1
|
Xiang X, Wan ZY, Zhang S, Feng QN, Li SW, Yin GM, Zhi JY, Liang X, Ma T, Li S, Zhang Y. Arabidopsis class A S-acyl transferases modify the pollen receptors LIP1 and PRK1 to regulate pollen tube guidance. THE PLANT CELL 2024; 36:3419-3434. [PMID: 38635962 PMCID: PMC11371148 DOI: 10.1093/plcell/koae109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 03/08/2024] [Accepted: 03/14/2024] [Indexed: 04/20/2024]
Abstract
Protein S-acylation catalyzed by protein S-acyl transferases (PATs) is a reversible lipid modification regulating protein targeting, stability, and interaction profiles. PATs are encoded by large gene families in plants, and many proteins including receptor-like cytoplasmic kinases (RLCKs) and receptor-like kinases (RLKs) are subject to S-acylation. However, few PATs have been assigned substrates, and few S-acylated proteins have known upstream enzymes. We report that Arabidopsis (Arabidopsis thaliana) class A PATs redundantly mediate pollen tube guidance and participate in the S-acylation of POLLEN RECEPTOR KINASE1 (PRK1) and LOST IN POLLEN TUBE GUIDANCE1 (LIP1), a critical RLK or RLCK for pollen tube guidance, respectively. PAT1, PAT2, PAT3, PAT4, and PAT8, collectively named PENTAPAT for simplicity, are enriched in pollen and show similar subcellular distribution. Functional loss of PENTAPAT reduces seed set due to male gametophytic defects. Specifically, pentapat pollen tubes are compromised in directional growth. We determine that PRK1 and LIP1 interact with PENTAPAT, and their S-acylation is reduced in pentapat pollen. The plasma membrane (PM) association of LIP1 is reduced in pentapat pollen, whereas point mutations reducing PRK1 S-acylation affect its affinity with its interacting proteins. Our results suggest a key role of S-acylation in pollen tube guidance through modulating PM receptor complexes.
Collapse
Affiliation(s)
- Xiaojiao Xiang
- College of Life Sciences, Shandong Agricultural University, Tai’an 271018, China
| | - Zhi-Yuan Wan
- College of Life Sciences, Shandong Agricultural University, Tai’an 271018, China
| | - Shuzhan Zhang
- College of Life Sciences, Shandong Agricultural University, Tai’an 271018, China
| | - Qiang-Nan Feng
- College of Life Sciences, Shandong Agricultural University, Tai’an 271018, China
| | - Shan-Wei Li
- College of Life Sciences, Shandong Agricultural University, Tai’an 271018, China
| | - Gui-Min Yin
- Frontiers Science Center for Cell Responses, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Jing-Yu Zhi
- Frontiers Science Center for Cell Responses, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Xin Liang
- Frontiers Science Center for Cell Responses, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Ting Ma
- College of Life Sciences, Shandong Agricultural University, Tai’an 271018, China
| | - Sha Li
- College of Life Sciences, Shandong Agricultural University, Tai’an 271018, China
| | - Yan Zhang
- College of Life Sciences, Shandong Agricultural University, Tai’an 271018, China
- Frontiers Science Center for Cell Responses, College of Life Sciences, Nankai University, Tianjin 300071, China
| |
Collapse
|
2
|
Denninger P. RHO OF PLANTS signalling and the activating ROP GUANINE NUCLEOTIDE EXCHANGE FACTORS: specificity in cellular signal transduction in plants. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:3685-3699. [PMID: 38683617 PMCID: PMC11194304 DOI: 10.1093/jxb/erae196] [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: 01/16/2024] [Accepted: 04/28/2024] [Indexed: 05/01/2024]
Abstract
Every cell constantly receives signals from its neighbours or the environment. In plants, most signals are perceived by RECEPTOR-LIKE KINASEs (RLKs) and then transmitted into the cell. The molecular switches RHO OF PLANTS (ROP) are critical proteins for polar signal transduction and regulate multiple cell polarity processes downstream of RLKs. Many ROP-regulating proteins and scaffold proteins of the ROP complex are known. However, the spatiotemporal ROP signalling complex composition is not yet understood. Moreover, how specificity is achieved in different ROP signalling pathways within one cell still needs to be determined. This review gives an overview of recent advances in ROP signalling and how specificity by downstream scaffold proteins can be achieved. The composition of the ROP signalling complexes is discussed, focusing on the possibility of the simultaneous presence of ROP activators and inactivators within the same complex to balance ROP activity. Furthermore, this review highlights the function of plant-specific ROP GUANINE NUCLEOTIDE EXCHANGE FACTORS polarizing ROP signalling and defining the specificity of the initiated ROP signalling pathway.
Collapse
Affiliation(s)
- Philipp Denninger
- Plant Systems Biology, School of Life Sciences, Technical University of Munich, Emil-Ramann-Strasse 8, 85354 Freising, Germany
| |
Collapse
|
3
|
Xu X, Xie L, Zhou S, An J, Huang Y, Liu Y, Jin L. Effect of Welding Defects on Fatigue Properties of SWA490BW Steel Cruciform Welded Joints. MATERIALS (BASEL, SWITZERLAND) 2023; 16:4751. [PMID: 37445065 PMCID: PMC10342622 DOI: 10.3390/ma16134751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 06/19/2023] [Accepted: 06/28/2023] [Indexed: 07/15/2023]
Abstract
Welding is prone to several defects. To test the fatigue properties of the welded defective joints of high-speed rail bogies, SMA490BW steel cruciform welded joints were employed with artificial defects treatment. Consequently, fatigue tests were conducted on the specimens. Fatigue fracture morphology was studied via scanning electron microscopy. The ABAQUS (version 2022) finite element software was used to calculate the stress distribution and concentration factor of cruciform welded joints with defects. The results show that the fatigue limits of 1 and 2.4 mm defect specimens were approximately 57.2 and 53.75 Mpa, respectively. Furthermore, the stress concentration factor of no, 1 mm, and 2.4 mm defects were 2.246, 4.441, and 6.684, respectively, indicating that the stress concentration factor of 1 and 2.4 mm defects increased by 98 and 198%, respectively, with respect to the no-defect case.
Collapse
Affiliation(s)
- Xingyuan Xu
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang 110004, China; (X.X.); (L.X.)
| | - Liyang Xie
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang 110004, China; (X.X.); (L.X.)
| | - Song Zhou
- Key Laboratory of Fundamental Science for National Defense of Aeronautical Digital Manufacturing Process, Shenyang Aerospace University, Shenyang 110136, China; (J.A.); (Y.H.)
| | - Jinlan An
- Key Laboratory of Fundamental Science for National Defense of Aeronautical Digital Manufacturing Process, Shenyang Aerospace University, Shenyang 110136, China; (J.A.); (Y.H.)
| | - Yanqing Huang
- Key Laboratory of Fundamental Science for National Defense of Aeronautical Digital Manufacturing Process, Shenyang Aerospace University, Shenyang 110136, China; (J.A.); (Y.H.)
| | - Youcheng Liu
- School of Mechanical and Electrical Engineering, Shenyang Aerospace University, Shenyang 110006, China; (Y.L.); (L.J.)
| | - Lei Jin
- School of Mechanical and Electrical Engineering, Shenyang Aerospace University, Shenyang 110006, China; (Y.L.); (L.J.)
| |
Collapse
|
4
|
Liang S, Hu ML, Lin HC, He HJ, Ning XP, Peng PP, Lu GH, Sun SL, Wang XJ, Wang YQ, Wu H. Transcriptional regulations of pollen tube reception are associated with the fertility of the ginger species Zingiber zerumbet and Zingiber corallinum. FRONTIERS IN PLANT SCIENCE 2023; 14:1099250. [PMID: 37235019 PMCID: PMC10208065 DOI: 10.3389/fpls.2023.1099250] [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: 11/15/2022] [Accepted: 04/17/2023] [Indexed: 05/28/2023]
Abstract
Zingiber zerumbet and Zingiber corallinum are economically valuable species in the genus Zingiber. While Z. corallinum is sexually active, Z. zerumbet adopts clonal propagation, although it has the potential for sexual reproduction. It is unclear so far at which step during the sexual reproduction of Z. zerumbet inhibition occurs, and what are the regulatory mechanisms underlying this inhibition. Here, by comparing with the fertile species Z. corallinum using microscopy-based methods, we show that rare differences were observed in Z. zerumbet up to the point when the pollen tubes invaded the ovules. However, a significantly higher percentage of ovules still contained intact pollen tubes 24 h after pollination, suggesting pollen tube rupture was impaired in this species. Further RNA-seq analysis generated accordant results, showing that the transcription of ANX and FER, as well as genes for the partners in the same complexes (e.g., BUPS and LRE, respectively), and those putative peptide signals (e.g., RALF34), were timely activated in Z. corallinum, which ensured the pollen tubes being able to grow, reorient to ovules, and receipt by embryo sacs. In Z. zerumbet, genes for these complexes were cooperatively suppressed, which would result in the maintenance of PT integrity due to the disruption of RALF34-ANX/BUPS signaling in PT and the failure of PT reception by an active synergid due to the insufficiency of the synergid-harbored FER/LRE complex. Taking the results from the cytological and RNA-seq studies together, a model is proposed to illustrate the possible regulation mechanisms in Z. zerumbet and Z. corallinum, in which the regulations for pollen tube rupture and reception are proposed as the barrier for sexual reproduction in Z. zerumbet.
Collapse
Affiliation(s)
- Shan Liang
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Ming-li Hu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Sciences, South China Agricultural University, Guangzhou, China
- School of Pharmacy, Xianning Medical College, Hubei University of Science and Technology, Xianning, China
| | - Hao-chuan Lin
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Han-jun He
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Sciences, South China Agricultural University, Guangzhou, China
| | - Xi-ping Ning
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Sciences, South China Agricultural University, Guangzhou, China
| | - Pei-pei Peng
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Sciences, South China Agricultural University, Guangzhou, China
| | - Guo-hui Lu
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Shu-lan Sun
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Xiao-jing Wang
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Ying-qiang Wang
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Hong Wu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Sciences, South China Agricultural University, Guangzhou, China
| |
Collapse
|
5
|
Robinson R, Sprott D, Couroux P, Routly E, Labbé N, Xing T, Robert LS. The triticale mature pollen and stigma proteomes - assembling the proteins for a productive encounter. J Proteomics 2023; 278:104867. [PMID: 36870675 DOI: 10.1016/j.jprot.2023.104867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 02/13/2023] [Accepted: 02/20/2023] [Indexed: 03/06/2023]
Abstract
Triticeae crops are major contributors to global food production and ensuring their capacity to reproduce and generate seeds is critical. However, despite their importance our knowledge of the proteins underlying Triticeae reproduction is severely lacking and this is not only true of pollen and stigma development, but also of their pivotal interaction. When the pollen grain and stigma are brought together they have each accumulated the proteins required for their intended meeting and accordingly studying their mature proteomes is bound to reveal proteins involved in their diverse and complex interactions. Using triticale as a Triticeae representative, gel-free shotgun proteomics was used to identify 11,533 and 2977 mature stigma and pollen proteins respectively. These datasets, by far the largest to date, provide unprecedented insights into the proteins participating in Triticeae pollen and stigma development and interactions. The study of the Triticeae stigma has been particularly neglected. To begin filling this knowledge gap, a developmental iTRAQ analysis was performed revealing 647 proteins displaying differential abundance as the stigma matures in preparation for pollination. An in-depth comparison to an equivalent Brassicaceae analysis divulged both conservation and diversification in the makeup and function of proteins involved in the pollen and stigma encounter. SIGNIFICANCE: Successful pollination brings together the mature pollen and stigma thus initiating an intricate series of molecular processes vital to crop reproduction. In the Triticeae crops (e.g. wheat, barley, rye, triticale) there persists a vast deficit in our knowledge of the proteins involved which needs to be addressed if we are to face the many upcoming challenges to crop production such as those associated with climate change. At maturity, both the pollen and stigma have acquired the protein complement necessary for their forthcoming encounter and investigating their proteomes will inevitably provide unprecedented insights into the proteins enabling their interactions. By combining the analysis of the most comprehensive Triticeae pollen and stigma global proteome datasets to date with developmental iTRAQ investigations, proteins implicated in the different phases of pollen-stigma interaction enabling pollen adhesion, recognition, hydration, germination and tube growth, as well as those underlying stigma development were revealed. Extensive comparisons between equivalent Triticeae and Brassiceae datasets highlighted both the conservation of biological processes in line with the shared goal of activating the pollen grain and promoting pollen tube invasion of the pistil to effect fertilization, as well as the significant distinctions in their proteomes consistent with the considerable differences in their biochemistry, physiology and morphology.
Collapse
Affiliation(s)
- Reneé Robinson
- Ottawa Research and Development Centre, 960 Carling Ave., Ottawa, Ontario K1A 0C6, Canada; Carleton University, Department of Biology, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6, Canada
| | - David Sprott
- Ottawa Research and Development Centre, 960 Carling Ave., Ottawa, Ontario K1A 0C6, Canada
| | - Philippe Couroux
- Ottawa Research and Development Centre, 960 Carling Ave., Ottawa, Ontario K1A 0C6, Canada
| | - Elizabeth Routly
- Ottawa Research and Development Centre, 960 Carling Ave., Ottawa, Ontario K1A 0C6, Canada
| | - Natalie Labbé
- Ottawa Research and Development Centre, 960 Carling Ave., Ottawa, Ontario K1A 0C6, Canada
| | - Tim Xing
- Carleton University, Department of Biology, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6, Canada
| | - Laurian S Robert
- Ottawa Research and Development Centre, 960 Carling Ave., Ottawa, Ontario K1A 0C6, Canada.
| |
Collapse
|
6
|
Kou X, He Q, Cao P, Wang P, Zhang S, Wu J, Kou X. Comprehensive genomic analysis of the Rho GTPases regulators in seven Rosaceae species revealed that PbrGDI1 controls pollen tube growth in Pyrus via mediating cellulose deposition. Int J Biol Macromol 2023; 235:123860. [PMID: 36868336 DOI: 10.1016/j.ijbiomac.2023.123860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Revised: 02/17/2023] [Accepted: 02/24/2023] [Indexed: 03/05/2023]
Abstract
The primary regulators of Rho GTPases are GTPase-activating protein (GAP), guanine nucleotide exchange factor (GEF), and GDP dissociation inhibitor (GDI), which function as signaling switches in several physiological processes involved in plant growth and development. This study compared how the Rho GTPase regulators functioned in seven Rosaceae species. Seven Rosaceae species, divided into three subgroups, had a total of 177 regulators of Rho GTPases. According to duplication analysis, the expansion of GEF, GAP, and GDI families was facilitated by whole genome duplication or a dispersed duplication event. The balance of cellulose deposition to control the growth of the pear pollen tube, as demonstrated by the expression profile and antisense oligonucleotide approach. Moreover, protein-protein interactions indicated that PbrGDI1 and PbrROP1 could directly interact, suggesting that PbrGDI1 regulated the growth of the pear pollen tube through PbrROP1 signaling downstream. These results lay the foundations for future functional characterization of the GAP, GEF, and GDI gene families in Pyrus bretschneideri.
Collapse
Affiliation(s)
- Xiaobing Kou
- School of Life Sciences, Nantong University, Nantong 226019, Jiangsu, People's Republic of China.
| | - Qianke He
- Centre of Pear Engineering Technology Research, State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Peng Cao
- Centre of Pear Engineering Technology Research, State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Peng Wang
- Centre of Pear Engineering Technology Research, State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Shaoling Zhang
- Centre of Pear Engineering Technology Research, State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Juyou Wu
- Centre of Pear Engineering Technology Research, State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China.
| | - Xiaobing Kou
- School of Life Sciences, Nantong University, Nantong 226019, Jiangsu, People's Republic of China.
| |
Collapse
|
7
|
Yang Y, Niu Y, Chen T, Zhang H, Zhang J, Qian D, Bi M, Fan Y, An L, Xiang Y. The phospholipid flippase ALA3 regulates pollen tube growth and guidance in Arabidopsis. THE PLANT CELL 2022; 34:3718-3736. [PMID: 35861414 PMCID: PMC9516151 DOI: 10.1093/plcell/koac208] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Accepted: 07/13/2022] [Indexed: 06/15/2023]
Abstract
Pollen tube guidance regulates the growth direction and ovule targeting of pollen tubes in pistils, which is crucial for the completion of sexual reproduction in flowering plants. The Arabidopsis (Arabidopsis thaliana) pollen-specific receptor kinase (PRK) family members PRK3 and PRK6 are specifically tip-localized and essential for pollen tube growth and guidance. However, the mechanisms controlling the polar localization of PRKs at the pollen tube tip are unclear. The Arabidopsis P4-ATPase ALA3 helps establish the polar localization of apical phosphatidylserine (PS) in pollen tubes. Here, we discovered that loss of ALA3 function caused pollen tube defects in growth and ovule targeting and significantly affected the polar localization pattern of PRK3 and PRK6. Both PRK3 and PRK6 contain two polybasic clusters in the intracellular juxtamembrane domain, and they bound to PS in vitro. PRK3 and PRK6 with polybasic cluster mutations showed reduced or abolished binding to PS and altered polar localization patterns, and they failed to effectively complement the pollen tube-related phenotypes of prk mutants. These results suggest that ALA3 influences the precise localization of PRK3, PRK6, and other PRKs by regulating the distribution of PS, which plays a key role in regulating pollen tube growth and guidance.
Collapse
Affiliation(s)
| | | | - Tao Chen
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Hongkai Zhang
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Jingxia Zhang
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Dong Qian
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Mengmeng Bi
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Yuemin Fan
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Lizhe An
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | | |
Collapse
|
8
|
Scheible N, Yoon GM, McCubbin AG. Calmodulin Domain Protein Kinase PiCDPK1 Regulates Pollen Tube Growth Polarity through Interaction with RhoGDI. PLANTS (BASEL, SWITZERLAND) 2022; 11:plants11030254. [PMID: 35161234 PMCID: PMC8838988 DOI: 10.3390/plants11030254] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 01/14/2022] [Accepted: 01/17/2022] [Indexed: 05/14/2023]
Abstract
The pollen-specific calcium-dependent protein kinase PiCDPK1 of Petunia inflata has previously been shown to regulate polarity in tip growth in pollen tubes. Here we report the identification of a Rho Guanine Dissociation Inhibitor (PiRhoGDI1) as a PiCDPK1 interacting protein. We demonstrate that PiRhoGDI1 and PiCDPK1 interact in a yeast 2-hybrid assay, as well as in an in vitro pull-down assay, and that PiRhoGDI1 is phosphorylated by PiCDPK1 in vitro. We further demonstrate the PiRhoGDI1 is capable of rescuing the loss of growth polarity phenotype caused by over-expressing PiCDPK1 in vivo using stable transgenic plants. We confirmed that PiRhoGDI1 interacts with a pollen-expressed ROP GTPase isoform consistent with the established role of RhoGDIs in negatively regulating GTPases through their membrane removal and locking them in an inactive cytosolic complex. ROP is a central regulator of polarity in tip growth, upstream of Ca2+, and PiCDPK1 over-expression has been previously reported to lead to dramatic elevation of cytosolic Ca2+ through a positive feedback loop. The discovery that PiCDPK1 impacts ROP regulation via PiRhoGDI1 suggests that PiCDPK1 acts as RhoGDI displacement factor and leads us to propose a model which we hypothesize regulates the rapid recycling of ROP GTPase at the pollen tube tip.
Collapse
|
9
|
Li H, Hu J, Pang J, Zhao L, Yang B, Kang X, Wang A, Xu T, Yang Z. Rho GTPase ROP1 Interactome Analysis Reveals Novel ROP1-Associated Pathways for Pollen Tube Polar Growth in Arabidopsis. Int J Mol Sci 2020; 21:ijms21197033. [PMID: 32987815 PMCID: PMC7582345 DOI: 10.3390/ijms21197033] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 09/09/2020] [Accepted: 09/10/2020] [Indexed: 12/27/2022] Open
Abstract
ROP (Rho-like GTPases from plants) GTPases are polarly localized key regulators of polar growth in pollen tubes and other cells in plants. However, how ROP GTPases are regulated and how they control polar growth remains to be fully understood. To gain new insights into ROP-dependent mechanisms underlying polar cell growth, we characterized the interactome of ROP1 GTPase that controls Arabidopsis pollen tube (PT) tip growth, an extreme form of polar cell growth. We established an efficient method for culturing Arabidopsis pollen tubes in liquid medium, which was used for immunoprecipitation/mass spectrometry-based identification of ROP1-associated proteins. A total of 654 candidates were isolated from the ROP1 interactome in Arabidopsis pollen tubes, and GO (Gene Ontology) classification and pathway analysis revealed multiple uncharacterized ROP1-dependent processes including translation, cell wall modification, post transcriptional modification, and ion homeostasis, in addition to known ROP1-dependent pathways. The ROP1-interactome data was further supported by the co-expression of the candidate interactors in highly mature pollen with PT germination and growth defects being discovered in 25% (8/32) of the candidate mutant genes. Taken together, our work uncovers valuable information for the identification and functional elucidation of ROP-associated proteins in the regulation of polar growth, and provides a reliable reference to identify critical regulators of polar cell growth in the future.
Collapse
Affiliation(s)
- Hui Li
- CAS Center for Excellence in Molecular Plant Sciences/Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 201602, China; (J.H.); (L.Z.); (B.Y.); (X.K.); (T.X.)
- Center for Plant Cell Biology, Institute of Integrative Genome Biology, and Department of Botany and Plant Sciences, University of California, Riverside, CA 92508, USA;
- Correspondence:
| | - Jinbo Hu
- CAS Center for Excellence in Molecular Plant Sciences/Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 201602, China; (J.H.); (L.Z.); (B.Y.); (X.K.); (T.X.)
- Shanghai Institute of Plant Physiology and Ecology, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jing Pang
- School of Life Sciences, Jiangsu Normal University, Xuzhou 221116, China; (J.P.); (A.W.)
| | - Liangtao Zhao
- CAS Center for Excellence in Molecular Plant Sciences/Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 201602, China; (J.H.); (L.Z.); (B.Y.); (X.K.); (T.X.)
| | - Bing Yang
- CAS Center for Excellence in Molecular Plant Sciences/Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 201602, China; (J.H.); (L.Z.); (B.Y.); (X.K.); (T.X.)
| | - Xinlei Kang
- CAS Center for Excellence in Molecular Plant Sciences/Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 201602, China; (J.H.); (L.Z.); (B.Y.); (X.K.); (T.X.)
| | - Aimin Wang
- School of Life Sciences, Jiangsu Normal University, Xuzhou 221116, China; (J.P.); (A.W.)
| | - Tongda Xu
- CAS Center for Excellence in Molecular Plant Sciences/Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 201602, China; (J.H.); (L.Z.); (B.Y.); (X.K.); (T.X.)
- FAFU-UCR Joint Center for Horticultural Biology and Metabolomics, Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Zhenbiao Yang
- Center for Plant Cell Biology, Institute of Integrative Genome Biology, and Department of Botany and Plant Sciences, University of California, Riverside, CA 92508, USA;
| |
Collapse
|
10
|
Guo J, Yang Z. Exocytosis and endocytosis: coordinating and fine-tuning the polar tip growth domain in pollen tubes. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:2428-2438. [PMID: 32173729 PMCID: PMC7178420 DOI: 10.1093/jxb/eraa134] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Accepted: 03/11/2020] [Indexed: 05/06/2023]
Abstract
Pollen tubes rapidly elongate, penetrate, and navigate through multiple female tissues to reach ovules for sperm delivery by utilizing a specialized form of polar growth known as tip growth. This process requires a battery of cellular activities differentially occurring at the apical growing region of the plasma membrane (PM), such as the differential cellular signaling involving calcium (Ca2+), phospholipids, and ROP-type Rho GTPases, fluctuation of ions and pH, exocytosis and endocytosis, and cell wall construction and remodeling. There is an emerging understanding of how at least some of these activities are coordinated and/or interconnected. The apical active ROP modulates exocytosis to the cell apex for PM and cell wall expansion differentially occurring at the tip. The differentiation of the cell wall involves at least the preferential distribution of deformable pectin polymers to the apex and non-deformable pectin polymers to the shank of pollen tubes, facilitating the apical cell expansion driven by high internal turgor pressure. Recent studies have generated inroads into how the ROP GTPase-based intracellular signaling is coordinated spatiotemporally with the external wall mechanics to maintain the tubular cell shape and how the apical cell wall mechanics are regulated to allow rapid tip growth while maintaining the cell wall integrity under the turgor pressure. Evidence suggests that exocytosis and endocytosis play crucial but distinct roles in this spatiotemporal coordination. In this review, we summarize recent advances in the regulation and coordination of the differential pectin distribution and the apical domain of active ROP by exocytosis and endocytosis in pollen tubes.
Collapse
Affiliation(s)
- Jingzhe Guo
- FAFU-UCR Joint Center for Horticultural Biology and Metabolomics, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
- Department of Botany and Plant Sciences and Institute for Integrative Genome Biology, University of California, Riverside, CA, USA
| | - Zhenbiao Yang
- Department of Botany and Plant Sciences and Institute for Integrative Genome Biology, University of California, Riverside, CA, USA
- Correspondence:
| |
Collapse
|
11
|
Towards an understanding of plant reproductive isolation: uncovering the species-specific signal for pollen tube guidance. SCIENCE CHINA-LIFE SCIENCES 2020; 63:620-622. [PMID: 32140908 DOI: 10.1007/s11427-019-1642-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 02/05/2020] [Indexed: 10/24/2022]
|
12
|
Kim EJ, Park SW, Hong WJ, Silva J, Liang W, Zhang D, Jung KH, Kim YJ. Genome-wide analysis of RopGEF gene family to identify genes contributing to pollen tube growth in rice (Oryza sativa). BMC PLANT BIOLOGY 2020; 20:95. [PMID: 32131749 PMCID: PMC7057574 DOI: 10.1186/s12870-020-2298-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 02/20/2020] [Indexed: 05/05/2023]
Abstract
BACKGROUND In plants, the key roles played by RopGEF-mediated ROP signaling in diverse processes, including polar tip growth, have been identified. Despite their important roles in reproduction, a comprehensive analysis of RopGEF members has not yet been performed in rice (Oryza sativa). To determine whether RopGEF regulators are involved in rice pollen tube growth, we performed genome-wide analysis of this family in rice. RESULTS Phylogenomic and meta-expression analysis of eleven RopGEFs in rice showed that four genes were preferentially expressed in mature pollen. These four genes contain the plant-specific Rop nucleotide exchanger (PRONE) domain and possible phosphorylated residues, suggesting a conserved role in polar tip growth with Arabidopsis thaliana. In subcellular localization analysis of the four RopGEFs through tobacco (Nicotiana benthamiana) infiltration, four proteins were predominantly identified in plasma membrane. Moreover, double mutants of RopGEF2/8 exhibited reduced pollen germination, causing partial male sterility. These genes possess unique cis-acting elements in their promoters compared with the other RopGEF genes. CONCLUSIONS In this study, four RopGEF genes were identified as pollen-specific gene in eleven members of rice, and the expression pattern, promoter analysis, and evolutionary relationship of the RopGEF family were studied compared with Arabidopsis. Our study indicated that four RopGEF genes might function during pollen germination in distinct subcellular localization. Our study could provide valuable information on the functional study of RopGEF in rice.
Collapse
Affiliation(s)
- Eui-Jung Kim
- Graduate School of Biotechnology and Crop Biotech Institute, Kyung Hee University, Yongin, 17104 South Korea
| | - Sung-Wook Park
- Graduate School of Biotechnology and Crop Biotech Institute, Kyung Hee University, Yongin, 17104 South Korea
| | - Woo-Jong Hong
- Graduate School of Biotechnology and Crop Biotech Institute, Kyung Hee University, Yongin, 17104 South Korea
| | - Jeniffer Silva
- Graduate School of Biotechnology and Crop Biotech Institute, Kyung Hee University, Yongin, 17104 South Korea
| | - Wanqi Liang
- Joint International Research Laboratory of Metabolic and Developmental Sciences, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University–University of Adelaide Joint Centre for Agriculture and Health, Shanghai Jiao Tong University, Shanghai, China
| | - Dabing Zhang
- Graduate School of Biotechnology and Crop Biotech Institute, Kyung Hee University, Yongin, 17104 South Korea
- Joint International Research Laboratory of Metabolic and Developmental Sciences, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University–University of Adelaide Joint Centre for Agriculture and Health, Shanghai Jiao Tong University, Shanghai, China
| | - Ki-Hong Jung
- Graduate School of Biotechnology and Crop Biotech Institute, Kyung Hee University, Yongin, 17104 South Korea
| | - Yu-Jin Kim
- Graduate School of Biotechnology and Crop Biotech Institute, Kyung Hee University, Yongin, 17104 South Korea
| |
Collapse
|
13
|
Hu S, Ye H, Cui Y, Jiang L. AtSec62 is critical for plant development and is involved in ER-phagy in Arabidopsis thaliana. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2020; 62:181-200. [PMID: 31483571 PMCID: PMC7028082 DOI: 10.1111/jipb.12872] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 08/31/2019] [Indexed: 05/11/2023]
Abstract
The endoplasmic reticulum (ER) is the major site for protein folding in eukaryotic cells. ER homeostasis is essential for the development of an organism, whereby the unfolded protein response (UPR) within the ER is precisely regulated. ER-phagy is a newly identified selective autophagic pathway for removal of misfolded or unfolded proteins within the ER in mammalian cells. Sec62, a component of the translocon complex, was recently characterized as an ER-phagy receptor during the ER stress recovery phase in mammals. In this study, we demonstrated that the Arabidopsis Sec62 (AtSec62) is required for plant development and might function as an ER-phagy receptor in plants. We showed that AtSec62 is an ER-localized membrane protein with three transmembrane domains (TMDs) with its C-terminus facing to the ER lumen. AtSec62 is required for plant development because atsec62 mutants display impaired vegetative growth, abnormal pollen and decreased fertility. atsec62 mutants are sensitive towards tunicamycin (TM)-induced ER stress, whereas overexpression of AtSec62 subsequently enhances stress tolerance during the ER stress recovery phase. Moreover, YFP-AtSec62 colocalizes with the autophagosome marker mCh-Atg8e in ring-like structures upon ER stress induction. Taken together, these data provide evidence for the pivotal roles of AtSec62 in plant development and ER-phagy.
Collapse
Affiliation(s)
- Shuai Hu
- Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, School of Life SciencesThe Chinese University of Hong KongHong KongChina
| | - Hao Ye
- Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, School of Life SciencesThe Chinese University of Hong KongHong KongChina
| | - Yong Cui
- Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, School of Life SciencesThe Chinese University of Hong KongHong KongChina
| | - Liwen Jiang
- Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, School of Life SciencesThe Chinese University of Hong KongHong KongChina
- CUHK Shenzhen Research InstituteThe Chinese University of Hong KongShenzhen518057China
| |
Collapse
|
14
|
ABNORMAL FLOWER AND GRAIN 1 encodes OsMADS6 and determines palea identity and affects rice grain yield and quality. SCIENCE CHINA-LIFE SCIENCES 2020; 63:228-238. [PMID: 31919631 DOI: 10.1007/s11427-019-1593-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Accepted: 11/28/2019] [Indexed: 12/21/2022]
Abstract
The palea and lemma are floral organ structures unique to grasses; these structures form the hull and directly affect grain size and quality. However, the molecular mechanisms controlling the development of the hull are not well understood. In this study, we characterized the rice (Oryza sativa) abnormal flower and grain1 (afg1) mutant, a new allele of OsMADS6. Similar to previously characterized osmads6 alleles, in the afg1 floret, the palea lost its marginal region and acquired the lemma identity. However, in contrast to other osmads6 alleles, the afg1 mutant showed altered grain size and grain quality, with decreased total starch and amylose contents, and increased protein and soluble sugar contents. The analysis of transcriptional activity suggested that AFG1 is a transcriptional activator and may affect grain size by regulating the expression levels of several genes related to cell expansion and proliferation in the afg1 mutant. These results revealed that AFG1 plays an important role in determining palea identity and affecting grain yield and quality in rice.
Collapse
|
15
|
Guo J, Dong X, Li Y, Wang B. NaCl treatment markedly enhanced pollen viability and pollen preservation time of euhalophyte Suaeda salsa via up regulation of pollen development-related genes. JOURNAL OF PLANT RESEARCH 2020; 133:57-71. [PMID: 31654246 DOI: 10.1007/s10265-019-01148-0] [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: 12/28/2018] [Accepted: 10/02/2019] [Indexed: 05/27/2023]
Abstract
Vegetable growth of halophytes has significantly increased through moderate salinity. However, little is known about the reproductive traits of euhalophytes. Male reproduction is pivotal for fertilization and seed production and sensitive to abiotic stressors. The pollen viability and pollen longevity of Suaeda salsa treated with 0 and 200 mM of NaCl were evaluated. It was revealed that the pollen size of S. salsa treated with NaCl was significantly bigger than that in controls. Furthermore, the pollen viability of S. salsa plants treated with NaCl was also significantly higher than that of control after 8 h of the pollens were collected (from 10 to 27 h). The pollen viability of NaCl-treated plants in the field could be maintained for 8 h (from 07:00 to 15:00) in sunny days, which was 1 h longer than that of control plants (from 07:00 to 14:00). Meanwhile, the pollen preservation time of NaCl-treated plants was 16 h at room temperature, which was 8 h longer than that of control plants. Genes related to pollen development, such as SsPRK3, SsPRK4, and SsLRX, exhibited high expression in the flowers of NaCl-treated plants. This indicated that NaCl markedly improved the pollen viability and preservation time via the increased expression of pollen development-related genes, and this benefits the population establishment of halophytes such as S. salsa in saline regions.
Collapse
Affiliation(s)
- Jianrong Guo
- Shandong Provincial Key Laboratory of Plant Stress, College of Life Sciences, Shandong Normal University, Ji'nan, 250014, Shandong, China
| | - Xinxiu Dong
- Shandong Provincial Key Laboratory of Plant Stress, College of Life Sciences, Shandong Normal University, Ji'nan, 250014, Shandong, China
| | - Ying Li
- Shandong Provincial Key Laboratory of Plant Stress, College of Life Sciences, Shandong Normal University, Ji'nan, 250014, Shandong, China
| | - Baoshan Wang
- Shandong Provincial Key Laboratory of Plant Stress, College of Life Sciences, Shandong Normal University, Ji'nan, 250014, Shandong, China.
| |
Collapse
|
16
|
Three-dimensional reconstruction of Picea wilsonii Mast. pollen grains using automated electron microscopy. SCIENCE CHINA-LIFE SCIENCES 2019; 63:171-179. [PMID: 31625022 DOI: 10.1007/s11427-019-9820-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2019] [Accepted: 08/16/2019] [Indexed: 01/07/2023]
Abstract
Three-dimensional electron microscopy (3D-EM) has attracted considerable attention because of its ability to provide detailed information with respect to developmental analysis. However, large-scale high-resolution 3D reconstruction of biological samples remains challenging. Herein, we present a 3D view of a Picea wilsonii Mast. pollen grain with 100 nm axial and 38.57 nm lateral resolution using AutoCUTS-SEM (automatic collector of ultrathin sections-scanning electron microscopy). We established a library of 3,127 100 nm thick serial sections of pollen grains for preservation and observation, demonstrating that the protocol can be used to analyze large-volume samples. After obtaining the SEM images, we reconstructed an entire pollen grain comprising 734 serial sections. The images produced by 3D reconstruction clearly revealed the main components of the P. wilsonii pollen grain, i.e., two sacci and pollen corpus, tube cell, generative cell, and two degenerated prothallial cells, and their internal organization. In addition, we performed a quantitative analysis of the different pollen grain cells, including sacci, and found that there were 202 connections within a saccus SEM image. Thus, for the first time, this study provided a global 3D view of the entire pollen grain, which will be useful for analyzing pollen development and growth.
Collapse
|
17
|
Zhong S, Qu LJ. Cysteine-rich peptides: signals for pollen tube guidance, species isolation and beyond. SCIENCE CHINA-LIFE SCIENCES 2019; 62:1243-1245. [PMID: 31444684 DOI: 10.1007/s11427-019-9819-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 08/08/2019] [Indexed: 11/30/2022]
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, 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), Beijing, 100101, China.
| |
Collapse
|
18
|
The Rho-family GTPase OsRac1 controls rice grain size and yield by regulating cell division. Proc Natl Acad Sci U S A 2019; 116:16121-16126. [PMID: 31320586 DOI: 10.1073/pnas.1902321116] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Grain size is a key factor for determining grain yield in crops and is a target trait for both domestication and breeding, yet the mechanisms underlying the regulation of grain size are largely unclear. Here we show that the grain size and yield of rice (Oryza sativa) is positively regulated by ROP GTPase (Rho-like GTPase from plants), a versatile molecular switch modulating plant growth, development, and responses to the environment. Overexpression of rice OsRac1ROP not only increases cell numbers, resulting in a larger spikelet hull, but also accelerates grain filling rate, causing greater grain width and weight. As a result, OsRac1 overexpression improves grain yield in O. sativa by nearly 16%. In contrast, down-regulation or deletion of OsRac1 causes the opposite effects. RNA-seq and cell cycle analyses suggest that OsRac1 promotes cell division. Interestingly, OsRac1 interacts with and regulates the phosphorylation level of OsMAPK6, which is known to regulate cell division and grain size in rice. Thus, our findings suggest OsRac1 modulates rice grain size and yield by influencing cell division. This study provides insights into the molecular mechanisms underlying the control of rice grain size and suggests that OsRac1 could serve as a potential target gene for breeding high-yield crops.
Collapse
|
19
|
Diao M, Li X, Huang S. Arabidopsis AIP1-1 regulates the organization of apical actin filaments by promoting their turnover in pollen tubes. SCIENCE CHINA-LIFE SCIENCES 2019; 63:239-250. [PMID: 31240522 DOI: 10.1007/s11427-019-9532-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 04/02/2019] [Indexed: 11/24/2022]
Abstract
Apical actin filaments are highly dynamic structures that are crucial for rapid pollen tube growth, but the mechanisms regulating their dynamics and spatial organization remain incompletely understood. We here identify that AtAIP1-1 is important for regulating the turnover and organization of apical actin filaments in pollen tubes. AtAIP1-1 is distributed uniformly in the pollen tube and loss of function of AtAIP1-1 affects the organization of the actin cytoskeleton in the pollen tube. Specifically, actin filaments became disorganized within the apical region of aip1-1 pollen tubes. Consistent with the role of apical actin filaments in spatially restricting vesicles in pollen tubes, the apical region occupied by vesicles becomes enlarged in aip1-1 pollen tubes compared to WT. Using ADF1 as a representative actin-depolymerizing factor, we demonstrate that AtAIP1-1 enhances ADF1-mediated actin depolymerization and filament severing in vitro, although AtAIP1-1 alone does not have an obvious effect on actin assembly and disassembly. The dynamics of apical actin filaments are reduced in aip1-1 pollen tubes compared to WT. Our study suggests that AtAIP1-1 works together with ADF to act as a module in regulating the dynamics of apical actin filaments to facilitate the construction of the unique "apical actin structure" in the pollen tube.
Collapse
Affiliation(s)
- Min Diao
- Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
- iHuman Institute, Shanghai Tech University, Shanghai, 201210, China
| | - Xin Li
- Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Shanjin Huang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China.
| |
Collapse
|
20
|
Scheible N, McCubbin A. Signaling in Pollen Tube Growth: Beyond the Tip of the Polarity Iceberg. PLANTS (BASEL, SWITZERLAND) 2019; 8:E156. [PMID: 31181594 PMCID: PMC6630365 DOI: 10.3390/plants8060156] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 06/04/2019] [Accepted: 06/06/2019] [Indexed: 12/15/2022]
Abstract
The coordinated growth of pollen tubes through floral tissues to deliver the sperm cells to the egg and facilitate fertilization is a highly regulated process critical to the Angiosperm life cycle. Studies suggest that the concerted action of a variety of signaling pathways underlies the rapid polarized tip growth exhibited by pollen tubes. Ca2+ and small GTPase-mediated pathways have emerged as major players in the regulation of pollen tube growth. Evidence suggests that these two signaling pathways not only integrate with one another but also with a variety of other important signaling events. As we continue to elucidate the mechanisms involved in pollen tube growth, there is a growing importance in taking a holistic approach to studying these pathways in order to truly understand how tip growth in pollen tubes is orchestrated and maintained. This review considers our current state of knowledge of Ca2+-mediated and GTPase signaling pathways in pollen tubes, how they may intersect with one another, and other signaling pathways involved. There will be a particular focus on recent reports that have extended our understanding in these areas.
Collapse
Affiliation(s)
- Nolan Scheible
- School of Biological Sciences, Washington State University, Pullman, WA 99164-4236, USA.
| | - Andrew McCubbin
- School of Biological Sciences, Washington State University, Pullman, WA 99164-4236, USA.
- Center for Reproductive Biology, Pullman, WA, 99164, USA.
| |
Collapse
|
21
|
Xi L, Wu XN, Gilbert M, Schulze WX. Classification and Interactions of LRR Receptors and Co-receptors Within the Arabidopsis Plasma Membrane - An Overview. FRONTIERS IN PLANT SCIENCE 2019; 10:472. [PMID: 31057579 PMCID: PMC6477698 DOI: 10.3389/fpls.2019.00472] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 03/28/2019] [Indexed: 05/18/2023]
Abstract
Receptor kinases (RK) constitute the largest protein kinase family in plants. In particular, members of the leucine-rich repeat-receptor kinases (LRR-RKs) are involved in the perception of various signals at the plasma membrane. Experimental evidence over the past years revealed a conserved activation mechanism through ligand-inducible heterodimer formation: a ligand is recognized by a receptor kinase with a large extracellular domain (ECD). This ligand binding receptor directly interacts with a so-called co-receptor with a small ECD for ligand fixation and kinase activation. A large proportion of LRR-RKs is functionally still uncharacterized and the dynamic complexity of the plasma membrane makes it difficult to precisely define receptor kinase heterodimer pairs and their functions. In this review, we give an overview of the current knowledge of LRR receptor and co-receptor functions. We use ECD lengths to classify the LRR receptor kinase family and describe different interaction properties of ligand-binding receptors and their respective co-receptor from a network perspective.
Collapse
|