1
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Cvrčková F, Ghosh R, Kočová H. Transmembrane formins as active cargoes of membrane trafficking. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:3668-3684. [PMID: 38401146 PMCID: PMC11194305 DOI: 10.1093/jxb/erae078] [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: 12/13/2023] [Accepted: 02/23/2024] [Indexed: 02/26/2024]
Abstract
Formins are a large, evolutionarily old family of cytoskeletal regulators whose roles include actin capping and nucleation, as well as modulation of microtubule dynamics. The plant class I formin clade is characterized by a unique domain organization, as most of its members are transmembrane proteins with possible cell wall-binding motifs exposed to the extracytoplasmic space-a structure that appears to be a synapomorphy of the plant kingdom. While such transmembrane formins are traditionally considered mainly as plasmalemma-localized proteins contributing to the organization of the cell cortex, we review, from a cell biology perspective, the growing evidence that they can also, at least temporarily, reside (and in some cases also function) in endomembranes including secretory and endocytotic pathway compartments, the endoplasmic reticulum, the nuclear envelope, and the tonoplast. Based on this evidence, we propose that class I formins may thus serve as 'active cargoes' of membrane trafficking-membrane-embedded proteins that modulate the fate of endo- or exocytotic compartments while being transported by them.
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Affiliation(s)
- Fatima Cvrčková
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná 5, CZ 128 43 Praha 2, Czechia
| | - Rajdeep Ghosh
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná 5, CZ 128 43 Praha 2, Czechia
| | - Helena Kočová
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná 5, CZ 128 43 Praha 2, Czechia
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2
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Zhong S, Zhao P, Peng X, Li HJ, Duan Q, Cheung AY. From gametes to zygote: Mechanistic advances and emerging possibilities in plant reproduction. PLANT PHYSIOLOGY 2024; 195:4-35. [PMID: 38431529 PMCID: PMC11060694 DOI: 10.1093/plphys/kiae125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 02/13/2024] [Accepted: 02/13/2024] [Indexed: 03/05/2024]
Affiliation(s)
- Sheng Zhong
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, New Cornerstone Science Laboratory, College of Life Sciences, Peking University, Beijing 100871, China
| | - Peng Zhao
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
- Hubei Hongshan Laboratory, Wuhan 430070, China
| | - Xiongbo Peng
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
- Hubei Hongshan Laboratory, Wuhan 430070, China
| | - Hong-Ju Li
- Key Laboratory of Seed Innovation, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Center for Molecular Agrobiology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Qiaohong Duan
- College of Horticulture Science and Engineering, Shandong Agricultural University, Tai’an, Shandong 271018, China
| | - Alice Y Cheung
- Department of Biochemistry and Molecular Biology, Molecular and Cellular Biology Program, Plant Biology Graduate Program, University of Massachusetts, Amherst, MA 01003, USA
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3
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Zhang Z, Zhang Z, Shan M, Amjad Z, Xue J, Zhang Z, Wang J, Guo Y. Genome-Wide Studies of FH Family Members in Soybean ( Glycine max) and Their Responses under Abiotic Stresses. PLANTS (BASEL, SWITZERLAND) 2024; 13:276. [PMID: 38256829 PMCID: PMC10820127 DOI: 10.3390/plants13020276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 01/10/2024] [Accepted: 01/15/2024] [Indexed: 01/24/2024]
Abstract
Formins or formin homology 2 (FH2) proteins, evolutionarily conserved multi-domain proteins in eukaryotes, serve as pivotal actin organizers, orchestrating the structure and dynamics of the actin cytoskeleton. However, a comprehensive investigation into the formin family and their plausible involvement in abiotic stress remains undocumented in soybean (Glycine max). In the current study, 34 soybean FH (GmFH)family members were discerned, their genomic distribution spanning the twenty chromosomes in a non-uniform pattern. Evolutionary analysis of the FH gene family across plant species delineated five discernible groups (Group I to V) and displayed a closer evolutionary relationship within Glycine soja, Glycine max, and Arabidopsis thaliana. Analysis of the gene structure of GmFH unveiled variable sequence lengths and substantial diversity in conserved motifs. Structural prediction in the promoter regions of GmFH gene suggested a large set of cis-acting elements associated with hormone signaling, plant growth and development, and stress responses. The investigation of the syntenic relationship revealed a greater convergence of GmFH genes with dicots, indicating a close evolutionary affinity. Transcriptome data unveiled distinctive expression patterns of several GmFH genes across diverse plant tissues and developmental stages, underscoring a spatiotemporal regulatory framework governing the transcriptional dynamics of GmFH gene. Gene expression and qRT-PCR analysis identified many GmFH genes with a dynamic pattern in response to abiotic stresses, revealing their potential roles in regulating plant stress adaptation. Additionally, protein interaction analysis highlighted an intricate web of interactions among diverse GmFH proteins. These findings collectively underscore a novel biological function of GmFH proteins in facilitating stress adaptation in soybeans.
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Affiliation(s)
- Zhenbiao Zhang
- Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao 266101, China
| | - Zhongqi Zhang
- Heze Academy of Agricultural Sciences, Heze 274000, China
| | - Muhammad Shan
- Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao 266101, China
| | - Zarmeena Amjad
- SINO_PAK Joint Research Laboratory, Institute of Plant Breeding and Biotechnology, MNS University of Agriculture, Multan 60000, Pakistan
| | - Jin Xue
- Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao 266101, China
| | - Zenglin Zhang
- Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao 266101, China
| | - Jie Wang
- Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao 266101, China
| | - Yongfeng Guo
- Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao 266101, China
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4
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Zhang R, Xu Y, Yi R, Shen J, Huang S. Actin cytoskeleton in the control of vesicle transport, cytoplasmic organization, and pollen tube tip growth. PLANT PHYSIOLOGY 2023; 193:9-25. [PMID: 37002825 DOI: 10.1093/plphys/kiad203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 03/08/2023] [Accepted: 03/17/2023] [Indexed: 06/19/2023]
Abstract
Pollen tubes extend rapidly via tip growth. This process depends on a dynamic actin cytoskeleton, which has been implicated in controlling organelle movements, cytoplasmic streaming, vesicle trafficking, and cytoplasm organization in pollen tubes. In this update review, we describe the progress in understanding the organization and regulation of the actin cytoskeleton and the function of the actin cytoskeleton in controlling vesicle traffic and cytoplasmic organization in pollen tubes. We also discuss the interplay between ion gradients and the actin cytoskeleton that regulates the spatial arrangement and dynamics of actin filaments and the organization of the cytoplasm in pollen tubes. Finally, we describe several signaling components that regulate actin dynamics in pollen tubes.
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Affiliation(s)
- Ruihui Zhang
- National Key Laboratory of Crop Genetic Improvement, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Yanan Xu
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Ran Yi
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jiangfeng Shen
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Shanjin Huang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
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5
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Zhou Y, He L, Zhou S, Wu Q, Zhou X, Mao Y, Zhao B, Wang D, Zhao W, Wang R, Hu H, Chen J. Genome-Wide Identification and Expression Analysis of the VILLIN Gene Family in Soybean. PLANTS (BASEL, SWITZERLAND) 2023; 12:plants12112101. [PMID: 37299081 DOI: 10.3390/plants12112101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 05/10/2023] [Accepted: 05/17/2023] [Indexed: 06/12/2023]
Abstract
The VILLIN (VLN) protein is an important regulator of the actin cytoskeleton, which orchestrates many developmental processes and participates in various biotic and abiotic responses in plants. Although the VLN gene family and their potential functions have been analyzed in several plants, knowledge of VLN genes in soybeans and legumes remains rather limited. In this study, a total of 35 VLNs were characterized from soybean and five related legumes. Combining with the VLN sequences from other nine land plants, we categorized the VLN gene family into three groups according to phylogenetic relationships. Further detailed analysis of the soybean VLNs indicated that the ten GmVLNs were distributed on 10 of the 20 chromosomes, and their gene structures and protein motifs showed high group specificities. The expression pattern analysis suggested that most GmVLNs are widely expressed in various tissues, but three members have a very high level in seeds. Moreover, we observed that the cis-elements enriched in the promoters of GmVLNs are mainly related to abiotic stresses, hormone signals, and developmental processes. The largest number of cis-elements were associated with light responses, and two GmVLNs, GmVLN5a, and GmVLN5b were significantly increased under the long light condition. This study not only provides some basic information about the VLN gene family but also provides a good reference for further characterizing the diverse functions of VLN genes in soybeans.
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Affiliation(s)
- Yueqiong Zhou
- CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, CAS Center for Excellence in Molecular Plant Sciences, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming 650223, China
- University of Chinese Academy of Sciences, Beijing 101408, China
| | - Liangliang He
- CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, CAS Center for Excellence in Molecular Plant Sciences, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming 650223, China
- University of Chinese Academy of Sciences, Beijing 101408, China
| | - Shaoli Zhou
- CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, CAS Center for Excellence in Molecular Plant Sciences, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming 650223, China
- University of Chinese Academy of Sciences, Beijing 101408, China
| | - Qing Wu
- CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, CAS Center for Excellence in Molecular Plant Sciences, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming 650223, China
- University of Chinese Academy of Sciences, Beijing 101408, China
| | - Xuan Zhou
- CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, CAS Center for Excellence in Molecular Plant Sciences, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming 650223, China
- University of Chinese Academy of Sciences, Beijing 101408, China
| | - Yawen Mao
- CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, CAS Center for Excellence in Molecular Plant Sciences, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming 650223, China
- University of Chinese Academy of Sciences, Beijing 101408, China
| | - Baolin Zhao
- CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, CAS Center for Excellence in Molecular Plant Sciences, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming 650223, China
- University of Chinese Academy of Sciences, Beijing 101408, China
| | - Dongfa Wang
- CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, CAS Center for Excellence in Molecular Plant Sciences, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming 650223, China
- College of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China
| | - Weiyue Zhao
- CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, CAS Center for Excellence in Molecular Plant Sciences, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming 650223, China
- University of Chinese Academy of Sciences, Beijing 101408, China
| | - Ruoruo Wang
- CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, CAS Center for Excellence in Molecular Plant Sciences, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming 650223, China
- Guizhou Institute of Biotechnology, Guizhou Academy of Agricultural Sciences, Guiyang 550006, China
| | - Huabin Hu
- CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, CAS Center for Excellence in Molecular Plant Sciences, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming 650223, China
- University of Chinese Academy of Sciences, Beijing 101408, China
| | - Jianghua Chen
- CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, CAS Center for Excellence in Molecular Plant Sciences, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming 650223, China
- University of Chinese Academy of Sciences, Beijing 101408, China
- College of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China
- Institute of Biodiversity, School of Ecology and Environmental Science, Yunnan University, Kunming 650106, China
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6
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Zhang Y, Dong G, Wu L, Wang X, Chen F, Xiong E, Xiong G, Zhou Y, Kong Z, Fu Y, Zeng D, Ma D, Qian Q, Yu Y. Formin protein DRT1 affects gross morphology and chloroplast relocation in rice. PLANT PHYSIOLOGY 2023; 191:280-298. [PMID: 36102807 PMCID: PMC9806613 DOI: 10.1093/plphys/kiac427] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 08/21/2022] [Indexed: 06/15/2023]
Abstract
Plant height and tiller number are two major factors determining plant architecture and yield. However, in rice (Oryza sativa), the regulatory mechanism of plant architecture remains to be elucidated. Here, we reported a recessive rice mutant presenting dwarf and reduced tillering phenotypes (drt1). Map-based cloning revealed that the phenotypes are caused by a single point mutation in DRT1, which encodes the Class I formin protein O. sativa formin homolog 13 (OsFH13), binds with F-actin, and promotes actin polymerization for microfilament organization. DRT1 protein localized on the plasma membrane (PM) and chloroplast (CP) outer envelope. DRT1 interacted with rice phototropin 2 (OsPHOT2), and the interaction was interrupted in drt1. Upon blue light stimulus, PM localized DRT1 and OsPHOT2 were translocated onto the CP membrane. Moreover, deficiency of DRT1 reduced OsPHOT2 internalization and OsPHOT2-mediated CP relocation. Our study suggests that rice formin protein DRT1/OsFH13 is necessary for plant morphology and CP relocation by modulating the actin-associated cytoskeleton network.
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Affiliation(s)
- Yanli Zhang
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 310036, China
- Rice Research Institute, Shenyang Agricultural University, Shenyang, 110866, China
| | - Guojun Dong
- State Key Laboratory for Rice Biology, China National Rice Research Institute, Hangzhou, 310006, China
| | - Limin Wu
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 310036, China
| | - Xuewen Wang
- Institute of Plant Breeding, Genetics, and Genomics, University of Georgia, Athens, Georgia, 30601, USA
| | - Fei Chen
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 310036, China
| | - Erhui Xiong
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 310036, China
| | - Guosheng Xiong
- Institute of Agricultural Genomics, Chinese Academy of Agricultural Sciences, Shenzhen, 100018, China
| | - Yihua Zhou
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Zhaosheng Kong
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Ying Fu
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Dali Zeng
- State Key Laboratory for Rice Biology, China National Rice Research Institute, Hangzhou, 310006, China
| | - Dianrong Ma
- Rice Research Institute, Shenyang Agricultural University, Shenyang, 110866, China
| | - Qian Qian
- State Key Laboratory for Rice Biology, China National Rice Research Institute, Hangzhou, 310006, China
| | - Yanchun Yu
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 310036, China
- Zhejiang Provincial Key Laboratory for Genetic Improvement and Quality Control of Medicinal Plants, Hangzhou Normal University, Hangzhou, 310036, China
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7
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Zhang Y, An B, Wang W, Zhang B, He C, Luo H, Wang Q. Actin-bundling protein fimbrin regulates pathogenicity via organizing F-actin dynamics during appressorium development in Colletotrichum gloeosporioides. MOLECULAR PLANT PATHOLOGY 2022; 23:1472-1486. [PMID: 35791045 PMCID: PMC9452767 DOI: 10.1111/mpp.13242] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 06/12/2022] [Accepted: 06/14/2022] [Indexed: 06/15/2023]
Abstract
Anthracnose caused by Colletotrichum gloeosporioides leads to serious economic loss to rubber tree yield and other tropical crops. The appressorium, a specialized dome-shaped infection structure, plays a crucial role in the pathogenesis of C. gloeosporioides. However, the mechanism of how actin cytoskeleton dynamics regulate appressorium formation and penetration remains poorly defined in C. gloeosporioides. In this study, an actin cross-linking protein fimbrin homologue (CgFim1) was identified in C. gloeosporioides, and the knockout of CgFim1 led to impairment in vegetative growth, conidiation, and pathogenicity. We then investigated the roles of CgFim1 in the dynamic organization of the actin cytoskeleton. We observed that actin patches and cables localized at the apical and subapical regions of the hyphal tip, and showed a disc-to-ring dynamic around the pore during appressorium development. CgFim1 showed a similar distribution pattern to the actin cytoskeleton. Moreover, knockout of CgFim1 affected the polarity of the actin cytoskeleton in the hyphal tip and disrupted the actin dynamics and ring structure formation in the appressorium, which prevented polar growth and appressorium development. The CgFim1 mutant also interfered with the septin structure formation. This caused defects in pore wall overlay formation, pore contraction, and the extension of the penetration peg. These results reveal the mechanism by which CgFim1 regulates the growth and pathogenicity of C. gloeosporioides by organizing the actin cytoskeleton.
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Affiliation(s)
- Yi Zhang
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresource, Key Laboratory of Biotechnology of Salt Tolerant Crops of Hainan ProvinceCollege of Tropical Crops, Hainan UniversityHaikouChina
- Sanya Nanfan Research Institute of Hainan University, Hainan Yazhou Bay Seed LaboratorySanyaChina
| | - Bang An
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresource, Key Laboratory of Biotechnology of Salt Tolerant Crops of Hainan ProvinceCollege of Tropical Crops, Hainan UniversityHaikouChina
- Sanya Nanfan Research Institute of Hainan University, Hainan Yazhou Bay Seed LaboratorySanyaChina
| | - Wenfeng Wang
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresource, Key Laboratory of Biotechnology of Salt Tolerant Crops of Hainan ProvinceCollege of Tropical Crops, Hainan UniversityHaikouChina
| | - Bei Zhang
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresource, Key Laboratory of Biotechnology of Salt Tolerant Crops of Hainan ProvinceCollege of Tropical Crops, Hainan UniversityHaikouChina
- Sanya Nanfan Research Institute of Hainan University, Hainan Yazhou Bay Seed LaboratorySanyaChina
| | - Chaozu He
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresource, Key Laboratory of Biotechnology of Salt Tolerant Crops of Hainan ProvinceCollege of Tropical Crops, Hainan UniversityHaikouChina
- Sanya Nanfan Research Institute of Hainan University, Hainan Yazhou Bay Seed LaboratorySanyaChina
| | - Hongli Luo
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresource, Key Laboratory of Biotechnology of Salt Tolerant Crops of Hainan ProvinceCollege of Tropical Crops, Hainan UniversityHaikouChina
- Sanya Nanfan Research Institute of Hainan University, Hainan Yazhou Bay Seed LaboratorySanyaChina
| | - Qiannan Wang
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresource, Key Laboratory of Biotechnology of Salt Tolerant Crops of Hainan ProvinceCollege of Tropical Crops, Hainan UniversityHaikouChina
- Sanya Nanfan Research Institute of Hainan University, Hainan Yazhou Bay Seed LaboratorySanyaChina
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8
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Zhang Z, Liu Y, Yuan Q, Xiong C, Xu H, Hu B, Suo H, Yang S, Hou X, Yuan F, Pei Z, Dai X, Zou X, Liu F. The bHLH1-DTX35/DFR module regulates pollen fertility by promoting flavonoid biosynthesis in Capsicum annuum L. HORTICULTURE RESEARCH 2022; 9:uhac172. [PMID: 36238346 PMCID: PMC9552195 DOI: 10.1093/hr/uhac172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 07/25/2022] [Indexed: 06/16/2023]
Abstract
High pollen fertility can ensure the yield and efficiency of breeding work, but factors that affect the fertility of pepper pollen have not been studied extensively. In this work, we screened the reduced pollen fertility 1 (rpf1) mutant of Capsicum annuum with reduced pollen fertility and yellow anthers from an EMS (ethyl methanesulfonate)-mutagenized pepper population. Through construction of an F 2 population followed by BSA (bulked segregant analysis) mapping and KASP genotyping, we identified CabHLH1 as a candidate gene for control of this trait. A G → A mutation at a splice acceptor site in CabHLH1 causes a frameshift mutation in the mutant, and the translated protein is terminated prematurely. Previous studies on CabHLH1 have focused on the regulation of flavonoid synthesis. Here, we found that CabHLH1 also has an important effect on pollen fertility. Pollen vigor, anther flavonoid content, and seed number were lower in CabHLH1-silenced pepper plants, whereas anther H2O2 and MDA (malondialdehyde) contents were higher. RNA-seq analyses showed that expression of the flavonoid synthesis genes DFR, ANS, and RT was significantly reduced in anthers of CabHLH1-silenced plants and rpf1 plants, as was the expression of DTX35, a gene related to pollen fertility and flavonoid transport. Yeast one-hybrid and dual-luciferase reporter assays showed that CabHLH1 can directly bind to the promoters of DTX35 and DFR and activate their expression. These results indicate that CabHLH1 regulates reactive oxygen species homeostasis by promoting the synthesis of anther flavonoids and acts as a positive regulator of pepper pollen fertility.
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Affiliation(s)
| | | | - Qiaoling Yuan
- Engineering Research Center of Education Ministry for Germplasm Innovation and Breeding New Varieties of Horticultural Crops, Key Laboratory for Vegetable Biology of Hunan Province, College of Horticulture, Hunan Agricultural University, Changsha 410125, China
| | - Cheng Xiong
- Engineering Research Center of Education Ministry for Germplasm Innovation and Breeding New Varieties of Horticultural Crops, Key Laboratory for Vegetable Biology of Hunan Province, College of Horticulture, Hunan Agricultural University, Changsha 410125, China
| | - Hao Xu
- Engineering Research Center of Education Ministry for Germplasm Innovation and Breeding New Varieties of Horticultural Crops, Key Laboratory for Vegetable Biology of Hunan Province, College of Horticulture, Hunan Agricultural University, Changsha 410125, China
| | - Bowen Hu
- Engineering Research Center of Education Ministry for Germplasm Innovation and Breeding New Varieties of Horticultural Crops, Key Laboratory for Vegetable Biology of Hunan Province, College of Horticulture, Hunan Agricultural University, Changsha 410125, China
| | - Huan Suo
- Engineering Research Center of Education Ministry for Germplasm Innovation and Breeding New Varieties of Horticultural Crops, Key Laboratory for Vegetable Biology of Hunan Province, College of Horticulture, Hunan Agricultural University, Changsha 410125, China
| | - Sha Yang
- Engineering Research Center of Education Ministry for Germplasm Innovation and Breeding New Varieties of Horticultural Crops, Key Laboratory for Vegetable Biology of Hunan Province, College of Horticulture, Hunan Agricultural University, Changsha 410125, China
| | - Xilin Hou
- College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Fang Yuan
- Engineering Research Center of Education Ministry for Germplasm Innovation and Breeding New Varieties of Horticultural Crops, Key Laboratory for Vegetable Biology of Hunan Province, College of Horticulture, Hunan Agricultural University, Changsha 410125, China
| | - Zhenming Pei
- Engineering Research Center of Education Ministry for Germplasm Innovation and Breeding New Varieties of Horticultural Crops, Key Laboratory for Vegetable Biology of Hunan Province, College of Horticulture, Hunan Agricultural University, Changsha 410125, China
| | - Xiongze Dai
- Engineering Research Center of Education Ministry for Germplasm Innovation and Breeding New Varieties of Horticultural Crops, Key Laboratory for Vegetable Biology of Hunan Province, College of Horticulture, Hunan Agricultural University, Changsha 410125, China
| | - Xuexiao Zou
- Engineering Research Center of Education Ministry for Germplasm Innovation and Breeding New Varieties of Horticultural Crops, Key Laboratory for Vegetable Biology of Hunan Province, College of Horticulture, Hunan Agricultural University, Changsha 410125, China
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9
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Ma Z, Zhu K, Gao Y, Tan S, Miao Y. Molecular condensation and mechanoregulation of plant class I formin, an integrin‐like actin nucleator. FEBS J 2022. [DOI: 10.1111/febs.16571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 05/29/2022] [Accepted: 07/04/2022] [Indexed: 11/30/2022]
Affiliation(s)
- Zhiming Ma
- School of Biological Sciences Nanyang Technological University Singapore City Singapore
| | - Kexin Zhu
- School of Biological Sciences Nanyang Technological University Singapore City Singapore
| | - Yong‐Gui Gao
- School of Biological Sciences Nanyang Technological University Singapore City Singapore
| | - Suet‐Mien Tan
- School of Biological Sciences Nanyang Technological University Singapore City Singapore
| | - Yansong Miao
- School of Biological Sciences Nanyang Technological University Singapore City Singapore
- Institute for Digital Molecular Analytics and Science Nanyang Technological University Singapore City Singapore
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10
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Lara-Mondragón CM, Dorchak A, MacAlister CA. O-glycosylation of the extracellular domain of pollen class I formins modulates their plasma membrane mobility. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:3929-3945. [PMID: 35383367 PMCID: PMC9232206 DOI: 10.1093/jxb/erac131] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 03/31/2022] [Indexed: 06/09/2023]
Abstract
In plant cells, linkage between the cytoskeleton, plasma membrane, and cell wall is crucial for maintaining cell shape. In highly polarized pollen tubes, this coordination is especially important to allow rapid tip growth and successful fertilization. Class I formins contain cytoplasmic actin-nucleating formin homology domains as well as a proline-rich extracellular domain and are candidate coordination factors. Here, using Arabidopsis, we investigated the functional significance of the extracellular domain of two pollen-expressed class I formins: AtFH3, which does not have a polar localization, and AtFH5, which is limited to the growing tip region. We show that the extracellular domain of both is necessary for their function, and identify distinct O-glycans attached to these sequences, AtFH5 being hydroxyproline-arabinosylated and AtFH3 carrying arabinogalactan chains. Loss of hydroxyproline arabinosylation altered the plasma membrane localization of AtFH5 and disrupted actin cytoskeleton organization. Moreover, we show that O-glycans differentially affect lateral mobility in the plasma membrane. Together, our results support a model of protein sub-functionalization in which AtFH5 and AtFH3, restricted to specific plasma membrane domains by their extracellular domains and the glycans attached to them, organize distinct subarrays of actin during pollen tube elongation.
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Affiliation(s)
- Cecilia M Lara-Mondragón
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Alexandria Dorchak
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
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11
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Ren A, Zhang J, Liu Z, Du P, Zhang F, Ren H, Zhang D. OsFH13, a type I formin, is indispensable for rice morphogenesis. REPRODUCTION AND BREEDING 2022. [DOI: 10.1016/j.repbre.2022.05.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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12
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Jiang Y, Lu Q, Huang S. Functional non-equivalence of pollen ADF isovariants in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 110:1068-1081. [PMID: 35233873 DOI: 10.1111/tpj.15723] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 02/24/2022] [Accepted: 02/26/2022] [Indexed: 06/14/2023]
Abstract
ADF/cofilin is a central regulator of actin dynamics. We previously demonstrated that two closely related Arabidopsis class IIa ADF isovariants, ADF7 and ADF10, are involved in the enhancement of actin turnover in pollen, but whether they have distinct functions remains unknown. Here, we further demonstrate that they exhibit distinct functions in regulating actin turnover both in vitro and in vivo. We found that ADF7 binds to ADP-G-actin with lower affinity, and severs and depolymerizes actin filaments less efficiently in vitro than ADF10. Accordingly, in pollen grains, ADF7 more extensively decorates actin filaments and is less freely distributed in the cytoplasm compared to ADF10. We further demonstrate that ADF7 and ADF10 show distinct intracellular localizations during pollen germination, and they have non-equivalent functions in promoting actin turnover in pollen. We thus propose that cooperation and labor division of ADF7 and ADF10 enable pollen cells to achieve exquisite control of the turnover of different actin structures to meet different cellular needs.
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Affiliation(s)
- Yuxiang Jiang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Qiaonan Lu
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Shanjin Huang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
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13
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OsFH3 Encodes a Type II Formin Required for Rice Morphogenesis. Int J Mol Sci 2021; 22:ijms222413250. [PMID: 34948047 PMCID: PMC8706662 DOI: 10.3390/ijms222413250] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 12/04/2021] [Accepted: 12/06/2021] [Indexed: 02/06/2023] Open
Abstract
The actin cytoskeleton is crucial for plant morphogenesis, and organization of actin filaments (AF) is dynamically regulated by actin-binding proteins. However, the roles of actin-binding proteins, particularly type II formins, in this process remain poorly understood in plants. Here, we report that a type II formin in rice, Oryza sativa formin homolog 3 (OsFH3), acts as a major player to modulate AF dynamics and contributes to rice morphogenesis. osfh3 mutants were semi-dwarf with reduced size of seeds and unchanged responses to light or gravity compared with mutants of osfh5, another type II formin in rice. osfh3 osfh5 mutants were dwarf with more severe developmental defectiveness. Recombinant OsFH3 could nucleate actin, promote AF bundling, and cap the barbed end of AF to prevent elongation and depolymerization, but in the absence of profilin, OsFH3 could inhibit AF elongation. Different from other reported type II formins, OsFH3 could bind, but not bundle, microtubules directly. Furthermore, its N-terminal phosphatase and tensin homolog domain played a key role in modulating OsFH3 localization at intersections of AF and punctate structures of microtubules, which differed from other reported plant formins. Our results, thus, provide insights into the biological function of type II formins in modulating plant morphology by acting on AF dynamics.
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14
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Dong B, Yang Q, Song Z, Niu L, Cao H, Liu T, Du T, Yang W, Qi M, Chen T, Wang M, Jin H, Meng D, Fu Y. Hyperoside promotes pollen tube growth by regulating the depolymerization effect of actin-depolymerizing factor 1 on microfilaments in okra. HORTICULTURE RESEARCH 2021; 8:145. [PMID: 34193835 PMCID: PMC8245483 DOI: 10.1038/s41438-021-00578-z] [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: 01/20/2021] [Revised: 03/14/2021] [Accepted: 04/07/2021] [Indexed: 06/13/2023]
Abstract
Mature pollen germinates rapidly on the stigma, extending its pollen tube to deliver sperm cells to the ovule for fertilization. The success of this process is an important factor that limits output. The flavonoid content increased significantly during pollen germination and pollen tube growth, which suggests it may play an important role in these processes. However, the specific mechanism of this involvement has been little researched. Our previous research found that hyperoside can prolong the flowering period of Abelmoschus esculentus (okra), but its specific mechanism is still unclear. Therefore, in this study, we focused on the effect of hyperoside in regulating the actin-depolymerizing factor (ADF), which further affects the germination and growth of pollen. We found that hyperoside can prolong the effective pollination period of okra by 2-3-fold and promote the growth of pollen tubes in the style. Then, we used Nicotiana benthamiana cells as a research system and found that hyperoside accelerates the depolymerization of intercellular microfilaments. Hyperoside can promote pollen germination and pollen tube elongation in vitro. Moreover, AeADF1 was identified out of all AeADF genes as being highly expressed in pollen tubes in response to hyperoside. In addition, hyperoside promoted AeADF1-mediated microfilament dissipation according to microfilament severing experiments in vitro. In the pollen tube, the gene expression of AeADF1 was reduced to 1/5 by oligonucleotide transfection. The decrease in the expression level of AeADF1 partially reduced the promoting effect of hyperoside on pollen germination and pollen tube growth. This research provides new research directions for flavonoids in reproductive development.
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Affiliation(s)
- Biying Dong
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, College of Forestry, Beijing Forestry University, Beijing, 100000, China
| | - Qing Yang
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, College of Forestry, Beijing Forestry University, Beijing, 100000, China
| | - Zhihua Song
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, College of Forestry, Beijing Forestry University, Beijing, 100000, China
| | - Lili Niu
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, College of Forestry, Beijing Forestry University, Beijing, 100000, China
| | - Hongyan Cao
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, College of Forestry, Beijing Forestry University, Beijing, 100000, China
| | - Tengyue Liu
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, College of Forestry, Beijing Forestry University, Beijing, 100000, China
| | - Tingting Du
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, College of Forestry, Beijing Forestry University, Beijing, 100000, China
| | - Wanlong Yang
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, College of Forestry, Beijing Forestry University, Beijing, 100000, China
| | - Meng Qi
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, College of Forestry, Beijing Forestry University, Beijing, 100000, China
| | - Ting Chen
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, College of Forestry, Beijing Forestry University, Beijing, 100000, China
| | - Mengying Wang
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, College of Forestry, Beijing Forestry University, Beijing, 100000, China
| | - Haojie Jin
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, College of Forestry, Beijing Forestry University, Beijing, 100000, China
| | - Dong Meng
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, College of Forestry, Beijing Forestry University, Beijing, 100000, China.
| | - Yujie Fu
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, College of Forestry, Beijing Forestry University, Beijing, 100000, China.
- Key Laboratory of Forest Plant Ecology, Ministry of Education, Northeast Forestry University, Harbin, 150000, China.
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15
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Zhang L, Smertenko T, Fahy D, Koteyeva N, Moroz N, Kuchařová A, Novák D, Manoilov E, Smertenko P, Galva C, Šamaj J, Kostyukova AS, Sedbrook JC, Smertenko A. Analysis of formin functions during cytokinesis using specific inhibitor SMIFH2. PLANT PHYSIOLOGY 2021; 186:945-963. [PMID: 33620500 PMCID: PMC8195507 DOI: 10.1093/plphys/kiab085] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 02/03/2021] [Indexed: 05/10/2023]
Abstract
The phragmoplast separates daughter cells during cytokinesis by constructing the cell plate, which depends on interaction between cytoskeleton and membrane compartments. Proteins responsible for these interactions remain unknown, but formins can link cytoskeleton with membranes and several members of formin protein family localize to the cell plate. Progress in functional characterization of formins in cytokinesis is hindered by functional redundancies within the large formin gene family. We addressed this limitation by employing Small Molecular Inhibitor of Formin Homology 2 (SMIFH2), a small-molecule inhibitor of formins. Treatment of tobacco (Nicotiana tabacum) tissue culture cells with SMIFH2 perturbed localization of actin at the cell plate; slowed down both microtubule polymerization and phragmoplast expansion; diminished association of dynamin-related proteins with the cell plate independently of actin and microtubules; and caused cell plate swelling. Another impact of SMIFH2 was shortening of the END BINDING1b (EB1b) and EB1c comets on the growing microtubule plus ends in N. tabacum tissue culture cells and Arabidopsis thaliana cotyledon epidermis cells. The shape of the EB1 comets in the SMIFH2-treated cells resembled that of the knockdown mutant of plant Xenopus Microtubule-Associated protein of 215 kDa (XMAP215) homolog MICROTUBULE ORGANIZATION 1/GEMINI 1 (MOR1/GEM1). This outcome suggests that formins promote elongation of tubulin flares on the growing plus ends. Formins AtFH1 (A. thaliana Formin Homology 1) and AtFH8 can also interact with EB1. Besides cytokinesis, formins function in the mitotic spindle assembly and metaphase to anaphase transition. Our data suggest that during cytokinesis formins function in: (1) promoting microtubule polymerization; (2) nucleating F-actin at the cell plate; (3) retaining dynamin-related proteins at the cell plate; and (4) remodeling of the cell plate membrane.
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Affiliation(s)
- Laining Zhang
- Institute of Biological Chemistry, Washington State University, Pullman, Washington, USA
| | - Tetyana Smertenko
- Institute of Biological Chemistry, Washington State University, Pullman, Washington, USA
| | - Deirdre Fahy
- Institute of Biological Chemistry, Washington State University, Pullman, Washington, USA
| | - Nuria Koteyeva
- Laboratory of Anatomy and Morphology, Komarov Botanical Institute of Russian Academy of Sciences, St. Petersburg 197376, Russia
| | - Natalia Moroz
- The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, Washington, USA
| | - Anna Kuchařová
- Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, 783 71 Olomouc, Czech Republic
| | - Dominik Novák
- Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, 783 71 Olomouc, Czech Republic
| | - Eduard Manoilov
- V. Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine, Kyiv, Ukraine
| | - Petro Smertenko
- V. Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine, Kyiv, Ukraine
| | - Charitha Galva
- School of Biological Sciences, Illinois State University, Normal, Illinois, USA
| | - Jozef Šamaj
- Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, 783 71 Olomouc, Czech Republic
| | - Alla S. Kostyukova
- The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, Washington, USA
| | - John C. Sedbrook
- School of Biological Sciences, Illinois State University, Normal, Illinois, USA
| | - Andrei Smertenko
- Institute of Biological Chemistry, Washington State University, Pullman, Washington, USA
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16
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Liu C, Zhang Y, Ren H. Profilin promotes formin-mediated actin filament assembly and vesicle transport during polarity formation in pollen. THE PLANT CELL 2021; 33:1252-1267. [PMID: 33638636 DOI: 10.1093/plcell/koab027] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 01/20/2021] [Indexed: 06/12/2023]
Abstract
Pollen germination is critical for the reproduction of flowering plants. Formin-dependent actin polymerization plays vital roles in vesicle trafficking and polarity establishment during this process. However, how formin-mediated actin assembly is regulated in vivo remains poorly understood. Here, we investigated the function of reproductive profilin 4 and 5 (PRF4 and PRF5) in polarity establishment during pollen germination in Arabidopsis thaliana. Our data showed that the actin filament content was reduced in the prf4 prf5 double mutant and substantially increased in both PRF4- and PRF5-overexpressing pollen grains. By contrast, the positive effect of profilin in promoting actin polymerization was abolished in a formin mutant, atfh5. In addition, the interaction between Arabidopsis formin homology 5 (AtFH5) and actin filaments was attenuated and the trafficking of AtFH5-labeled vesicles was slowed in prf4 prf5 pollen grains. Formation of the collar-like structure at the germination pore was also defective in prf4 prf5 pollen grains as the fast assembly of actin filaments was impaired. Together, our results suggest that PRF4 and PRF5 regulate vesicle trafficking and polarity establishment during pollen germination by promoting AtFH5-mediated actin polymerization and enhancing the interaction between AtFH5 and actin filaments.
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Affiliation(s)
- Chang Liu
- Center for Biological Science and Technology, Institute of Natural Science, Beijing Normal University, Zhuhai 519087, China
| | - Yi Zhang
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Science, Beijing Normal University, Beijing 100875, China
| | - Haiyun Ren
- Center for Biological Science and Technology, Institute of Natural Science, Beijing Normal University, Zhuhai 519087, China
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Science, Beijing Normal University, Beijing 100875, China
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17
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Hayashi M, Palmgren M. The quest for the central players governing pollen tube growth and guidance. PLANT PHYSIOLOGY 2021; 185:682-693. [PMID: 33793904 PMCID: PMC8133568 DOI: 10.1093/plphys/kiaa092] [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: 11/18/2020] [Accepted: 12/06/2020] [Indexed: 05/02/2023]
Abstract
Recent insights into the mechanism of pollen tube growth and guidance point to the importance of H+ dynamics, which are regulated by the plasma membrane H+-ATPase.
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Affiliation(s)
- Maki Hayashi
- Department for Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, Copenhagen, Denmark
| | - Michael Palmgren
- Department for Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, Copenhagen, Denmark
- International Research Centre for Environmental Membrane Biology, Foshan University, Foshan 528000,China
- Author for communication:
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18
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Diao M, Huang S. An Update on the Role of the Actin Cytoskeleton in Plasmodesmata: A Focus on Formins. FRONTIERS IN PLANT SCIENCE 2021; 12:647123. [PMID: 33659020 PMCID: PMC7917184 DOI: 10.3389/fpls.2021.647123] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 01/26/2021] [Indexed: 06/12/2023]
Abstract
Cell-to-cell communication in plants is mediated by plasmodesmata (PD) whose permeability is tightly regulated during plant growth and development. The actin cytoskeleton has been implicated in regulating the permeability of PD, but the underlying mechanism remains largely unknown. Recent characterization of PD-localized formin proteins has shed light on the role and mechanism of action of actin in regulating PD-mediated intercellular trafficking. In this mini-review article, we will describe the progress in this area.
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Affiliation(s)
- Min Diao
- iHuman Institute, Shanghai Tech University, Shanghai, China
| | - Shanjin Huang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
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19
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Du P, Wang J, He Y, Zhang S, Hu B, Xue X, Miao L, Ren H. AtFH14 crosslinks actin filaments and microtubules in different manners. Biol Cell 2021; 113:235-249. [PMID: 33386758 DOI: 10.1111/boc.202000147] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 12/16/2020] [Accepted: 12/18/2020] [Indexed: 12/23/2022]
Abstract
BACKGROUND INFORMATION In many cellular processes including cell division, the synergistic dynamics of actin filaments and microtubules play vital roles. However, the regulatory mechanisms of these synergistic dynamics are not fully understood. Proteins such as formins are involved in actin filament-microtubule interactions and Arabidopsis thaliana formin 14 (AtFH14) may function as a crosslinker between actin filaments and microtubules in cell division, but the molecular mechanism underlying such crosslinking remains unclear. RESULTS Without microtubules, formin homology (FH) 1/FH2 of AtFH14 nucleated actin polymerisation from actin monomers and capped the barbed end of actin filaments. However, in the presence of microtubules, quantitative analysis showed that the binding affinity of AtFH14 FH1FH2 to microtubules was higher than that to actin filaments. Moreover, microtubule-bound AtFH14 FH1FH2 neither nucleated actin polymerisation nor inhibited barbed end elongation. In contrast, tubulin did not affect AtFH14 FH1FH2 to nucleate actin polymerisation and inhibit barbed end elongation. Nevertheless, microtubule-bound AtFH14 FH1FH2 bound actin filaments and the bound actin filaments slid and elongated along the microtubules or elongated away from the microtubules, which induced bundling or crosslinking of actin filaments and microtubules. Pharmacological analyses indicated that AtFH14 FH1FH2 promoted crosslinking of actin filaments and microtubules in vivo. Additionally, co-sedimentation and fluorescent dye-labelling experiments of AtFH14 FH2-truncated proteins in vitro revealed the essential motifs of bundling actin filaments or microtubules, which were 63-92 aa and 42-62 aa in the AtFH14 FH2 N-terminal, respectively, and 42-62 aa was the essential motif to crosslink actin filaments and microtubules. CONCLUSIONS AND SIGNIFICANCE Our results aid in explaining how AtFH14 functions as a crosslinker between actin filaments and microtubules to regulate their dynamics via different manners during cell division. They also facilitate further understanding of the molecular mechanisms of the interactions between actin filaments and microtubules.
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Affiliation(s)
- Pingzhou Du
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, Center for Biological Science and Technology, Advanced Institute of Natural Science, Beijing Normal University, Zhuhai, 519087, China
| | - Jiaojiao Wang
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, Center for Biological Science and Technology, Advanced Institute of Natural Science, Beijing Normal University, Zhuhai, 519087, China
| | - Yunqiu He
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, Center for Biological Science and Technology, Advanced Institute of Natural Science, Beijing Normal University, Zhuhai, 519087, China
| | - Sha Zhang
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, Center for Biological Science and Technology, Advanced Institute of Natural Science, Beijing Normal University, Zhuhai, 519087, China
| | - Bailing Hu
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, Center for Biological Science and Technology, Advanced Institute of Natural Science, Beijing Normal University, Zhuhai, 519087, China
| | - Xiuhua Xue
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, Center for Biological Science and Technology, Advanced Institute of Natural Science, Beijing Normal University, Zhuhai, 519087, China
| | - Long Miao
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Haiyun Ren
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, Center for Biological Science and Technology, Advanced Institute of Natural Science, Beijing Normal University, Zhuhai, 519087, China
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20
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Ruan H, Li J, Wang T, Ren H. Secretory Vesicles Targeted to Plasma Membrane During Pollen Germination and Tube Growth. Front Cell Dev Biol 2021; 8:615447. [PMID: 33553150 PMCID: PMC7859277 DOI: 10.3389/fcell.2020.615447] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 12/14/2020] [Indexed: 12/12/2022] Open
Abstract
Pollen germination and pollen tube growth are important biological events in the sexual reproduction of higher plants, during which a large number of vesicle trafficking and membrane fusion events occur. When secretory vesicles are transported via the F-actin network in proximity to the apex of the pollen tube, the secretory vesicles are tethered and fused to the plasma membrane by tethering factors and SNARE proteins, respectively. The coupling and uncoupling between the vesicle membrane and plasma membrane are also regulated by dynamic cytoskeleton, proteins, and signaling molecules, including small G proteins, calcium, and PIP2. In this review, we focus on the current knowledge regarding secretory vesicle delivery, tethering, and fusion during pollen germination and tube growth and summarize the progress in research on how regulators and signaling molecules participate in the above processes.
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Affiliation(s)
- Huaqiang Ruan
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, Center for Biological Science and Technology, Advanced Institute of Natural Science, Beijing Normal University, Zhuhai, China
| | - Jiang Li
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, Center for Biological Science and Technology, Advanced Institute of Natural Science, Beijing Normal University, Zhuhai, China
| | - Ting Wang
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, Center for Biological Science and Technology, Advanced Institute of Natural Science, Beijing Normal University, Zhuhai, China
| | - Haiyun Ren
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, Center for Biological Science and Technology, Advanced Institute of Natural Science, Beijing Normal University, Zhuhai, China
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21
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Kollárová E, Baquero Forero A, Cvrčková F. The Arabidopsis thaliana Class II Formin FH13 Modulates Pollen Tube Growth. FRONTIERS IN PLANT SCIENCE 2021; 12:599961. [PMID: 33679824 PMCID: PMC7929981 DOI: 10.3389/fpls.2021.599961] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 01/29/2021] [Indexed: 05/10/2023]
Abstract
Formins are a large, evolutionarily conserved family of actin-nucleating proteins with additional roles in regulating microfilament, microtubule, and membrane dynamics. Angiosperm formins, expressed in both sporophytic and gametophytic tissues, can be divided into two subfamilies, Class I and Class II, each often exhibiting characteristic domain organization. Gametophytically expressed Class I formins have been documented to mediate plasma membrane-based actin assembly in pollen grains and pollen tubes, contributing to proper pollen germination and pollen tube tip growth, and a rice Class II formin, FH5/RMD, has been proposed to act as a positive regulator of pollen tube growth based on mutant phenotype and overexpression data. Here we report functional characterization of the Arabidopsis thaliana pollen-expressed typical Class II formin FH13 (At5g58160). Consistent with published transcriptome data, live-cell imaging in transgenic plants expressing fluorescent protein-tagged FH13 under the control of the FH13 promoter revealed expression in pollen and pollen tubes with non-homogeneous signal distribution in pollen tube cytoplasm, suggesting that this formin functions in the male gametophyte. Surprisingly, fh13 loss of function mutations do not affect plant fertility but result in stimulation of in vitro pollen tube growth, while tagged FH13 overexpression inhibits pollen tube elongation. Pollen tubes of mutants expressing a fluorescent actin marker exhibited possible minor alterations of actin organization. Our results thus indicate that FH13 controls or limits pollen tube growth, or, more generally, that typical Class II formins should be understood as modulators of pollen tube elongation rather than merely components of the molecular apparatus executing tip growth.
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22
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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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23
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Beuder S, Dorchak A, Bhide A, Moeller SR, Petersen BL, MacAlister CA. Exocyst mutants suppress pollen tube growth and cell wall structural defects of hydroxyproline O-arabinosyltransferase mutants. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 103:1399-1419. [PMID: 32391581 PMCID: PMC7496944 DOI: 10.1111/tpj.14808] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 04/22/2020] [Accepted: 04/28/2020] [Indexed: 05/07/2023]
Abstract
HYDROXYPROLINE O-ARABINOSYLTRANSFERASEs (HPATs) initiate a post-translational protein modification (Hyp-Ara) found abundantly on cell wall structural proteins. In Arabidopsis thaliana, HPAT1 and HPAT3 are redundantly required for full pollen fertility. In addition to the lack of Hyp-Ara in hpat1/3 pollen tubes (PTs), we also found broadly disrupted cell wall polymer distributions, particularly the conversion of the tip cell wall to a more shaft-like state. Mutant PTs were slow growing and prone to rupture and morphological irregularities. In a forward mutagenesis screen for suppressors of the hpat1/3 low seed-set phenotype, we identified a missense mutation in exo70a2, a predicted member of the vesicle-tethering exocyst complex. The suppressed pollen had increased fertility, fewer morphological defects and partially rescued cell wall organization. A transcriptional null allele of exo70a2 also suppressed the hpat1/3 fertility phenotype, as did mutants of core exocyst complex member sec15a, indicating that reduced exocyst function bypassed the PT requirement for Hyp-Ara. In a wild-type background, exo70a2 reduced male transmission efficiency, lowered pollen germination frequency and slowed PT elongation. EXO70A2 also localized to the PT tip plasma membrane, consistent with a role in exocyst-mediated secretion. To monitor the trafficking of Hyp-Ara modified proteins, we generated an HPAT-targeted fluorescent secretion reporter. Reporter secretion was partially dependent on EXO70A2 and was significantly increased in hpat1/3 PTs compared with the wild type, but was reduced in the suppressed exo70a2 hpat1/3 tubes.
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Affiliation(s)
- Steven Beuder
- Department of Molecular, Cellular and Developmental BiologyUniversity of Michigan1105 N. University AveAnn ArborMI48109USA
| | - Alexandria Dorchak
- Department of Molecular, Cellular and Developmental BiologyUniversity of Michigan1105 N. University AveAnn ArborMI48109USA
| | - Ashwini Bhide
- Department of Molecular, Cellular and Developmental BiologyUniversity of Michigan1105 N. University AveAnn ArborMI48109USA
| | - Svenning Rune Moeller
- Department of Plant and Environmental SciencesFaculty of ScienceUniversity of CopenhagenThorvaldsensvej 40København1871 Frederiksberg CDenmark
| | - Bent L. Petersen
- Department of Plant and Environmental SciencesFaculty of ScienceUniversity of CopenhagenThorvaldsensvej 40København1871 Frederiksberg CDenmark
| | - Cora A. MacAlister
- Department of Molecular, Cellular and Developmental BiologyUniversity of Michigan1105 N. University AveAnn ArborMI48109USA
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Abstract
Cell polarity in plants operates across a broad range of spatial and temporal scales to control processes from acute cell growth to systemic hormone distribution. Similar to other eukaryotes, plants generate polarity at both the subcellular and tissue levels, often through polarization of membrane-associated protein complexes. However, likely due to the constraints imposed by the cell wall and their extremely plastic development, plants possess novel polarity molecules and mechanisms highly tuned to environmental inputs. Considerable progress has been made in identifying key plant polarity regulators, but detailed molecular understanding of polarity mechanisms remains incomplete in plants. Here, we emphasize the striking similarities in the conceptual frameworks that generate polarity in both animals and plants. To this end, we highlight how novel, plant-specific proteins engage in common themes of positive feedback, dynamic intracellular trafficking, and posttranslational regulation to establish polarity axes in development. We end with a discussion of how environmental signals control intrinsic polarity to impact postembryonic organogenesis and growth.
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Affiliation(s)
- Andrew Muroyama
- Howard Hughes Medical Institute, Stanford University, Stanford, California 94305-5020, USA; .,Department of Biology, Stanford University, Stanford, California 94305-5020, USA
| | - Dominique Bergmann
- Howard Hughes Medical Institute, Stanford University, Stanford, California 94305-5020, USA; .,Department of Biology, Stanford University, Stanford, California 94305-5020, USA
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25
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Arabidopsis FHY3 and FAR1 integrate light and strigolactone signaling to regulate branching. Nat Commun 2020; 11:1955. [PMID: 32327664 PMCID: PMC7181604 DOI: 10.1038/s41467-020-15893-7] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Accepted: 04/01/2020] [Indexed: 11/10/2022] Open
Abstract
Branching/tillering is an important parameter of plant architecture and is tightly regulated by both internal factors (such as plant hormones) and external factors (such as light conditions). How the various signaling pathways converge to coordinately regulate branching is not well understood. Here, we report that in Arabidopsis, FHY3 and FAR1, two homologous transcription factors essential for phytochrome A-mediated light signaling, and SMXL6/SMXL7/SMXL8, three key repressors of the strigolactone (SL) signaling pathway, directly interact with SPL9 and SPL15 and suppress their transcriptional activation of BRC1, a key repressor of branching, thus promoting branching. In addition, FHY3 and FAR1 also directly up-regulate the expression of SMXL6 and SMXL7 to promote branching. Simulated shade treatment reduces the accumulation of FHY3 protein, leading to increased expression of BRC1 and reduced branching. Our results establish an integrated model of light and SL coordinately regulating BRC1 expression and branching through converging at the BRC1 promoter. In plants, branching is regulated by both hormones and external cues such as light. Here the authors show that in Arabidopsis, the phytochrome A-signaling components FHY3 and FAR1, and SMXL proteins that repress strigolactone signaling, both interact with SPL proteins to control expression of the branching regulator BRC1.
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26
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Zhao W, Qu X, Zhuang Y, Wang L, Bosch M, Franklin-Tong VE, Xue Y, Huang S. Villin controls the formation and enlargement of punctate actin foci in pollen tubes. J Cell Sci 2020; 133:jcs237404. [PMID: 32051284 DOI: 10.1242/jcs.237404] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 02/01/2020] [Indexed: 11/20/2022] Open
Abstract
Self-incompatibility (SI) in the poppy Papaver rhoeas triggers dramatic alterations in actin within pollen tubes. However, how these actin alterations are mechanistically achieved remains largely unexplored. Here, we used treatment with the Ca2+ ionophore A23187 to mimic the SI-induced elevation in cytosolic Ca2+ and trigger formation of the distinctive F-actin foci. Live-cell imaging revealed that this remodeling involves F-actin fragmentation and depolymerization, accompanied by the rapid formation of punctate actin foci and subsequent increase in their size. We established that actin foci are generated and enlarged from crosslinking of fragmented actin filament structures. Moreover, we show that villins associate with actin structures and are involved in this actin reorganization process. Notably, we demonstrate that Arabidopsis VILLIN5 promotes actin depolymerization and formation of actin foci by fragmenting actin filaments, and controlling the enlargement of actin foci via bundling of actin filaments. Our study thus uncovers important novel insights about the molecular players and mechanisms involved in forming the distinctive actin foci in pollen tubes.
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Affiliation(s)
- Wanying Zhao
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Xiaolu Qu
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, China
| | - Yuhui Zhuang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Ludi Wang
- Institute of Biological, Environmental and Rural Sciences (IBERS), Aberystwyth University, Plas Gogerddan, Aberystwyth, SY23 3EE, UK
| | - Maurice Bosch
- Institute of Biological, Environmental and Rural Sciences (IBERS), Aberystwyth University, Plas Gogerddan, Aberystwyth, SY23 3EE, UK
| | - Vernonica E Franklin-Tong
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Yongbiao Xue
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
- Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Shanjin Huang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
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27
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Proost S, Mutwil M. CoNekT: an open-source framework for comparative genomic and transcriptomic network analyses. Nucleic Acids Res 2019; 46:W133-W140. [PMID: 29718322 PMCID: PMC6030989 DOI: 10.1093/nar/gky336] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Accepted: 04/18/2018] [Indexed: 12/22/2022] Open
Abstract
The recent accumulation of gene expression data in the form of RNA sequencing creates unprecedented opportunities to study gene regulation and function. Furthermore, comparative analysis of the expression data from multiple species can elucidate which functional gene modules are conserved across species, allowing the study of the evolution of these modules. However, performing such comparative analyses on raw data is not feasible for many biologists. Here, we present CoNekT (Co-expression Network Toolkit), an open source web server, that contains user-friendly tools and interactive visualizations for comparative analyses of gene expression data and co-expression networks. These tools allow analysis and cross-species comparison of (i) gene expression profiles; (ii) co-expression networks; (iii) co-expressed clusters involved in specific biological processes; (iv) tissue-specific gene expression; and (v) expression profiles of gene families. To demonstrate these features, we constructed CoNekT-Plants for green alga, seed plants and flowering plants (Picea abies, Chlamydomonas reinhardtii, Vitis vinifera, Arabidopsis thaliana, Oryza sativa, Zea mays and Solanum lycopersicum) and thus provide a web-tool with the broadest available collection of plant phyla. CoNekT-Plants is freely available from http://conekt.plant.tools, while the CoNekT source code and documentation can be found at https://github.molgen.mpg.de/proost/CoNekT/.
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Affiliation(s)
- Sebastian Proost
- Max-Planck Institute for Molecular Plant Physiology, Am Muehlenberg 1, 14476 Potsdam, Germany
| | - Marek Mutwil
- Max-Planck Institute for Molecular Plant Physiology, Am Muehlenberg 1, 14476 Potsdam, Germany.,School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
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28
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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.
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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.
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29
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Mechanism of CAP1-mediated apical actin polymerization in pollen tubes. Proc Natl Acad Sci U S A 2019; 116:12084-12093. [PMID: 31123151 DOI: 10.1073/pnas.1821639116] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Srv2p/CAP1 is an essential regulator of actin turnover, but its exact function in regulating actin polymerization, particularly the contribution of its actin nucleotide exchange activity, remains incompletely understood. We found that, although Arabidopsis CAP1 is distributed uniformly in the cytoplasm, its loss of function has differential effects on the actin cytoskeleton within different regions of the pollen tube. Specifically, the F-actin level increases in the shank but decreases in the apical region of cap1 pollen tubes. The reduction in apical F-actin results mainly from impaired polymerization of membrane-originated actin within cap1 pollen tubes. The actin nucleotide exchange activity of CAP1 is involved in apical actin polymerization. CAP1 acts synergistically with pollen ADF and profilin to promote actin turnover in vitro, and it can overcome the inhibitory effects of ADF and synergize with profilin to promote actin nucleotide exchange. Consistent with its role as a shuttle molecule between ADF and profilin, the cytosolic concentration of CAP1 is much lower than that of ADF and profilin in pollen. Thus, CAP1 synergizes with ADF and profilin to drive actin turnover in pollen and promote apical actin polymerization in pollen tubes in a manner that involves its actin nucleotide exchange activity.
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30
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Zhang S, Wang C, Xie M, Liu J, Kong Z, Su H. Actin Bundles in The Pollen Tube. Int J Mol Sci 2018; 19:ijms19123710. [PMID: 30469514 PMCID: PMC6321563 DOI: 10.3390/ijms19123710] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Revised: 11/18/2018] [Accepted: 11/19/2018] [Indexed: 12/31/2022] Open
Abstract
The angiosperm pollen tube delivers two sperm cells into the embryo sac through a unique growth strategy, named tip growth, to accomplish fertilization. A great deal of experiments have demonstrated that actin bundles play a pivotal role in pollen tube tip growth. There are two distinct actin bundle populations in pollen tubes: the long, rather thick actin bundles in the shank and the short, highly dynamic bundles near the apex. With the development of imaging techniques over the last decade, great breakthroughs have been made in understanding the function of actin bundles in pollen tubes, especially short subapical actin bundles. Here, we tried to draw an overall picture of the architecture, functions and underlying regulation mechanism of actin bundles in plant pollen tubes.
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Affiliation(s)
- Shujuan Zhang
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education College of Life Science, Northwest University, Xi'an 710069, China.
| | - Chunbo Wang
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education College of Life Science, Northwest University, Xi'an 710069, China.
| | - Min Xie
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education College of Life Science, Northwest University, Xi'an 710069, China.
| | - Jinyu Liu
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education College of Life Science, Northwest University, Xi'an 710069, China.
| | - Zhe Kong
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education College of Life Science, Northwest University, Xi'an 710069, China.
| | - Hui Su
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education College of Life Science, Northwest University, Xi'an 710069, China.
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31
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Arabidopsis class I formins control membrane-originated actin polymerization at pollen tube tips. PLoS Genet 2018; 14:e1007789. [PMID: 30418966 PMCID: PMC6258422 DOI: 10.1371/journal.pgen.1007789] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 11/26/2018] [Accepted: 10/25/2018] [Indexed: 12/17/2022] Open
Abstract
A population of dynamic apical actin filaments is required for rapid polarized pollen tube growth. However, the cellular mechanisms driving their assembly remain incompletely understood. It was postulated that formin is a major player in nucleating apical actin assembly, but direct genetic and cytological evidence remains to be firmly established. Here we found that both Arabidopsis formin 3 (AtFH3) and formin 5 (AtFH5) are involved in the regulation of apical actin polymerization and actin array construction in pollen tubes, with AtFH3 playing a more dominant role. We found that both formins have plasma membrane (PM) localization signals but exhibit distinct PM localization patterns in the pollen tube, and loss of their function reduces the amount of apical actin filaments. Live-cell imaging revealed that the reduction in filamentous actin is very likely due to the decrease in filament elongation. Furthermore, we found that the rate of tip-directed vesicle transport is reduced and the pattern of apical vesicle accumulation is altered in formin loss-of-function mutant pollen tubes, which explains to some extent the reduction in pollen tube elongation. Thus, we provide direct genetic and cytological evidence showing that formin is an important player in nucleating actin assembly from the PM at pollen tube tips. Actin polymerization has been implicated in the regulation of rapid polarized pollen tube growth. The important role of actin polymerization is well appreciated, but the mechanisms that regulate rapid actin polymerization in pollen tubes remain incompletely understood. It was postulated that one of the major actin polymerization pathways in pollen tubes involves formin/profilin modules. However, direct genetic and cytological evidence is still required to support the role of formin in this framework. Using state-of-the-art live-cell imaging in combination with reverse genetic approaches, we demonstrate here that two class I formins, Arabidopsis formin 3 (AtFH3) and formin 5 (AtFH5), are involved in the regulation of apical actin polymerization and actin array construction in pollen tubes. In support of the role of AtFH3 and AtFH5 in regulating membrane-originated apical actin polymerization, we found that both of them are localized to the plasma membrane (PM) at pollen tube tips. Live-cell imaging revealed that the reduction in filamentous actin is very likely due to the decrease in elongation of actin filaments originating from the apical membrane. We also found that AtFH3 and AtFH5 exhibit distinct PM localization patterns in the pollen tube, suggesting that they might have distinct roles in regulating actin polymerization in pollen tubes. Our study provides direct genetic and cytological evidence that formins act as important players in regulating apical actin assembly in pollen tubes.
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32
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Diao M, Ren S, Wang Q, Qian L, Shen J, Liu Y, Huang S. Arabidopsis formin 2 regulates cell-to-cell trafficking by capping and stabilizing actin filaments at plasmodesmata. eLife 2018; 7:e36316. [PMID: 30113309 PMCID: PMC6126924 DOI: 10.7554/elife.36316] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 08/15/2018] [Indexed: 11/13/2022] Open
Abstract
Here, we demonstrate that Arabidopsis thaliana Formin 2 (AtFH2) localizes to plasmodesmata (PD) through its transmembrane domain and is required for normal intercellular trafficking. Although loss-of-function atfh2 mutants have no overt developmental defect, PD's permeability and sensitivity to virus infection are increased in atfh2 plants. Interestingly, AtFH2 functions in a partially redundant manner with its closest homolog AtFH1, which also contains a PD localization signal. Strikingly, targeting of Class I formins to PD was also confirmed in rice, suggesting that the involvement of Class I formins in regulating actin dynamics at PD may be evolutionarily conserved in plants. In vitro biochemical analysis showed that AtFH2 fails to nucleate actin assembly but caps and stabilizes actin filaments. We also demonstrate that the interaction between AtFH2 and actin filaments is crucial for its function in vivo. These data allow us to propose that AtFH2 regulates PD's permeability by anchoring actin filaments to PD.
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Affiliation(s)
- Min Diao
- Center for Plant Biology, School of Life SciencesTsinghua UniversityBeijingChina
- Institute of Botany, Chinese Academy of SciencesBeijingChina
- University of Chinese Academy of SciencesBeijingChina
| | - Sulin Ren
- Institute of Botany, Chinese Academy of SciencesBeijingChina
| | - Qiannan Wang
- Center for Plant Biology, School of Life SciencesTsinghua UniversityBeijingChina
| | - Lichao Qian
- Center for Plant Biology, School of Life SciencesTsinghua UniversityBeijingChina
- MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Center for Life SciencesTsinghua UniversityBeijingChina
| | - Jiangfeng Shen
- Center for Plant Biology, School of Life SciencesTsinghua UniversityBeijingChina
| | - Yule Liu
- Center for Plant Biology, School of Life SciencesTsinghua UniversityBeijingChina
- MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Center for Life SciencesTsinghua UniversityBeijingChina
| | - Shanjin Huang
- Center for Plant Biology, School of Life SciencesTsinghua UniversityBeijingChina
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33
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Sun H, Qiao Z, Chua KP, Tursic A, Liu X, Gao YG, Mu Y, Hou X, Miao Y. Profilin Negatively Regulates Formin-Mediated Actin Assembly to Modulate PAMP-Triggered Plant Immunity. Curr Biol 2018; 28:1882-1895.e7. [PMID: 29861135 DOI: 10.1016/j.cub.2018.04.045] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 03/01/2018] [Accepted: 04/13/2018] [Indexed: 11/26/2022]
Abstract
Profilin functions with formin in actin assembly, a process that regulates multiple aspects of plant development and immune responses. High-level eukaryotes contain multiple isoforms of profilin, formin, and actin, whose partner-specific interactions in actin assembly are not completely understood in plant development and defense responses. To examine the functionally distinct interactions between profilin and formin, we studied all five Arabidopsis profilins and their interactions with formin by using both in vitro biochemical and in vivo cell biology approaches. Unexpectedly, we found a previously undescribed negative regulatory function of AtPRF3 in AtFH1-mediated actin polymerization. The N-terminal 37 residues of AtPRF3 were identified to play a predominant role in inhibiting formin-mediated actin nucleation via their high affinity for the formin polyproline region and their triggering of the oligomerization of AtPRF3. Both in vivo and in vitro mechanistic studies of AtPRF3 revealed a universal mechanism in which the weak interaction between profilin and formin positively regulates actin assembly by ensuring rapid recycling of profilin, whereas profilin oligomerization negatively regulates actin polymerization. Upon recognition of the pathogen-associated molecular pattern, the gene transcription and protein degradation of AtPRF3 are modulated for actin assembly during plant innate immunity. The prf3 Arabidopsis plants show higher sensitivity to the bacterial flagellum peptide in both the plant growth and ROS responses. These findings demonstrate a profilin-mediated actin assembly mechanism underlying the plant immune responses.
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Affiliation(s)
- He Sun
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Zhu Qiao
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Khi Pin Chua
- Interdisciplinary Graduate School, Nanyang Technological University, Singapore 637371, Singapore
| | - Alma Tursic
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Xu Liu
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement & Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Yong-Gui Gao
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore; Institute of Molecular and Cell Biology, A(∗)STAR, Singapore 138673, Singapore
| | - Yuguang Mu
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Xingliang Hou
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement & Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Yansong Miao
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore; School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637459, Singapore.
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34
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Li G, Yang X, Zhang X, Song Y, Liang W, Zhang D. Rice Morphology Determinant-Mediated Actin Filament Organization Contributes to Pollen Tube Growth. PLANT PHYSIOLOGY 2018; 177:255-270. [PMID: 29581178 PMCID: PMC5933118 DOI: 10.1104/pp.17.01759] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Accepted: 03/19/2018] [Indexed: 05/25/2023]
Abstract
For successful fertilization in angiosperms, rapid tip growth in pollen tubes delivers the male gamete into the ovules. The actin-binding protein-mediated organization of the actin cytoskeleton within the pollen tube plays a crucial role in this polarized process. However, the mechanism underlying the polarity of the actin filament (F-actin) array and behaviors in pollen tube growth remain largely unknown. Here, we demonstrate that an actin-organizing protein, Rice Morphology Determinant (RMD), a type II formin from rice (Oryza sativa), controls pollen tube growth by modulating the polarity and distribution of the F-actin array. The rice rmd mutant exhibits abnormal pollen tube growth and a decreased germination rate of the pollen grain in vitro and in vivo. The rmd pollen tubes display a disorganized F-actin pattern with disrupted apical actin density and shank longitudinal cable direction/arrangement, indicating the novel role of RMD in F-actin polarity during tip growth. Consistent with this role, RMD localizes at the tip of the rice pollen tube, which is essential for pollen tube growth and polarity as well as F-actin organization. Furthermore, the direction and characteristics of the RMD-guided F-actin array positively regulate the deposition of cell wall components and the pattern and velocity of cytoplasmic streaming during rice pollen tube growth. Collectively, our results suggest that RMD is essential for the spatial regulation of pollen tube growth via modulating F-actin organization and array orientation in rice. This work provides insights into tip-focused cell growth and polarity.
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Affiliation(s)
- Gang Li
- University of Adelaide-Shanghai Jiao Tong University Joint Laboratory for Plant Science and Breeding, School of Agriculture, Food, and Wine, University of Adelaide, Waite Campus, Urrbrae, South Australia 5064, Australia
| | - Xiujuan Yang
- University of Adelaide-Shanghai Jiao Tong University Joint Laboratory for Plant Science and Breeding, School of Agriculture, Food, and Wine, University of Adelaide, Waite Campus, Urrbrae, South Australia 5064, Australia
| | - Xiaoqing Zhang
- Joint International Research Laboratory of Metabolic and Developmental Sciences, Shanghai Jiao Tong University-University of Adelaide Joint Centre for Agriculture and Health, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yu Song
- Joint International Research Laboratory of Metabolic and Developmental Sciences, Shanghai Jiao Tong University-University of Adelaide Joint Centre for Agriculture and Health, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Wanqi Liang
- Joint International Research Laboratory of Metabolic and Developmental Sciences, Shanghai Jiao Tong University-University of Adelaide Joint Centre for Agriculture and Health, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Dabing Zhang
- University of Adelaide-Shanghai Jiao Tong University Joint Laboratory for Plant Science and Breeding, School of Agriculture, Food, and Wine, University of Adelaide, Waite Campus, Urrbrae, South Australia 5064, Australia
- Joint International Research Laboratory of Metabolic and Developmental Sciences, Shanghai Jiao Tong University-University of Adelaide Joint Centre for Agriculture and Health, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
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35
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Mondal HA, Louis J, Archer L, Patel M, Nalam VJ, Sarowar S, Sivapalan V, Root DD, Shah J. Arabidopsis ACTIN-DEPOLYMERIZING FACTOR3 Is Required for Controlling Aphid Feeding from the Phloem. PLANT PHYSIOLOGY 2018; 176:879-890. [PMID: 29133373 PMCID: PMC5761796 DOI: 10.1104/pp.17.01438] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 11/09/2017] [Indexed: 05/09/2023]
Abstract
The actin cytoskeleton network has an important role in plant cell growth, division, and stress response. Actin-depolymerizing factors (ADFs) are a group of actin-binding proteins that contribute to reorganization of the actin network. Here, we show that the Arabidopsis (Arabidopsis thaliana) ADF3 is required in the phloem for controlling infestation by Myzus persicae Sülzer, commonly known as the green peach aphid (GPA), which is an important phloem sap-consuming pest of more than fifty plant families. In agreement with a role for the actin-depolymerizing function of ADF3 in defense against the GPA, we show that resistance in adf3 was restored by overexpression of the related ADF4 and the actin cytoskeleton destabilizers, cytochalasin D and latrunculin B. Electrical monitoring of the GPA feeding behavior indicates that the GPA stylets found sieve elements faster when feeding on the adf3 mutant compared to the wild-type plant. In addition, once they found the sieve elements, the GPA fed for a more prolonged period from sieve elements of adf3 compared to the wild-type plant. The longer feeding period correlated with an increase in fecundity and population size of the GPA and a parallel reduction in callose deposition in the adf3 mutant. The adf3-conferred susceptibility to GPA was overcome by expression of the ADF3 coding sequence from the phloem-specific SUC2 promoter, thus confirming the importance of ADF3 function in the phloem. We further demonstrate that the ADF3-dependent defense mechanism is linked to the transcriptional up-regulation of PHYTOALEXIN-DEFICIENT4, which is an important regulator of defenses against the GPA.
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Affiliation(s)
- Hossain A Mondal
- Department of Biological Sciences, University of North Texas, Denton, Texas 76203
- Uttar Banga Krishi Viswavidyalaya, Pundibari, Cooch Behar 736165, India
| | - Joe Louis
- Department of Biological Sciences, University of North Texas, Denton, Texas 76203
- Department of Entomology and Department of Biochemistry, University of Nebraska, Lincoln, Nebraska 68583
| | - Lani Archer
- Department of Biological Sciences, University of North Texas, Denton, Texas 76203
- BioDiscovery Institute, University of North Texas, Denton, Texas 76203
| | - Monika Patel
- Department of Biological Sciences, University of North Texas, Denton, Texas 76203
- BioDiscovery Institute, University of North Texas, Denton, Texas 76203
| | - Vamsi J Nalam
- Department of Biological Sciences, University of North Texas, Denton, Texas 76203
- Department of Biology, Indiana University-Purdue University, Fort Wayne, Indiana 46805
| | - Sujon Sarowar
- Department of Biological Sciences, University of North Texas, Denton, Texas 76203
| | - Vishala Sivapalan
- Department of Biological Sciences, University of North Texas, Denton, Texas 76203
| | - Douglas D Root
- Department of Biological Sciences, University of North Texas, Denton, Texas 76203
| | - Jyoti Shah
- Department of Biological Sciences, University of North Texas, Denton, Texas 76203
- BioDiscovery Institute, University of North Texas, Denton, Texas 76203
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36
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Szymanski D, Staiger CJ. The Actin Cytoskeleton: Functional Arrays for Cytoplasmic Organization and Cell Shape Control. PLANT PHYSIOLOGY 2018; 176:106-118. [PMID: 29192029 PMCID: PMC5761824 DOI: 10.1104/pp.17.01519] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 11/29/2017] [Indexed: 05/18/2023]
Abstract
Functionally distinct actin filament arrays cluster organelles and define cellular scale flow patterns for secretion.
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Affiliation(s)
- Dan Szymanski
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907
- Department of Agronomy, Purdue University, West Lafayette, Indiana 47907
| | - Christopher J Staiger
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907
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37
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Su H, Feng H, Chao X, Ding X, Nan Q, Wen C, Liu H, Xiang Y, Liu W. Fimbrins 4 and 5 Act Synergistically During Polarized Pollen Tube Growth to Ensure Fertility in Arabidopsis. PLANT & CELL PHYSIOLOGY 2017; 58:2006-2016. [PMID: 29036437 DOI: 10.1093/pcp/pcx138] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2017] [Accepted: 09/03/2017] [Indexed: 06/07/2023]
Abstract
The germination and polar growth of pollen are prerequisite for double fertilization in plants. The actin cytoskeleton and its binding proteins play pivotal roles in pollen germination and pollen tube growth. Two homologs of the actin-bundling protein fimbrin, AtFIM4 and AtFIM5, are highly expressed in pollen in Arabidopsis and can form distinct actin architectures in vitro, but how they co-operatively regulate pollen germination and pollen tube growth in vivo is largely unknown. In this study, we explored their functions during pollen germination and polar growth. Histochemical analysis demonstrated that AtFIM4 was expressed only after pollen grain hydration and, in the early stage of pollen tube growth, the expression level of AtFIM4 was low, indicating that it functions mainly during polarized tube growth, whereas AtFIM5 had high expression levels in both pollen grains and pollen tubes. Atfim4/atfim5 double mutant plants had fertility defects including reduced silique length and seed number, which were caused by severe defects in pollen germination and pollen tube growth. When the atfim4/atfim5 double mutant was complemented with the AtFIM5 protein, the polar growth of pollen tubes was fully rescued; however, AtFIM4 could only partially restore these defects. Fluorescence labeling showed that loss of function of both AtFIM4 and AtFIM5 decreased the extent of actin filament bundling throughout pollen tubes. Collectively, our results revealed that AtFIM4 acts co-ordinately with AtFIM5 to organize and maintain normal actin architecture in pollen grains and pollen tubes to fulfill double fertilization in plants.
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Affiliation(s)
- Hui Su
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, School of Life Sciences, Northwest University, Xi'an 710069, China
| | - Hualing Feng
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, School of Life Sciences, Northwest University, Xi'an 710069, China
| | - Xiaoting Chao
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, School of Life Sciences, Northwest University, Xi'an 710069, China
| | - Xia Ding
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, School of Life Sciences, Northwest University, Xi'an 710069, China
| | - Qiong Nan
- Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Chenxi Wen
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, School of Life Sciences, Northwest University, Xi'an 710069, China
| | | | - Yun Xiang
- Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Wenzhe Liu
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, School of Life Sciences, Northwest University, Xi'an 710069, China
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38
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Jiang Y, Wang J, Xie Y, Chen N, Huang S. ADF10 shapes the overall organization of apical actin filaments by promoting their turnover and ordering in pollen tubes. J Cell Sci 2017; 130:3988-4001. [PMID: 29061882 DOI: 10.1242/jcs.207738] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2017] [Accepted: 10/09/2017] [Indexed: 12/26/2022] Open
Abstract
Here, we show that Arabidopsis ADF10 plays an important role in shaping the overall organization of apical actin filaments by promoting their turnover and ordering. ADF10 severs and depolymerizes actin filaments in vitro and is distributed throughout the entire pollen tube. In adf10 mutants, severing and monomer dissociation events for apical actin filaments are reduced, and the apical actin structure extends further toward the tube base than in wild-type tubes. In particular, the percentage of apical actin filaments that form large angles to the tube growth axis is much higher in adf10 pollen tubes, and the actin filaments are more randomly distributed, implying that ADF10 promotes their ordering. Consistent with the role of apical actin filaments in physically restricting the movement of vesicles, the region in which apical vesicles accumulate is enlarged at the tip of adf10 pollen tubes. Both tipward and backward movements of small vesicles are altered within the growth domain of adf10 pollen tubes. Thus, our study suggests that ADF10 shapes the organization of apical actin filaments to regulate vesicle trafficking and pollen tube growth.
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Affiliation(s)
- Yuxiang Jiang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Juan Wang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yurong Xie
- Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Naizhi Chen
- Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Shanjin Huang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
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39
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Qu X, Zhang R, Zhang M, Diao M, Xue Y, Huang S. Organizational Innovation of Apical Actin Filaments Drives Rapid Pollen Tube Growth and Turning. MOLECULAR PLANT 2017; 10:930-947. [PMID: 28502709 DOI: 10.1016/j.molp.2017.05.002] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 04/15/2017] [Accepted: 05/01/2017] [Indexed: 06/07/2023]
Abstract
Polarized tip growth is a fundamental cellular process in many eukaryotes. In this study, we examined the dynamic restructuring of the actin cytoskeleton and its relationship to vesicle transport during pollen tip growth in Arabidopsis. We found that actin filaments originating from the apical membrane form a specialized structure consisting of longitudinally aligned actin bundles at the cortex and inner cytoplasmic filaments with a distinct distribution. Using actin-based pharmacological treatments and genetic mutants in combination with FRAP (fluorescence recovery after photobleaching) technology to visualize the transport of vesicles within the growth domain of pollen tubes, we demonstrated that cortical actin filaments facilitate tip-ward vesicle transport. We also discovered that the inner apical actin filaments prevent backward movement of vesicles, thus ensuring that sufficient vesicles accumulate at the pollen tube tip to support the rapid growth of the pollen tube. The combinatorial effect of cortical and internal apical actin filaments perfectly explains the generation of the inverted "V" cone-shaped vesicle distribution pattern at the pollen tube tip. When pollen tubes turn, apical actin filaments at the facing side undergo depolymerization and repolymerization to reorient the apical actin structure toward the new growth direction. This actin restructuring precedes vesicle accumulation and changes in tube morphology. Thus, our study provides new insights into the functional relationship between actin dynamics and vesicle transport during rapid and directional pollen tube growth.
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Affiliation(s)
- Xiaolu Qu
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Ruihui Zhang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Meng Zhang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China; Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Min Diao
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China; Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Yongbiao Xue
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101, China
| | - Shanjin Huang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China; Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
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40
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Yang X, Zhang Q, Zhao K, Luo Q, Bao S, Liu H, Men S. The Arabidopsis GPR1 Gene Negatively Affects Pollen Germination, Pollen Tube Growth, and Gametophyte Senescence. Int J Mol Sci 2017. [PMID: 28635622 PMCID: PMC5486124 DOI: 10.3390/ijms18061303] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Genes essential for gametophyte development and fertilization have been identified and studied in detail; however, genes that fine-tune these processes are largely unknown. Here, we characterized an unknown Arabidopsis gene, GTP-BINDING PROTEIN RELATED1 (GPR1). GPR1 is specifically expressed in ovule, pollen, and pollen tube. Enhanced green fluorescent protein-tagged GPR1 localizes to both nucleus and cytoplasm, and it also presents in punctate and ring-like structures. gpr1 mutants exhibit no defect in gametogenesis and seed setting, except that their pollen grains are pale in color. Scanning electron microscopy analyses revealed a normal patterned but thinner exine on gpr1 pollen surface. This may explain why gpr1 pollen grains are pale. We next examined whether GPR1 mutation affects post gametogenesis processes including pollen germination, pollen tube growth, and ovule senescence. We found that gpr1 pollen grains germinated earlier, and their pollen tubes elongated faster. Emasculation assay revealed that unfertilized gpr1 pistil expressed the senescence marker PBFN1:GUS (GUS: a reporter gene that encodes β-glucuronidase) one-day earlier than the wild type pistil. Consistently, ovules and pollen grains of gpr1 mutants showed lower viability than those of the wild type at 4 to 5 days post anthesis. Together, these data suggest that GPR1 functions as a negative regulator of pollen germination, pollen tube growth, and gametophyte senescence to fine-tune the fertilization process.
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Affiliation(s)
- Xiao Yang
- Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin 300071, China.
| | - Qinying Zhang
- Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin 300071, China.
| | - Kun Zhao
- Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin 300071, China.
| | - Qiong Luo
- Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin 300071, China.
| | - Shuguang Bao
- Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin 300071, China.
| | - Huabin Liu
- Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin 300071, China.
| | - Shuzhen Men
- Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin 300071, China.
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Abstract
The eukaryotic actin cytoskeleton is a highly dynamic framework that is involved in many biological processes, such as cell growth, division, morphology, and motility. G-actin polymerizes into microfilaments that associate into bundles, patches, and networks, which, in turn, organize into higher order structures that are fundamental for the course of important physiological events. Actin rings are an example for such higher order actin entities, but this term represents an actually diverse set of subcellular structures that are involved in various processes. This review especially sheds light on a crucial type of non-constricting ring-like actin networks, and categorizes them under the term 'actin fringe'. These 'actin fringes' are visualized as highly dynamic and yet steady structures in the tip of various polarized growing cells. The present comprehensive overview compares the actin fringe characteristics of rapidly elongating pollen tubes with several related actin arrays in other cell types of diverse species. The current state of knowledge about various actin fringe functions is summarized, and the key role of this structure in the polar growth process is discussed.
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Affiliation(s)
- Octavian O H Stephan
- Department of Biology, Friedrich-Alexander University of Erlangen-Nuremberg, Erlangen, Bavaria 91058, Germany
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Li S, Dong H, Pei W, Liu C, Zhang S, Sun T, Xue X, Ren H. LlFH1-mediated interaction between actin fringe and exocytic vesicles is involved in pollen tube tip growth. THE NEW PHYTOLOGIST 2017; 214:745-761. [PMID: 28092406 DOI: 10.1111/nph.14395] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 11/16/2016] [Indexed: 05/15/2023]
Abstract
Pollen tube tip growth is an extreme form of polarized cell growth, which requires polarized exocytosis based on a dynamic actin cytoskeleton. However, the molecular basis for the connection between actin filaments and exocytic vesicles is unclear. Here, we identified a Lilium longiflorum pollen-specific formin (LlFH1) and found that it localized at the apical vesicles and plasma membrane (PM). Overexpression of LlFH1 induced excessive actin cables in the tube tip region, and downregulation of LlFH1 eliminated the actin fringe. Fluorescence recovery after photobleaching (FRAP) analysis revealed that LlFH1-labeled exocytic vesicles exhibited an initial accumulation at the shoulder of the apex and coincided with the leading edge of the actin fringe. Time-lapse analysis suggested that nascent actin filaments followed the emergence of the apical vesicles, implying that LlFH1 at apical vesicles could initiate actin polymerization. Biochemical assays showed that LlFH1 FH1FH2 could nucleate actin polymerization, but then capped the actin filament at the barbed end and inhibited its elongation. However, in the presence of lily profilins, LlFH1 FH1FH2 could accelerate barbed-end actin elongation. In addition, LlFH1 FH1FH2 was able to bundle actin filaments. Thus, we propose that LlFH1 and profilin coordinate the interaction between the actin fringe and exocytic vesicle trafficking during pollen tube growth of lily.
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Affiliation(s)
- Shanwei Li
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education and College of Life Science, Beijing Normal University, Beijing, 100875, China
| | - Huaijian Dong
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education and College of Life Science, Beijing Normal University, Beijing, 100875, China
| | - Weike Pei
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education and College of Life Science, Beijing Normal University, Beijing, 100875, China
| | - Chaonan Liu
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education and College of Life Science, Beijing Normal University, Beijing, 100875, China
| | - Sha Zhang
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education and College of Life Science, Beijing Normal University, Beijing, 100875, China
| | - Tiantian Sun
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education and College of Life Science, Beijing Normal University, Beijing, 100875, China
| | - Xiuhua Xue
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education and College of Life Science, Beijing Normal University, Beijing, 100875, China
| | - Haiyun Ren
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education and College of Life Science, Beijing Normal University, Beijing, 100875, China
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Li Y, Tan X, Wang M, Li B, Zhao Y, Wu C, Rui Q, Wang J, Liu Z, Bao Y. Exocyst subunit SEC3A marks the germination site and is essential for pollen germination in Arabidopsis thaliana. Sci Rep 2017; 7:40279. [PMID: 28074928 PMCID: PMC5225640 DOI: 10.1038/srep40279] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 12/05/2016] [Indexed: 12/12/2022] Open
Abstract
Arabidopsis exocyst subunit SEC3A has been reported to participate in embryo development. Here we report that SEC3A is involved during pollen germination. A T-DNA insertion in SEC3A leads to an absolute, male-specific transmission defect that can be complemented by the expression of SEC3A coding sequence from the LAT52 promoter or SEC3A genomic DNA. No obvious abnormalities in the microgametogenesis are observed in the sec3a/SEC3A mutant, however, in vitro and in vivo pollen germination are defective. Further studies reveal that the callose, pectin, and cellulose are apparently not deposited at the germination site during pollen germination. SEC3A is expressed ubiquitously, including in pollen grains and pollen tubes. Notably, SEC3A-GFP fusion proteins are specifically recruited to the future pollen germination site. This particular localization pattern is independent of phosphatidylinositol 4,5-bisphosphate (PI-4,5P2), although SEC3-HIS fusion proteins are able to bind to several phosphoinositols in vitro. These results suggest that SEC3A plays an important role in the establishment of the polar site for pollen germination.
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Affiliation(s)
- Yan Li
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
| | - Xiaoyun Tan
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
| | - Mengru Wang
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
| | - Bingxuan Li
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
| | - Yanxue Zhao
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
| | - Chengyun Wu
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
| | - Qingchen Rui
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
| | - Junxia Wang
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
| | - Zhongyuan Liu
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
| | - Yiqun Bao
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
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Abstract
Underlying rapid and directional pollen tube growth is the active intracellular trafficking system that carries materials necessary for cell wall synthesis and membrane expansion to the expanding point of the pollen tube. The actin cytoskeleton has been shown to control various intracellular trafficking events in the pollen tube, but the underlying cellular and molecular mechanisms remain poorly understood. To better understand how the actin cytoskeleton is involved in the regulation of intracellular trafficking events, we need to establish assays to visualize and quantify the distribution and dynamics of organelles, vesicles, or secreted proteins. In this chapter, we introduce methods regarding the visualization and quantification of the distribution and dynamics of organelles or vesicles in pollen tubes.
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Ju Y, Guo L, Cai Q, Ma F, Zhu QY, Zhang Q. Arabidopsis JINGUBANG Is a Negative Regulator of Pollen Germination That Prevents Pollination in Moist Environments. THE PLANT CELL 2016; 28:2131-2146. [PMID: 27468890 PMCID: PMC5059805 DOI: 10.1105/tpc.16.00401] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 07/05/2016] [Accepted: 07/23/2016] [Indexed: 05/14/2023]
Abstract
The molecular mechanism of pollen germination and pollen tube growth has been revealed in detail during the last decade, while the mechanism that suspends pollen grains in a dormant state is largely unclear. Here, we identified the JINGUBANG (JGB) gene by screening pollen-specific genes for those that are unnecessary for pollen germination. We showed that the pollen of the jgb loss-of-function mutant exhibited hyperactive germination in sucrose-only medium and inside the anther, while this phenotype was rescued by the transgenic expression of JGB in jgb plants. JGB contains seven WD40 repeats and is highly conserved in flowering plants. Overexpression of JGB inhibits pollen germination. These results indicate that JGB is a novel negative regulator of pollen germination. In addition, we found that jasmonic acid (JA) abundance was significantly elevated in jgb pollen, while exogenous application of methyl jasmonate rescued the inhibition of pollen germination in plants overexpressing JGB Based on the molecular features of JGB and on the finding that it interacts with a known JA biosynthesis-related transcription factor, TCP4, we propose that JGB, together with TCP4, forms a regulatory complex that controls pollen JA synthesis, ensuring pollination in moist environments.
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Affiliation(s)
- Yan Ju
- Key Laboratory of Ministry of Education for Cell Proliferation and Differentiation, College of Life Sciences, Peking University, Beijing 100871, China
| | - Liang Guo
- Key Laboratory of Ministry of Education for Cell Proliferation and Differentiation, College of Life Sciences, Peking University, Beijing 100871, China
| | - Qiang Cai
- Key Laboratory of Ministry of Education for Cell Proliferation and Differentiation, College of Life Sciences, Peking University, Beijing 100871, China
| | - Fei Ma
- Key Laboratory of Ministry of Education for Cell Proliferation and Differentiation, College of Life Sciences, Peking University, Beijing 100871, China
| | - Qiao-Yun Zhu
- Key Laboratory of Ministry of Education for Cell Proliferation and Differentiation, College of Life Sciences, Peking University, Beijing 100871, China
| | - Quan Zhang
- Key Laboratory of Ministry of Education for Cell Proliferation and Differentiation, College of Life Sciences, Peking University, Beijing 100871, China
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46
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Ribosomal protein L18aB is required for both male gametophyte function and embryo development in Arabidopsis. Sci Rep 2016; 6:31195. [PMID: 27502163 PMCID: PMC4977502 DOI: 10.1038/srep31195] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 07/14/2016] [Indexed: 01/01/2023] Open
Abstract
Ribosomal proteins are involved in numerous essential cell activities in plants. However, the regulatory role in specific plant developmental processes has not yet been fully elucidated. Here we identified the new ribosomal protein L18aB, which is specifically involved in sexual reproduction and plays a critical role in male gametophyte development and embryo pattern formation. In rpl18aB mutant plants, the mature pollen grains can germinate normally, but their competitiveness for growing in the style is significantly reduced. More interestingly, RPL18aB is required in early embryogenesis. rpl18aB embryos displayed irregular cell division orientations in the early pro-embryo and arrested at the globular stage with possible, secondary pattern formation defects. Further investigations revealed that the polar transportation of auxin is disturbed in the rpl18aB mutant embryos, which may explain the observed failure in embryo pattern formation. The cell type-specific complementation of RPL18aB in rpl18aB was not able to recover the phenotype, indicating that RPL18aB may play an essential role in early cell fate determination. This work unravels a novel role in embryo development for a ribosomal protein, and provides insight into regulatory mechanism of early embryogenesis.
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47
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Mounet-Gilbert L, Dumont M, Ferrand C, Bournonville C, Monier A, Jorly J, Lemaire-Chamley M, Mori K, Atienza I, Hernould M, Stevens R, Lehner A, Mollet JC, Rothan C, Lerouge P, Baldet P. Two tomato GDP-D-mannose epimerase isoforms involved in ascorbate biosynthesis play specific roles in cell wall biosynthesis and development. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:4767-77. [PMID: 27382114 PMCID: PMC4973747 DOI: 10.1093/jxb/erw260] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
GDP-D-mannose epimerase (GME, EC 5.1.3.18) converts GDP-D-mannose to GDP-L-galactose, and is considered to be a central enzyme connecting the major ascorbate biosynthesis pathway to primary cell wall metabolism in higher plants. Our previous work demonstrated that GME is crucial for both ascorbate and cell wall biosynthesis in tomato. The aim of the present study was to investigate the respective role in ascorbate and cell wall biosynthesis of the two SlGME genes present in tomato by targeting each of them through an RNAi-silencing approach. Taken individually SlGME1 and SlGME2 allowed normal ascorbate accumulation in the leaf and fruits, thus suggesting the same function regarding ascorbate. However, SlGME1 and SlGME2 were shown to play distinct roles in cell wall biosynthesis, depending on the tissue considered. The RNAi-SlGME1 plants harbored small and poorly seeded fruits resulting from alterations of pollen development and of pollination process. In contrast, the RNAi-SlGME2 plants exhibited vegetative growth delay while fruits remained unaffected. Analysis of SlGME1- and SlGME2-silenced seeds and seedlings further showed that the dimerization state of pectin rhamnogalacturonan-II (RG-II) was altered only in the RNAi-SlGME2 lines. Taken together with the preferential expression of each SlGME gene in different tomato tissues, these results suggest sub-functionalization of SlGME1 and SlGME2 and their specialization for cell wall biosynthesis in specific tomato tissues.
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Affiliation(s)
- Louise Mounet-Gilbert
- Institut National de la Recherche Agronomique (INRA), Université de Bordeaux, Unité Mixte de Recherche 1332 Biologie du Fruit et Pathologie, CS20032, F-33882 Villenave d'Ornon Cedex, France
| | - Marie Dumont
- Normandy University, Université de Rouen, Laboratoire Glycobiologie et Matrice Extracellulaire Végétale, EA4358, IRIB, VASI, 76821 Mont-Saint-Aignan, France
| | - Carine Ferrand
- Institut National de la Recherche Agronomique (INRA), Université de Bordeaux, Unité Mixte de Recherche 1332 Biologie du Fruit et Pathologie, CS20032, F-33882 Villenave d'Ornon Cedex, France
| | - Céline Bournonville
- Institut National de la Recherche Agronomique (INRA), Université de Bordeaux, Unité Mixte de Recherche 1332 Biologie du Fruit et Pathologie, CS20032, F-33882 Villenave d'Ornon Cedex, France
| | - Antoine Monier
- Institut National de la Recherche Agronomique (INRA), Université de Bordeaux, Unité Mixte de Recherche 1332 Biologie du Fruit et Pathologie, CS20032, F-33882 Villenave d'Ornon Cedex, France
| | - Joana Jorly
- Institut National de la Recherche Agronomique (INRA), Université de Bordeaux, Unité Mixte de Recherche 1332 Biologie du Fruit et Pathologie, CS20032, F-33882 Villenave d'Ornon Cedex, France
| | - Martine Lemaire-Chamley
- Institut National de la Recherche Agronomique (INRA), Université de Bordeaux, Unité Mixte de Recherche 1332 Biologie du Fruit et Pathologie, CS20032, F-33882 Villenave d'Ornon Cedex, France
| | - Kentaro Mori
- Institut National de la Recherche Agronomique (INRA), Université de Bordeaux, Unité Mixte de Recherche 1332 Biologie du Fruit et Pathologie, CS20032, F-33882 Villenave d'Ornon Cedex, France
| | - Isabelle Atienza
- Institut National de la Recherche Agronomique (INRA), Université de Bordeaux, Unité Mixte de Recherche 1332 Biologie du Fruit et Pathologie, CS20032, F-33882 Villenave d'Ornon Cedex, France
| | - Michel Hernould
- Institut National de la Recherche Agronomique (INRA), Université de Bordeaux, Unité Mixte de Recherche 1332 Biologie du Fruit et Pathologie, CS20032, F-33882 Villenave d'Ornon Cedex, France
| | - Rebecca Stevens
- Institut National de la Recherche Agronomique (INRA), Unité de Recherche 1052 Génétique et Amélioration des Fruits et Légumes, Domaine Saint Maurice, 67, Allée des Chênes, CS 60094 F-84143 Montfavet Cedex, France
| | - Arnaud Lehner
- Normandy University, Université de Rouen, Laboratoire Glycobiologie et Matrice Extracellulaire Végétale, EA4358, IRIB, VASI, 76821 Mont-Saint-Aignan, France
| | - Jean Claude Mollet
- Normandy University, Université de Rouen, Laboratoire Glycobiologie et Matrice Extracellulaire Végétale, EA4358, IRIB, VASI, 76821 Mont-Saint-Aignan, France
| | - Christophe Rothan
- Institut National de la Recherche Agronomique (INRA), Université de Bordeaux, Unité Mixte de Recherche 1332 Biologie du Fruit et Pathologie, CS20032, F-33882 Villenave d'Ornon Cedex, France
| | - Patrice Lerouge
- Normandy University, Université de Rouen, Laboratoire Glycobiologie et Matrice Extracellulaire Végétale, EA4358, IRIB, VASI, 76821 Mont-Saint-Aignan, France
| | - Pierre Baldet
- Institut National de la Recherche Agronomique (INRA), Université de Bordeaux, Unité Mixte de Recherche 1332 Biologie du Fruit et Pathologie, CS20032, F-33882 Villenave d'Ornon Cedex, France
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48
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Zhang S, Liu C, Wang J, Ren Z, Staiger CJ, Ren H. A Processive Arabidopsis Formin Modulates Actin Filament Dynamics in Association with Profilin. MOLECULAR PLANT 2016; 9:900-10. [PMID: 26996265 DOI: 10.1016/j.molp.2016.03.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 02/28/2016] [Accepted: 03/04/2016] [Indexed: 05/08/2023]
Abstract
Formins are conserved regulators of actin cytoskeletal organization and dynamics that have been implicated to be important for cell division and cell polarity. The mechanism by which diverse formins regulate actin dynamics in plants is still not well understood. Using in vitro single-molecule imaging technology, we directly observed that the FH1-FH2 domain of an Arabidopsis thaliana formin, AtFH14, processively attaches to the barbed end of actin filaments as a dimer and slows their elongation rate by 90%. The attachment persistence of FH1-FH2 is concentration dependent. Furthermore, by use of the triple-color total internal reflection fluorescence microscopy, we found that ABP29, a barbed-end capping protein, competes with FH1-FH2 at the filament barbed end, where its binding is mutually exclusive with AtFH14. In the presence of different plant profilin isoforms, FH1-FH2 enhances filament elongation rates from about 10 to 42 times. Filaments buckle when FH1-FH2 is anchored specifically to cover slides, further indicating that AtFH14 moves processively on the elongating barbed end. At high concentration, AtFH14 bundles actin filaments randomly into antiparallel or parallel spindle-like structures; however, the FH1-FH2-mediated bundles become thinner and longer in the presence of plant profilins. This is the direct demonstration of a processive formin from plants. Our results also illuminate the molecular mechanism of AtFH14 in regulating actin dynamics via association with profilin.
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Affiliation(s)
- Sha Zhang
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Science, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Chang Liu
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Science, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Jiaojiao Wang
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Science, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Zhanhong Ren
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Science, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Christopher J Staiger
- Department of Biological Sciences, Purdue University, Hansen Life Sciences Research Building, West Lafayette, IN 47907-2064, USA
| | - Haiyun Ren
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Science, Beijing Normal University, Beijing 100875, People's Republic of China.
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49
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Zhang M, Zhang R, Qu X, Huang S. Arabidopsis FIM5 decorates apical actin filaments and regulates their organization in the pollen tube. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:3407-17. [PMID: 27117336 PMCID: PMC4892729 DOI: 10.1093/jxb/erw160] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The actin cytoskeleton is increasingly recognized as a major regulator of pollen tube growth. Actin filaments have distinct distribution patterns and dynamic properties within different regions of the pollen tube. Apical actin filaments are highly dynamic and crucial for pollen tube growth. However, how apical actin filaments are generated and properly constructed remains an open question. Here we showed that Arabidopsis fimbrin5 (FIM5) decorates filamentous structures throughout the entire tube but is apically concentrated. Apical actin structures are disorganized to different degrees in the pollen tubes of fim5 loss-of-function mutants. Further observations suggest that apical actin structures are not constructed properly because apical actin filaments cannot be maintained at the cortex of fim5 pollen tubes. Actin filaments appeared to be more curved in fim5 pollen tubes and this was confirmed by measurements showing that the convolutedness and the rate of change of convolutedness of actin filaments was significantly increased in fim5 pollen tubes. This suggests that the rigidity of the actin filaments may be compromised in fim5 pollen tubes. Further, the apical cell wall composition is altered, implying that tip-directed vesicle trafficking events are impaired in fim5 pollen tubes. Thus, we found that FIM5 decorates apical actin filaments and regulates their organization in order to drive polarized pollen tube growth.
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Affiliation(s)
- Meng Zhang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany Chinese Academy of Sciences, Beijing 100093 China University of Chinese Academy of Sciences, Beijing 100049 China
| | - Ruihui Zhang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany Chinese Academy of Sciences, Beijing 100093 China University of Chinese Academy of Sciences, Beijing 100049 China
| | - Xiaolu Qu
- Center for Plant Biology, School of Life Sciences, Tsinghua University Beijing 100084, China Tsinghua-Peking Joint Center for Life Sciences, Beijing 100084 China
| | - Shanjin Huang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany Chinese Academy of Sciences, Beijing 100093 China Center for Plant Biology, School of Life Sciences, Tsinghua University Beijing 100084, China National Center for Plant Gene Research, Beijing 100101 China
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50
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Borassi C, Sede AR, Mecchia MA, Salgado Salter JD, Marzol E, Muschietti JP, Estevez JM. An update on cell surface proteins containing extensin-motifs. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:477-87. [PMID: 26475923 DOI: 10.1093/jxb/erv455] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
In recent years it has become clear that there are several molecular links that interconnect the plant cell surface continuum, which is highly important in many biological processes such as plant growth, development, and interaction with the environment. The plant cell surface continuum can be defined as the space that contains and interlinks the cell wall, plasma membrane and cytoskeleton compartments. In this review, we provide an updated view of cell surface proteins that include modular domains with an extensin (EXT)-motif followed by a cytoplasmic kinase-like domain, known as PERKs (for proline-rich extensin-like receptor kinases); with an EXT-motif and an actin binding domain, known as formins; and with extracellular hybrid-EXTs. We focus our attention on the EXT-motifs with the short sequence Ser-Pro(3-5), which is found in several different protein contexts within the same extracellular space, highlighting a putative conserved structural and functional role. A closer understanding of the dynamic regulation of plant cell surface continuum and its relationship with the downstream signalling cascade is a crucial forthcoming challenge.
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Affiliation(s)
- Cecilia Borassi
- Fundación Instituto Leloir, IIBBA-CONICET, Av. Patricias Argentinas 435, Buenos Aires, C1405BWE, Argentina
| | - Ana R Sede
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Dr. Héctor Torres (INGEBI-CONICET), Vuelta de Obligado 2490, Buenos Aires, C1428ADN, Argentina
| | - Martin A Mecchia
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Dr. Héctor Torres (INGEBI-CONICET), Vuelta de Obligado 2490, Buenos Aires, C1428ADN, Argentina
| | - Juan D Salgado Salter
- Fundación Instituto Leloir, IIBBA-CONICET, Av. Patricias Argentinas 435, Buenos Aires, C1405BWE, Argentina
| | - Eliana Marzol
- Fundación Instituto Leloir, IIBBA-CONICET, Av. Patricias Argentinas 435, Buenos Aires, C1405BWE, Argentina
| | - Jorge P Muschietti
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Dr. Héctor Torres (INGEBI-CONICET), Vuelta de Obligado 2490, Buenos Aires, C1428ADN, Argentina. Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Pabellón II, C1428EGA Buenos Aires, Argentina.
| | - Jose M Estevez
- Fundación Instituto Leloir, IIBBA-CONICET, Av. Patricias Argentinas 435, Buenos Aires, C1405BWE, Argentina.
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