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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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Tang C, Wang P, Zhu X, Qi K, Xie Z, Zhang H, Li X, Gao H, Gu T, Gu C, Li S, de Graaf BHJ, Zhang S, Wu J. Acetylation of inorganic pyrophosphatase by S-RNase signaling induces pollen tube tip swelling by repressing pectin methylesterase. THE PLANT CELL 2023; 35:3544-3565. [PMID: 37306489 PMCID: PMC10473231 DOI: 10.1093/plcell/koad162] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 05/19/2023] [Accepted: 06/01/2023] [Indexed: 06/13/2023]
Abstract
Self-incompatibility (SI) is a widespread genetically determined system in flowering plants that prevents self-fertilization to promote gene flow and limit inbreeding. S-RNase-based SI is characterized by the arrest of pollen tube growth through the pistil. Arrested pollen tubes show disrupted polarized growth and swollen tips, but the underlying molecular mechanism is largely unknown. Here, we demonstrate that the swelling at the tips of incompatible pollen tubes in pear (Pyrus bretschneideri [Pbr]) is mediated by the SI-induced acetylation of the soluble inorganic pyrophosphatase (PPA) PbrPPA5. Acetylation at Lys-42 of PbrPPA5 by the acetyltransferase GCN5-related N-acetyltransferase 1 (GNAT1) drives accumulation of PbrPPA5 in the nucleus, where it binds to the transcription factor PbrbZIP77, forming a transcriptional repression complex that inhibits the expression of the pectin methylesterase (PME) gene PbrPME44. The function of PbrPPA5 as a transcriptional repressor does not require its PPA activity. Downregulating PbrPME44 resulted in increased levels of methyl-esterified pectins in growing pollen tubes, leading to swelling at their tips. These observations suggest a mechanism for PbrPPA5-driven swelling at the tips of pollen tubes during the SI response. The targets of PbrPPA5 include genes encoding cell wall-modifying enzymes, which are essential for building a continuous sustainable mechanical structure for pollen tube growth.
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Affiliation(s)
- Chao Tang
- State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Sanya Institute of Nanjing Agricultural University, Nanjing Agricultural University, Nanjing 210095, China
- Jiangsu Engineering Research Center for Pear, Nanjing Agricultural University, Nanjing 210014, China
| | - Peng Wang
- State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Sanya Institute of Nanjing Agricultural University, Nanjing Agricultural University, Nanjing 210095, China
- Jiangsu Engineering Research Center for Pear, Nanjing Agricultural University, Nanjing 210014, China
| | - Xiaoxuan Zhu
- State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Sanya Institute of Nanjing Agricultural University, Nanjing Agricultural University, Nanjing 210095, China
- Jiangsu Engineering Research Center for Pear, Nanjing Agricultural University, Nanjing 210014, China
| | - Kaijie Qi
- State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Sanya Institute of Nanjing Agricultural University, Nanjing Agricultural University, Nanjing 210095, China
- Jiangsu Engineering Research Center for Pear, Nanjing Agricultural University, Nanjing 210014, China
| | - Zhihua Xie
- State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Sanya Institute of Nanjing Agricultural University, Nanjing Agricultural University, Nanjing 210095, China
- Jiangsu Engineering Research Center for Pear, Nanjing Agricultural University, Nanjing 210014, China
| | - Hao Zhang
- State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Sanya Institute of Nanjing Agricultural University, Nanjing Agricultural University, Nanjing 210095, China
- Jiangsu Engineering Research Center for Pear, Nanjing Agricultural University, Nanjing 210014, China
| | - Xiaoqiang Li
- State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Sanya Institute of Nanjing Agricultural University, Nanjing Agricultural University, Nanjing 210095, China
- Jiangsu Engineering Research Center for Pear, Nanjing Agricultural University, Nanjing 210014, China
| | - Hongru Gao
- State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Sanya Institute of Nanjing Agricultural University, Nanjing Agricultural University, Nanjing 210095, China
- Jiangsu Engineering Research Center for Pear, Nanjing Agricultural University, Nanjing 210014, China
| | - Tingting Gu
- State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Sanya Institute of Nanjing Agricultural University, Nanjing Agricultural University, Nanjing 210095, China
| | - Chao Gu
- State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Sanya Institute of Nanjing Agricultural University, Nanjing Agricultural University, Nanjing 210095, China
- Jiangsu Engineering Research Center for Pear, Nanjing Agricultural University, Nanjing 210014, China
| | - Shan Li
- State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Sanya Institute of Nanjing Agricultural University, Nanjing Agricultural University, Nanjing 210095, China
| | | | - Shaoling Zhang
- State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Sanya Institute of Nanjing Agricultural University, Nanjing Agricultural University, Nanjing 210095, China
- Jiangsu Engineering Research Center for Pear, Nanjing Agricultural University, Nanjing 210014, China
| | - Juyou Wu
- State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Sanya Institute of Nanjing Agricultural University, Nanjing Agricultural University, Nanjing 210095, China
- Jiangsu Engineering Research Center for Pear, Nanjing Agricultural University, Nanjing 210014, China
- Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
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Sugi N, Izumi R, Tomomi S, Susaki D, Kinoshita T, Maruyama D. Removal of the endoplasma membrane upon sperm cell activation after pollen tube discharge. FRONTIERS IN PLANT SCIENCE 2023; 14:1116289. [PMID: 36778680 PMCID: PMC9909283 DOI: 10.3389/fpls.2023.1116289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 01/17/2023] [Indexed: 06/18/2023]
Abstract
In pollen and pollen tubes, immotile sperm cells are enclosed by an inner vegetative plasma membrane (IVPM), a single endomembrane originating from the vegetative-cell plasma membrane. It is widely believed that sperm cells must be removed from the IVPM prior to gamete associations and fusions; however, details of the timing and morphological changes upon IVPM dissociation remain elusive. Here, we report a rapid IVPM breakdown immediately before double fertilization in Arabidopsis thaliana. The IVPM was stably observed in coiling pollen tubes when pollen tube discharge was prevented using lorelei mutant ovules. In contrast, a semi-in vivo fertilization assay in wild-type ovules demonstrated fragmented IVPM around sperm nuclei 1 min after pollen tube discharge. These observations revealed the dynamic alteration of released sperm cells and provided new insights into double fertilization in flowering plants. With a summary of recent findings on IVPM lipid composition, we discussed the possible physiological signals controlling IVPM breakdown.
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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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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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Wang H, Cao S, Li T, Zhang L, Yao J, Xia X, Zhang R. Classification and expression analysis of cucumber ( Cucumis sativus L.) callose synthase ( CalS) family genes and localization of CsCalS4, a protein involved in pollen development. BIOTECHNOL BIOTEC EQ 2021. [DOI: 10.1080/13102818.2022.2038670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Affiliation(s)
- Hongyun Wang
- Institute of Vegetables and Flowers Research, Yantai Agricultural Science Academy of Shandong Province, Yantai, China
| | - Shoujun Cao
- Institute of Vegetables and Flowers Research, Yantai Agricultural Science Academy of Shandong Province, Yantai, China
| | - Tao Li
- Institute of Vegetables and Flowers Research, Yantai Agricultural Science Academy of Shandong Province, Yantai, China
| | - Lili Zhang
- Institute of Vegetables and Flowers Research, Yantai Agricultural Science Academy of Shandong Province, Yantai, China
| | - Jiangang Yao
- Institute of Vegetables and Flowers Research, Yantai Agricultural Science Academy of Shandong Province, Yantai, China
| | - Xiubo Xia
- Institute of Vegetables and Flowers Research, Yantai Agricultural Science Academy of Shandong Province, Yantai, China
| | - Ruiqing Zhang
- Institute of Vegetables and Flowers Research, Yantai Agricultural Science Academy of Shandong Province, Yantai, China
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