, Germany
| | - Anja Geitmann
- Department of Plant Science, McGill University, Macdonald Campus, Ste-Anne-de-Bellevue, Québec H9X 3V9, Canada
| | - Ben Fabry
- Biophysics, Department of Physics, University of Erlangen-Nuremberg, 91052 Erlangen, Germany
| | - Petra Dietrich
- Molecular Plant Physiology, Department of Biology, University of Erlangen-Nuremberg, 91052 Erlangen, Germany
| | - Benedikt Kost
- Cell Biology, Department of Biology, University of Erlangen-Nuremberg, 91052 Erlangen, Germany
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Yang F, Wang T, Liu L. Pollen germination is impaired by disruption of a Shaker K + channel OsAKT1.2 in rice. JOURNAL OF PLANT PHYSIOLOGY 2020; 248:153140. [PMID: 32114250 DOI: 10.1016/j.jplph.2020.153140] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 02/10/2020] [Accepted: 02/11/2020] [Indexed: 06/10/2023]
Abstract
Potassium homeostasis is essential for pollen development and pollen-pistil interactions during the sexual reproduction of flowering plants. Here, we described the role of a Shaker K+ channel, OsAKT1.2, in rice pollen germination and growth. OsAKT1.2 is specifically expressed in the tricellular pollen, mature pollen grains and growing pollen tubes. Using CRISPR gene editing, we found that knockout lines did not differ from wildtype in vegetative growth, but showed decreased pollen germination rate both in the germination medium and in vivo. OsAKT1.2-GFP fusion protein was localized in the plasma membrane and enriched at the pollen tube tip. OsAKT1.2 could complement the yeast strain which is deficient in K+ intake. These findings suggest that OsAKT1.2 is associated with pollen germination and tube elongation in rice.
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Affiliation(s)
- Fan Yang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; College of Life Science, University of Chinese Academy of Sciences, Beijing 100093, China.
| | - Tai Wang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; College of Life Science, University of Chinese Academy of Sciences, Beijing 100093, China; Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing 100093, China.
| | - Lingtong Liu
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
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48
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Sprunck S. Twice the fun, double the trouble: gamete interactions in flowering plants. CURRENT OPINION IN PLANT BIOLOGY 2020; 53:106-116. [PMID: 31841779 DOI: 10.1016/j.pbi.2019.11.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 11/14/2019] [Accepted: 11/17/2019] [Indexed: 05/13/2023]
Abstract
During sexual reproduction two gametes of opposite sex unite to produce a zygote. Gamete fusion is a highly controlled process and it has become evident that, across species, common concepts apply to this ancient and fundamental event. Sexual reproduction in flowering plants is even more complex in that two sperm cells fertilize two female reproductive cells (egg and central cell) in a process called double fertilization. Due to the coordinated developmental progression and mutual dependency of the two fertilization products (embryo and endosperm), the success and timing of the two fusion events substantially affects seed set. So far, four proteins are known to act on the surfaces of Arabidopsis gametes to accomplish double fertilization. The molecular and evolutionary characteristics of these players prove that flowering plants integrate plant-specific and widely conserved mechanisms to accomplish the timely fusion of each sperm cell with one female reproductive cell.
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Affiliation(s)
- Stefanie Sprunck
- Cell Biology and Plant Biochemistry, University of Regensburg, Universitätsstr. 31, 93053 Regensburg, Germany.
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49
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Oh SA, Hoai TNT, Park HJ, Zhao M, Twell D, Honys D, Park SK. MYB81, a microspore-specific GAMYB transcription factor, promotes pollen mitosis I and cell lineage formation in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 101:590-603. [PMID: 31610057 DOI: 10.1111/tpj.14564] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 09/10/2019] [Accepted: 09/20/2019] [Indexed: 06/10/2023]
Abstract
Sexual reproduction in flowering plants relies on the production of haploid gametophytes that consist of germline and supporting cells. During male gametophyte development, the asymmetric mitotic division of an undetermined unicellular microspore segregates these two cell lineages. To explore genetic regulation underlying this process, we screened for pollen cell patterning mutants and isolated the heterozygous myb81-1 mutant that sheds ~50% abnormal pollen. Typically, myb81-1 microspores fail to undergo pollen mitosis I (PMI) and arrest at polarized stage with a single central vacuole. Although most myb81-1 microspores degenerate without division, a small fraction divides at later stages and fails to acquire correct cell fates. The myb81-1 allele is transmitted normally through the female, but rarely through pollen. We show that myb81-1 phenotypes result from impaired function of the GAMYB transcription factor MYB81. The MYB81 promoter shows microspore-specific activity and a MYB81-RFP fusion protein is only expressed in a narrow window prior to PMI. Ectopic expression of MYB81 driven by various promoters can severely impair vegetative or reproductive development, reflecting the strict microspore-specific control of MYB81. Our data demonstrate that MYB81 has a key role in the developmental progression of microspores, enabling formation of the two male cell lineages that are essential for sexual reproduction in Arabidopsis.
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Affiliation(s)
- Sung-Aeong Oh
- School of Applied Biosciences, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Thuong Nguyen Thi Hoai
- School of Applied Biosciences, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Hyo-Jin Park
- School of Applied Biosciences, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Mingmin Zhao
- Department of Genetics and Genome Biology, University of Leicester, University Road, Leicester, LE1 7RH, UK
| | - David Twell
- Department of Genetics and Genome Biology, University of Leicester, University Road, Leicester, LE1 7RH, UK
| | - David Honys
- Laboratory of Pollen Biology, Institute of Experimental Botany of the Czech Academy of Sciences, v.v.i., Prague, Czech Republic
| | - Soon-Ki Park
- School of Applied Biosciences, Kyungpook National University, Daegu, 41566, Republic of Korea
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50
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Zhong S, Wang Z, Qu LJ. Obtaining Mutant Pollen for Phenotypic Analysis and Pollen Tube Dual Staining. Methods Mol Biol 2020; 2160:181-190. [PMID: 32529436 DOI: 10.1007/978-1-0716-0672-8_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Mutant phenotype observation is the most useful and important method to study which biological process a gene-of-interest is involved in. In flowering plants, excessive pollen grains land and germinate on the stigma, then pollen tubes grow through the transmitting tract to reach the ovules, eventually enter the micropyle to complete double fertilization. First, for mutants whose homozygotes could not be obtained due to pollen tube defects, it is difficult to observe the defect phenotype since the pollen grains of different genotypes are mixed together. Here, we provide a detailed protocol to pick out mutant pollen grains from the heterozygous mutant plants in Arabidopsis thaliana. By using this method, we could obtain sufficient mutant pollen grains for phenotypic analysis. Second, it is difficult to compare the pollen/pollen tube behavior of two different genotypes/species in vivo in a same pistil. Here, we develop a new dual staining method which combines GUS staining with aniline blue staining. By using this method, we can analyze the competence of the two different pollen tubes in the same pistil.
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Affiliation(s)
- Sheng Zhong
- State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing, People's Republic of China
| | - Zhijuan Wang
- State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing, People's Republic of China
| | - Li-Jia Qu
- State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences at College of Life Sciences, Peking University, Beijing, People's Republic of China. .,National Plant Gene Research Center, Peking University, Beijing, People's Republic of China.
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