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Liu L, Wang Y, Cao W, Yang L, Zhang C, Yuan L, Wang D, Wang W, Zhang H, Schiefelbein J, Yu F, An L. TRANSPARENT TESTA GLABRA2 defines trichome cell shape by modulating actin cytoskeleton in Arabidopsis thaliana. PLANT PHYSIOLOGY 2024; 195:1256-1276. [PMID: 38391271 DOI: 10.1093/plphys/kiae091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 01/11/2024] [Accepted: 01/17/2024] [Indexed: 02/24/2024]
Abstract
The Arabidopsis (Arabidopsis thaliana) TRANSPARENT TESTA GLABRA2 (TTG2) gene encodes a WRKY transcription factor that regulates a range of development events like trichome, seed coat, and atrichoblast formation. Loss-of-function of TTG2 was previously shown to reduce or eliminate trichome specification and branching. Here, we report the identification of an allele of TTG2, ttg2-6. In contrast to the ttg2 mutants described before, ttg2-6 displayed unique trichome phenotypes. Some ttg2-6 mutant trichomes were hyper-branched, whereas others were hypo-branched, distorted, or clustered. Further, we found that in addition to specifically activating R3 MYB transcription factor TRIPTYCHON (TRY) to modulate trichome specification, TTG2 also integrated cytoskeletal signaling to regulate trichome morphogenesis. The ttg2-6 trichomes displayed aberrant cortical microtubules (cMTs) and actin filaments (F-actin) configurations. Moreover, genetic and biochemical analyses showed that TTG2 could directly bind to the promoter and regulate the expression of BRICK1 (BRK1), which encodes a subunit of the actin nucleation promoting complex suppressor of cyclic AMP repressor (SCAR)/Wiskott-Aldrich syndrome protein family verprolin homologous protein (WAVE). Collectively, taking advantage of ttg2-6, we uncovered a function for TTG2 in facilitating cMTs and F-actin cytoskeleton-dependent trichome development, providing insight into cellular signaling events downstream of the core transcriptional regulation during trichome development in Arabidopsis.
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Affiliation(s)
- Lu Liu
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Yali Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Weihua Cao
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Lan Yang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Chi Zhang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Lanxin Yuan
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Dan Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Wenjia Wang
- CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Hongchang Zhang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - John Schiefelbein
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Fei Yu
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Lijun An
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China
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Moser M, Groves NR, Meier I. Plant KASH proteins SINE1 and SINE2 have synergistic and antagonistic interactions with actin-branching and actin-bundling factors. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:73-87. [PMID: 37819623 DOI: 10.1093/jxb/erad400] [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: 07/07/2023] [Accepted: 10/09/2023] [Indexed: 10/13/2023]
Abstract
Linker of nucleoskeleton and cytoskeleton (LINC) complexes consist of outer nuclear membrane KASH proteins, interacting in the nuclear envelope lumen with inner nuclear membrane SUN proteins and connecting the nucleus and cytoskeleton. The paralogous Arabidopsis KASH proteins SINE1 and SINE2 function during stomatal dynamics induced by light-dark transitions and abscisic acid (ABA), which requires F-actin reorganization. SINE2 influences actin depolymerization and SINE1 actin repolymerization. The actin-related protein 2/3 (ARP2/3) complex, an actin nucleator, and the plant actin-bundling and -stabilizing factor SCAB1 are involved in stomatal aperture control. Here, we have tested the genetic interaction of SINE1 and SINE2 with SCAB1 and the ARP2/3 complex. We show that SINE1 and the ARP2/3 complex function in the same pathway during ABA-induced stomatal closure, while SINE2 and the ARP2/3 complex play opposing roles. The actin repolymerization defect observed in sine1-1 is partially rescued in scab1-2 sine1-1, while SINE2 is epistatic to SCAB1. In addition, SINE1 and ARP2/3 act synergistically in lateral root development. The absence of SINE2 renders trichome development independent of the ARP2/3 complex. Together, these data reveal complex and differential interactions of the two KASH proteins with the actin-remodeling apparatus and add evidence to the proposed differential role of SINE1 and SINE2 in actin dynamics.
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Affiliation(s)
- Morgan Moser
- Department of Molecular Genetics, The Ohio State University, Columbus, OH, USA
| | - Norman R Groves
- Department of Molecular Genetics, The Ohio State University, Columbus, OH, USA
- Center for Applied Plant Sciences, The Ohio State University, Columbus, OH, USA
| | - Iris Meier
- Department of Molecular Genetics, The Ohio State University, Columbus, OH, USA
- Center for Applied Plant Sciences, The Ohio State University, Columbus, OH, USA
- Center for RNA Biology, The Ohio State University, Columbus, OH, USA
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3
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Zhang X, Wang Q, Wu J, Qi M, Zhang C, Huang Y, Wang G, Wang H, Tian J, Yu Y, Chen D, Li Y, Wang D, Zhang Y, Xue Y, Kong Z. A legume kinesin controls vacuole morphogenesis for rhizobia endosymbiosis. NATURE PLANTS 2022; 8:1275-1288. [PMID: 36316454 DOI: 10.1038/s41477-022-01261-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 09/09/2022] [Indexed: 06/16/2023]
Abstract
Symbioses between legumes and rhizobia require establishment of the plant-derived symbiosome membrane, which surrounds the rhizobia and accommodates the symbionts by providing an interface for nutrient and signal exchange. The host cytoskeleton and endomembrane trafficking systems play central roles in the formation of a functional symbiotic interface for rhizobia endosymbiosis; however, the underlying mechanisms remain largely unknown. Here we demonstrate that the nodulation-specific kinesin-like calmodulin-binding protein (nKCBP), a plant-specific microtubule-based kinesin motor, controls central vacuole morphogenesis in symbiotic cells in Medicago truncatula. Phylogenetic analysis further indicated that nKCBP duplication occurs solely in legumes of the clade that form symbiosomes. Knockout of nKCBP results in central vacuole deficiency, defective symbiosomes and abolished nitrogen fixation. nKCBP decorates linear particles along microtubules, and crosslinks microtubules with the actin cytoskeleton, to control central vacuole formation by modulating vacuolar vesicle fusion in symbiotic cells. Together, our findings reveal that rhizobia co-opted nKCBP to achieve symbiotic interface formation by regulating cytoskeletal assembly and central vacuole morphogenesis during nodule development.
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Affiliation(s)
- Xiaxia Zhang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, China
| | - Qi Wang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, China
| | - Jingxia Wu
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, China
| | - Meifang Qi
- State Key Laboratory of Plant Molecular Genetics, Center for Excellence in Molecular Plant Science, Chinese Academy of Sciences, Shanghai, China
| | - Chen Zhang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, China
| | - Yige Huang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, China
| | - Guangda Wang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, China
| | - Huan Wang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, China
| | - Juan Tian
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, China
| | - Yanjun Yu
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, China
| | - Dasong Chen
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Youguo Li
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Dong Wang
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, MA, USA
| | - Yijing Zhang
- State Key Laboratory of Plant Molecular Genetics, Center for Excellence in Molecular Plant Science, Chinese Academy of Sciences, Shanghai, China
| | - Yongbiao Xue
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Zhaosheng Kong
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, China.
- Houji Laboratory in Shanxi Province, Academy of Agronomy, Shanxi Agricultural University, Taiyuan, China.
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Chun JI, Kim SM, Jeong NR, Kim SH, Jung C, Kang JH. Tomato ARPC1 regulates trichome morphology and density and terpene biosynthesis. PLANTA 2022; 256:38. [PMID: 35821288 DOI: 10.1007/s00425-022-03955-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 06/29/2022] [Indexed: 06/15/2023]
Abstract
Based on transcriptomic analysis of wild-type and mutant tomato plants, ARPC1 was found to be important for trichome formation and development and it plays a key role in terpene synthesis. Trichomes are protruding epidermal cells in plant species. They function as the first defense layer against biotic and abiotic stresses. Despite the essential role of tomato trichomes in defense against herbivores, the understanding of their development is still incomplete. Therefore, the aim of this study was to identify genes involved in trichome formation and morphology and terpene synthesis, using transcriptomic techniques. To achieve this, we examined leaf morphology and compared the expression levels of some putative genes involved in trichome formation between wild-type (WT) and hairless-3 (hl-3) tomato mutant. The hl-3 plants displayed swollen and distorted trichomes and reduced trichome density (type I and IV) and terpene synthesis compared with that of the WT plants. Gene expression analysis showed that Actin-Related Protein Component1 (ARPC1) was expressed more highly in the WT than in the hl-3 mutant, indicating its critical role in trichome morphology and density. Additionally, the expression of MYC1 and several terpene synthase genes (TPS9, 12, 20), which are involved in type VI trichome initiation and terpene synthesis, was lower in the hl-3 mutant than in the WT plants. Moreover, transformation of the hl-3 mutant with WT ARPC1 restored normal trichome structure and density, and terpene synthesis. Structural and amino acid sequence analysis showed that there was a missplicing mutation in the hl-3 mutant, which was responsible for the abnormal trichome structure and density, and impaired terpene synthesis. Overall, the findings of this study demonstrated that ARPC1 is involved in regulating trichome structure and terpene synthesis in tomato.
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Affiliation(s)
- Jae-In Chun
- Department of Agriculture, Forestry and Bioresources and Integrated Major in Global Smart Farm, College of Agriculture and Life Sciences, Seoul National University, Seoul, 08826, Republic of Korea
- Institutes of Green-Bio Science and Technology, Seoul National University, Seoul, PyeongChang, 25354, Republic of Korea
| | - Seong-Min Kim
- Department of Agriculture, Forestry and Bioresources and Integrated Major in Global Smart Farm, College of Agriculture and Life Sciences, Seoul National University, Seoul, 08826, Republic of Korea
- Institutes of Green-Bio Science and Technology, Seoul National University, Seoul, PyeongChang, 25354, Republic of Korea
| | - Na-Rae Jeong
- Department of International Agricultural Technology, Seoul National University, Seoul, PyeongChang, 25354, Republic of Korea
- Department of Internal Medicine, Seoul National University Hospital, Seoul, Republic of Korea
| | - Sang Hee Kim
- Division of Applied Life Science (BK21 Four Program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, 52828, Republic of Korea
| | - Choonkyun Jung
- Department of Agriculture, Forestry and Bioresources and Integrated Major in Global Smart Farm, College of Agriculture and Life Sciences, Seoul National University, Seoul, 08826, Republic of Korea
- Institutes of Green-Bio Science and Technology, Seoul National University, Seoul, PyeongChang, 25354, Republic of Korea
- Department of International Agricultural Technology, Seoul National University, Seoul, PyeongChang, 25354, Republic of Korea
| | - Jin-Ho Kang
- Department of Agriculture, Forestry and Bioresources and Integrated Major in Global Smart Farm, College of Agriculture and Life Sciences, Seoul National University, Seoul, 08826, Republic of Korea.
- Institutes of Green-Bio Science and Technology, Seoul National University, Seoul, PyeongChang, 25354, Republic of Korea.
- Department of International Agricultural Technology, Seoul National University, Seoul, PyeongChang, 25354, Republic of Korea.
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Wang H, Umer MJ, Liu F, Cai X, Zheng J, Xu Y, Hou Y, Zhou Z. Genome-Wide Identification and Characterization of CPR5 Genes in Gossypium Reveals Their Potential Role in Trichome Development. Front Genet 2022; 13:921096. [PMID: 35754813 PMCID: PMC9213653 DOI: 10.3389/fgene.2022.921096] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 05/10/2022] [Indexed: 01/18/2023] Open
Abstract
Trichomes protect plants against insects, microbes, herbivores, and abiotic damages and assist seed dispersal. The function of CPR5 genes have been found to be involved in the trichome development but the research on the underlying genetic and molecular mechanisms are extremely limited. Herein, genome wide identification and characterization of CPR5 genes was performed. In total, 26 CPR5 family members were identified in Gossypium species. Phylogenetic analysis, structural characteristics, and synteny analysis of CPR5s showed the conserved evolution relationships of CPR5. The promoter analysis of CPR5 genes revealed hormone, stress, and development-related cis-elements. Gene ontology (GO) enrichment analysis showed that the CPR5 genes were largely related to biological regulation, developmental process, multicellular organismal process. Protein-protein interaction analysis predicted several trichome development related proteins (SIM, LGO, and GRL) directly interacting with CPR5 genes. Further, nine putative Gossypium-miRNAs were also identified, targeting Gossypium CPR5 genes. RNA-Seq data of G. arboreum (with trichomes) and G. herbaceum (with no trichomes) was used to perform the co-expression network analysis. GheCPR5.1 was identified as a hub gene in a co-expression network analysis. RT-qPCR of GheCPR5.1 gene in different tissues suggests that this gene has higher expressions in the petiole and might be a key candidate involved in the trichome development. Virus induced gene silencing of GheCPR5.1 (Ghe02G17590) confirms its role in trichome development and elongation. Current results provide proofs of the possible role of CPR5 genes and provide preliminary information for further studies of GheCPR5.1 functions in trichome development.
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Affiliation(s)
- Heng Wang
- State Key Laboratory of Cotton Biology /Institute of Cotton Research, Chinese Academy of Agricultural Science, Anyang, China
| | - Muhammad Jawad Umer
- State Key Laboratory of Cotton Biology /Institute of Cotton Research, Chinese Academy of Agricultural Science, Anyang, China
| | - Fang Liu
- State Key Laboratory of Cotton Biology /Institute of Cotton Research, Chinese Academy of Agricultural Science, Anyang, China.,School of Agricultural Sciences, Zhengzhou University, Zhengzhou, China.,National Nanfan Research Institute (Sanya), Chinese Academy of Agriculture Sciences, Sanya, China
| | - Xiaoyan Cai
- State Key Laboratory of Cotton Biology /Institute of Cotton Research, Chinese Academy of Agricultural Science, Anyang, China
| | - Jie Zheng
- State Key Laboratory of Cotton Biology /Institute of Cotton Research, Chinese Academy of Agricultural Science, Anyang, China.,National Nanfan Research Institute (Sanya), Chinese Academy of Agriculture Sciences, Sanya, China.,Hainan Yazhou Bay Seed Laboratory, Sanya, China
| | - Yanchao Xu
- State Key Laboratory of Cotton Biology /Institute of Cotton Research, Chinese Academy of Agricultural Science, Anyang, China.,College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Yuqing Hou
- State Key Laboratory of Cotton Biology /Institute of Cotton Research, Chinese Academy of Agricultural Science, Anyang, China
| | - Zhongli Zhou
- State Key Laboratory of Cotton Biology /Institute of Cotton Research, Chinese Academy of Agricultural Science, Anyang, China
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6
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Zuch DT, Doyle SM, Majda M, Smith RS, Robert S, Torii KU. Cell biology of the leaf epidermis: Fate specification, morphogenesis, and coordination. THE PLANT CELL 2022; 34:209-227. [PMID: 34623438 PMCID: PMC8774078 DOI: 10.1093/plcell/koab250] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 09/18/2021] [Indexed: 05/02/2023]
Abstract
As the outermost layer of plants, the epidermis serves as a critical interface between plants and the environment. During leaf development, the differentiation of specialized epidermal cell types, including stomatal guard cells, pavement cells, and trichomes, occurs simultaneously, each providing unique and pivotal functions for plant growth and survival. Decades of molecular-genetic and physiological studies have unraveled key players and hormone signaling specifying epidermal differentiation. However, most studies focus on only one cell type at a time, and how these distinct cell types coordinate as a unit is far from well-comprehended. Here we provide a review on the current knowledge of regulatory mechanisms underpinning the fate specification, differentiation, morphogenesis, and positioning of these specialized cell types. Emphasis is given to their shared developmental origins, fate flexibility, as well as cell cycle and hormonal controls. Furthermore, we discuss computational modeling approaches to integrate how mechanical properties of individual epidermal cell types and entire tissue/organ properties mutually influence each other. We hope to illuminate the underlying mechanisms coordinating the cell differentiation that ultimately generate a functional leaf epidermis.
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Affiliation(s)
| | | | - Mateusz Majda
- Department of Computational and Systems Biology, John Innes Centre, Norwich NR4 7UH, UK
| | - Richard S Smith
- Department of Computational and Systems Biology, John Innes Centre, Norwich NR4 7UH, UK
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Sharma V, Clark AJ, Kawashima T. Insights into the molecular evolution of fertilization mechanism in land plants. PLANT REPRODUCTION 2021; 34:353-364. [PMID: 34061252 DOI: 10.1007/s00497-021-00414-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 05/14/2021] [Indexed: 05/27/2023]
Abstract
Comparative genetics and genomics among green plants, including algae, provide deep insights into the evolution of land plant sexual reproduction. Land plants have evolved successive changes during their conquest of the land and innovations in sexual reproduction have played a major role in their terrestrialization. Recent years have seen many revealing dissections of the molecular mechanisms of sexual reproduction and much new genomics data from the land plant lineage, including early diverging land plants, as well as algae. This new knowledge is being integrated to further understand how sexual reproduction in land plants evolved, identifying highly conserved factors and pathways, but also molecular changes that underpinned the emergence of new modes of sexual reproduction. Here, we review recent advances in the knowledge of land plant sexual reproduction from an evolutionary perspective and also revisit the evolution of angiosperm double fertilization.
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Affiliation(s)
- Vijyesh Sharma
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY, 40546, USA
| | - Anthony J Clark
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY, 40546, USA
| | - Tomokazu Kawashima
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY, 40546, USA.
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8
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Chin S, Kwon T, Khan BR, Sparks JA, Mallery EL, Szymanski DB, Blancaflor EB. Spatial and temporal localization of SPIRRIG and WAVE/SCAR reveal roles for these proteins in actin-mediated root hair development. THE PLANT CELL 2021; 33:2131-2148. [PMID: 33881536 PMCID: PMC8364238 DOI: 10.1093/plcell/koab115] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 04/15/2021] [Indexed: 05/31/2023]
Abstract
Root hairs are single-cell protrusions that enable roots to optimize nutrient and water acquisition. These structures attain their tubular shapes by confining growth to the cell apex, a process called tip growth. The actin cytoskeleton and endomembrane systems are essential for tip growth; however, little is known about how these cellular components coordinate their activities during this process. Here, we show that SPIRRIG (SPI), a beige and Chediak Higashi domain-containing protein involved in membrane trafficking, and BRK1 and SCAR2, subunits of the WAVE/SCAR (W/SC) actin nucleating promoting complex, display polarized localizations in Arabidopsis thaliana root hairs during distinct developmental stages. SPI accumulates at the root hair apex via post-Golgi compartments and positively regulates tip growth by maintaining tip-focused vesicle secretion and filamentous-actin integrity. BRK1 and SCAR2 on the other hand, mark the root hair initiation domain to specify the position of root hair emergence. Consistent with the localization data, tip growth was reduced in spi and the position of root hair emergence was disrupted in brk1 and scar1234. BRK1 depletion coincided with SPI accumulation as root hairs transitioned from initiation to tip growth. Taken together, our work uncovers a role for SPI in facilitating actin-dependent root hair development in Arabidopsis through pathways that might intersect with W/SC.
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Affiliation(s)
- Sabrina Chin
- Noble Research Institute LLC, 2510 Sam Noble Parkway, Ardmore, Oklahoma 73401, USA
| | - Taegun Kwon
- Noble Research Institute LLC, 2510 Sam Noble Parkway, Ardmore, Oklahoma 73401, USA
| | - Bibi Rafeiza Khan
- Noble Research Institute LLC, 2510 Sam Noble Parkway, Ardmore, Oklahoma 73401, USA
| | - J. Alan Sparks
- Noble Research Institute LLC, 2510 Sam Noble Parkway, Ardmore, Oklahoma 73401, USA
| | - Eileen L. Mallery
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907, USA
| | - Daniel B. Szymanski
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907, USA
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907, USA
| | - Elison B. Blancaflor
- Noble Research Institute LLC, 2510 Sam Noble Parkway, Ardmore, Oklahoma 73401, USA
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9
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Nie WF, Wang J. Actin-Related Protein 4 Interacts with PIE1 and Regulates Gene Expression in Arabidopsis. Genes (Basel) 2021; 12:genes12040520. [PMID: 33918349 PMCID: PMC8066076 DOI: 10.3390/genes12040520] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 03/25/2021] [Accepted: 03/29/2021] [Indexed: 12/19/2022] Open
Abstract
As essential structural components of ATP-dependent chromatin-remodeling complex, the nucleolus-localized actin-related proteins (ARPs) play critical roles in many biological processes. Among them, ARP4 is identified as an integral subunit of chromatin remodeling complex SWR1, which is conserved in yeast, humans and plants. It was shown that RNAi mediated knock-down of Arabidopsisthaliana ARP4 (AtARP4) could affect plant development, specifically, leading to early flowering. However, so far, little is known about how ARP4 functions in the SWR1 complex in plant. Here, we identified a loss-of-function mutant of AtARP4 with a single nucleotide change from glycine to arginine, which had significantly smaller leaf size. The results from the split luciferase complementation imaging (LCI) and yeast two hybrid (Y2H) assays confirmed its physical interaction with the scaffold and catalytic subunit of SWR1 complex, photoperiod-independent early flowering 1 (PIE1). Furthermore, mutation of AtARP4 caused altered transcription response of hundreds of genes, in which the number of up-regulated differentially expressed genes (DEGs) was much larger than those down-regulated. Although most DEGs in atarp4 are related to plant defense and response to hormones such as salicylic acid, overall, it has less overlapping with other swr1 mutants and the hta9 hta11 double-mutant. In conclusion, our results reveal that AtARP4 is important for plant growth and such an effect is likely attributed to its repression on gene expression, typically at defense-related loci, thus providing some evidence for the coordination of plant growth and defense, while the regulatory patterns and mechanisms are distinctive from other SWR1 complex components.
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10
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Xie Q, Gao Y, Li J, Yang Q, Qu X, Li H, Zhang J, Wang T, Ye Z, Yang C. The HD-Zip IV transcription factor SlHDZIV8 controls multicellular trichome morphology by regulating the expression of Hairless-2. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:7132-7145. [PMID: 32930788 DOI: 10.1093/jxb/eraa428] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 09/12/2020] [Indexed: 06/11/2023]
Abstract
Trichomes are specialized epidermal appendages that serve as excellent models to study cell morphogenesis. Although the molecular mechanism underlying trichome morphogenesis in Arabidopsis has been well characterized, most of the regulators essential for multicellular trichome morphology remain unknown in tomato. In this study, we determined that the recessive hairless-2 (hl-2) mutation in tomato causes severe distortion of all trichome types, along with increased stem fragility. Using map-based cloning, we found that the hl-2 phenotype was associated with a 100 bp insertion in the coding region of Nck-associated protein 1, a component of the SCAR/WAVE complex. Direct protein-protein interaction was detected between Hl-2 and Hl (SRA1, specifically Rac1-associated protein) using yeast two-hybrid and co-immunoprecipitation assays, suggesting that these proteins may work together during trichome formation. In addition, knock-down of a HD-Zip IV transcription factor, HDZIPIV8, distorted trichomes similar to the hl-2 mutant. HDZIPIV8 regulates the expression of Hl-2 by binding to the L1-box in the Hl-2 promoter region, and is involved in organizing actin filaments. The brittleness of hl-2 stems was found to result from decreased cellulose content. Taken together, these findings suggest that the Hl-2 gene plays an important role in controlling multicellular trichome morphogenesis and mechanical properties of stems in tomato plants.
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Affiliation(s)
- Qingmin Xie
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
| | - Yanna Gao
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
| | - Jing Li
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
| | - Qihong Yang
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
| | - Xiaolu Qu
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
| | - Hanxia Li
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
| | - Junhong Zhang
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
| | - Taotao Wang
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
| | - Zhibiao Ye
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
| | - Changxian Yang
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
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11
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Ali MF, Fatema U, Peng X, Hacker SW, Maruyama D, Sun MX, Kawashima T. ARP2/3-independent WAVE/SCAR pathway and class XI myosin control sperm nuclear migration in flowering plants. Proc Natl Acad Sci U S A 2020; 117:32757-32763. [PMID: 33288691 PMCID: PMC7768783 DOI: 10.1073/pnas.2015550117] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
After eukaryotic fertilization, gamete nuclei migrate to fuse parental genomes in order to initiate development of the next generation. In most animals, microtubules control female and male pronuclear migration in the zygote. Flowering plants, on the other hand, have evolved actin filament (F-actin)-based sperm nuclear migration systems for karyogamy. Flowering plants have also evolved a unique double-fertilization process: two female gametophytic cells, the egg and central cells, are each fertilized by a sperm cell. The molecular and cellular mechanisms of how flowering plants utilize and control F-actin for double-fertilization events are largely unknown. Using confocal microscopy live-cell imaging with a combination of pharmacological and genetic approaches, we identified factors involved in F-actin dynamics and sperm nuclear migration in Arabidopsis thaliana (Arabidopsis) and Nicotiana tabacum (tobacco). We demonstrate that the F-actin regulator, SCAR2, but not the ARP2/3 protein complex, controls the coordinated active F-actin movement. These results imply that an ARP2/3-independent WAVE/SCAR-signaling pathway regulates F-actin dynamics in female gametophytic cells for fertilization. We also identify that the class XI myosin XI-G controls active F-actin movement in the Arabidopsis central cell. XI-G is not a simple transporter, moving cargos along F-actin, but can generate forces that control the dynamic movement of F-actin for fertilization. Our results provide insights into the mechanisms that control gamete nuclear migration and reveal regulatory pathways for dynamic F-actin movement in flowering plants.
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Affiliation(s)
- Mohammad Foteh Ali
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY 40546-0312
| | - Umma Fatema
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY 40546-0312
| | - Xiongbo Peng
- State Key Laboratory of Hybrid Rice, College of Life Science, Wuhan University, 430072 Wuhan, China
| | - Samuel W Hacker
- Agriculture and Medical Biotechnology Program, University of Kentucky, Lexington, KY 40546-0312
| | - Daisuke Maruyama
- Kihara Institute for Biological Research, Yokohama City University, 244-0813 Yokohama, Kanagawa, Japan
| | - Meng-Xiang Sun
- State Key Laboratory of Hybrid Rice, College of Life Science, Wuhan University, 430072 Wuhan, China
| | - Tomokazu Kawashima
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY 40546-0312;
- Agriculture and Medical Biotechnology Program, University of Kentucky, Lexington, KY 40546-0312
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12
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Liu HK, Li YJ, Wang SJ, Yuan TL, Huang WJ, Dong X, Pei JQ, Zhang D, McCormick S, Tang WH. Kinase Partner Protein Plays a Key Role in Controlling the Speed and Shape of Pollen Tube Growth in Tomato. PLANT PHYSIOLOGY 2020; 184:1853-1869. [PMID: 33020251 PMCID: PMC7723124 DOI: 10.1104/pp.20.01081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 09/23/2020] [Indexed: 05/10/2023]
Abstract
The rapid and responsive growth of a pollen tube requires delicate coordination of membrane receptor signaling, Rho-of-Plants (ROP) GTPase activity switching, and actin cytoskeleton assembly. The tomato (Solanum lycopersicum) kinase partner protein (KPP), is a ROP guanine nucleotide exchange factor (GEF) that activates ROP GTPases and interacts with the tomato pollen receptor kinases LePRK1 and LePRK2. It remains unclear how KPP relays signals from plasma membrane-localized LePRKs to ROP switches and other cellular machineries to modulate pollen tube growth. Here, we biochemically verified KPP's activity on ROP4 and showed that KPP RNA interference transgenic pollen tubes grew slower while KPP-overexpressing pollen tubes grew faster, suggesting that KPP functions as a rheostat for speed control in LePRK2-mediated pollen tube growth. The N terminus of KPP is required for self-inhibition of its ROPGEF activity, and expression of truncated KPP lacking the N terminus caused pollen tube tip enlargement. The C-terminus of KPP is required for its interaction with LePRK1 and LePRK2, and the expression of a truncated KPP lacking the C-terminus triggered pollen tube bifurcation. Furthermore, coexpression assays showed that self-associated KPP recruited actin-nucleating Actin-Related Protein2/3 (ARP2/3) complexes to the tip membrane. Interfering with ARP2/3 activity reduced the pollen tube abnormalities caused by overexpressing KPP fragments. In conclusion, KPP plays a key role in pollen tube speed and shape control by recruiting the branched actin nucleator ARP2/3 complex and an actin bundler to the membrane-localized receptors LePRK1 and LePRK2.
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Affiliation(s)
- Hai-Kuan Liu
- National Key Laboratory of Plant Molecular Genetics, Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yu-Jie Li
- National Key Laboratory of Plant Molecular Genetics, Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shu-Jie Wang
- National Key Laboratory of Plant Molecular Genetics, Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ting-Lu Yuan
- National Key Laboratory of Plant Molecular Genetics, Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wei-Jie Huang
- National Key Laboratory of Plant Molecular Genetics, Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xin Dong
- National Key Laboratory of Plant Molecular Genetics, Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jia-Qi Pei
- National Key Laboratory of Plant Molecular Genetics, Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Dong Zhang
- National Key Laboratory of Plant Molecular Genetics, Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Sheila McCormick
- Plant Gene Expression Center, United States Department of Agriculture/Agricultural Research Service, and Department of Plant and Microbial Biology, University of California at Berkeley, Albany, California 94710
| | - Wei-Hua Tang
- National Key Laboratory of Plant Molecular Genetics, Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
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13
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Gavrin A, Rey T, Torode TA, Toulotte J, Chatterjee A, Kaplan JL, Evangelisti E, Takagi H, Charoensawan V, Rengel D, Journet EP, Debellé F, de Carvalho-Niebel F, Terauchi R, Braybrook S, Schornack S. Developmental Modulation of Root Cell Wall Architecture Confers Resistance to an Oomycete Pathogen. Curr Biol 2020; 30:4165-4176.e5. [PMID: 32888486 PMCID: PMC7658807 DOI: 10.1016/j.cub.2020.08.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 07/08/2020] [Accepted: 08/04/2020] [Indexed: 11/26/2022]
Abstract
The cell wall is the primary interface between plant cells and their immediate environment and must balance multiple functionalities, including the regulation of growth, the entry of beneficial microbes, and protection against pathogens. Here, we demonstrate how API, a SCAR2 protein component of the SCAR/WAVE complex, controls the root cell wall architecture important for pathogenic oomycete and symbiotic bacterial interactions in legumes. A mutation in API results in root resistance to the pathogen Phytophthora palmivora and colonization defects by symbiotic rhizobia. Although api mutant plants do not exhibit significant overall growth and development defects, their root cells display delayed actin and endomembrane trafficking dynamics and selectively secrete less of the cell wall polysaccharide xyloglucan. Changes associated with a loss of API establish a cell wall architecture with altered biochemical properties that hinder P. palmivora infection progress. Thus, developmental stage-dependent modifications of the cell wall, driven by SCAR/WAVE, are important in balancing cell wall developmental functions and microbial invasion. The SCAR protein API controls actin and endomembrane trafficking dynamics SCAR proteins of several plant species can support symbiosis and pathogen infection A mutation in API affects specific biochemical properties of plant cell walls An altered wall architecture results in root resistance to Phytophthora palmivora
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Affiliation(s)
- Aleksandr Gavrin
- Sainsbury Laboratory (SLCU), University of Cambridge, 47 Bateman Street, Cambridge CB2 1LR, UK
| | - Thomas Rey
- Sainsbury Laboratory (SLCU), University of Cambridge, 47 Bateman Street, Cambridge CB2 1LR, UK
| | - Thomas A Torode
- Sainsbury Laboratory (SLCU), University of Cambridge, 47 Bateman Street, Cambridge CB2 1LR, UK
| | - Justine Toulotte
- Sainsbury Laboratory (SLCU), University of Cambridge, 47 Bateman Street, Cambridge CB2 1LR, UK
| | - Abhishek Chatterjee
- Sainsbury Laboratory (SLCU), University of Cambridge, 47 Bateman Street, Cambridge CB2 1LR, UK
| | - Jonathan Louis Kaplan
- Sainsbury Laboratory (SLCU), University of Cambridge, 47 Bateman Street, Cambridge CB2 1LR, UK
| | - Edouard Evangelisti
- Sainsbury Laboratory (SLCU), University of Cambridge, 47 Bateman Street, Cambridge CB2 1LR, UK
| | - Hiroki Takagi
- Iwate Biotechnology Institute, 22-174-4 Narita, Kitakami, Iwate 024-0003, Japan
| | - Varodom Charoensawan
- Sainsbury Laboratory (SLCU), University of Cambridge, 47 Bateman Street, Cambridge CB2 1LR, UK; Department of Biochemistry, Faculty of Science, and Integrative Computational BioScience (ICBS) Center, Mahidol University, Bangkok 10400, Thailand
| | - David Rengel
- LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan 31326, France; GeT-PlaGe, Genotoul, INRA US1426, Castanet-Tolosan Cedex, France
| | - Etienne-Pascal Journet
- LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan 31326, France; AGIR, Université de Toulouse, INRA, ENSFEA, Castanet-Tolosan 31326, France
| | - Frédéric Debellé
- LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan 31326, France
| | | | - Ryohei Terauchi
- Iwate Biotechnology Institute, 22-174-4 Narita, Kitakami, Iwate 024-0003, Japan
| | - Siobhan Braybrook
- Sainsbury Laboratory (SLCU), University of Cambridge, 47 Bateman Street, Cambridge CB2 1LR, UK; Department of Molecular, Cell, and Developmental Biology, 610 Charles E Young Drive South, University of California, Los Angeles, Los Angeles, CA 90095, USA; Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA; Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Sebastian Schornack
- Sainsbury Laboratory (SLCU), University of Cambridge, 47 Bateman Street, Cambridge CB2 1LR, UK.
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14
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Cifrová P, Oulehlová D, Kollárová E, Martinek J, Rosero A, Žárský V, Schwarzerová K, Cvrčková F. Division of Labor Between Two Actin Nucleators-the Formin FH1 and the ARP2/3 Complex-in Arabidopsis Epidermal Cell Morphogenesis. FRONTIERS IN PLANT SCIENCE 2020; 11:148. [PMID: 32194585 PMCID: PMC7061858 DOI: 10.3389/fpls.2020.00148] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Accepted: 01/30/2020] [Indexed: 05/11/2023]
Abstract
The ARP2/3 complex and formins are the only known plant actin nucleators. Besides their actin-related functions, both systems also modulate microtubule organization and dynamics. Loss of the main housekeeping Arabidopsis thaliana Class I membrane-targeted formin FH1 (At3g25500) is known to increase cotyledon pavement cell lobing, while mutations affecting ARP2/3 subunits exhibit an opposite effect. Here we examine the role of FH1 and the ARP2/3 complex subunit ARPC5 (At4g01710) in epidermal cell morphogenesis with focus on pavement cells and trichomes using a model system of single fh1 and arpc5, as well as double fh1 arpc5 mutants. While cotyledon pavement cell shape in double mutants mostly resembled single arpc5 mutants, analysis of true leaf epidermal morphology, as well as actin and microtubule organization and dynamics, revealed a more complex relationship between the two systems and similar, rather than antagonistic, effects on some parameters. Both fh1 and arpc5 mutations increased actin network density and increased cell shape complexity in pavement cells and trichomes of first true leaves, in contrast to cotyledons. Thus, while the two actin nucleation systems have complementary roles in some aspects of cell morphogenesis in cotyledon pavement cells, they may act in parallel in other cell types and developmental stages.
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Affiliation(s)
- Petra Cifrová
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
| | - Denisa Oulehlová
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
- Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Prague, Czechia
| | - Eva Kollárová
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
| | - Jan Martinek
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
| | - Amparo Rosero
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
| | - Viktor Žárský
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
- Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Prague, Czechia
| | - Kateřina Schwarzerová
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
| | - Fatima Cvrčková
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
- *Correspondence: Fatima Cvrčková,
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15
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Arribas-Hernández L, Brodersen P. Occurrence and Functions of m 6A and Other Covalent Modifications in Plant mRNA. PLANT PHYSIOLOGY 2020; 182:79-96. [PMID: 31748418 PMCID: PMC6945878 DOI: 10.1104/pp.19.01156] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 11/13/2019] [Indexed: 05/07/2023]
Abstract
Posttranscriptional control of gene expression is indispensable for the execution of developmental programs and environmental adaptation. Among the many cellular mechanisms that regulate mRNA fate, covalent nucleotide modification has emerged as a major way of controlling the processing, localization, stability, and translatability of mRNAs. This powerful mechanism is conserved across eukaryotes and controls the cellular events that lead to development and growth. As in other eukaryotes, N 6-methylation of adenosine is the most abundant and best studied mRNA modification in flowering plants. It is essential for embryonic and postembryonic plant development and it affects growth rate and stress responses, including susceptibility to plant RNA viruses. Although the mRNA modification field is young, the intense interest triggered by its involvement in stem cell differentiation and cancer has led to rapid advances in understanding how mRNA modifications control gene expression in mammalian systems. An equivalent effort from plant molecular biologists has been lagging behind, but recent work in Arabidopsis (Arabidopsis thaliana) and other plant species is starting to give insights into how this essential layer of posttranscriptional regulation works in plants, and both similarities and differences with other eukaryotes are emerging. In this Update, we summarize, connect, and evaluate the experimental work that supports our current knowledge of the biochemistry, molecular mechanisms, and biological functions of mRNA modifications in plants. We devote particular attention to N 6-methylation of adenosine and attempt to place the knowledge gained from plant studies within the context of a more general framework derived from studies in other eukaryotes.
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Affiliation(s)
| | - Peter Brodersen
- University of Copenhagen, Department of Biology, DK-2200 Copenhagen N, Denmark
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16
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Pratap Sahi V, Cifrová P, García-González J, Kotannal Baby I, Mouillé G, Gineau E, Müller K, Baluška F, Soukup A, Petrášek J, Schwarzerová K. Arabidopsis thaliana plants lacking the ARP2/3 complex show defects in cell wall assembly and auxin distribution. ANNALS OF BOTANY 2018; 122:777-789. [PMID: 29293873 PMCID: PMC6215044 DOI: 10.1093/aob/mcx178] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 11/10/2017] [Indexed: 05/25/2023]
Abstract
BACKGROUND AND AIM The cytoskeleton plays an important role in the synthesis of plant cell walls. Both microtubules and actin cytoskeleton are known to be involved in the morphogenesis of plant cells through their role in cell wall building. The role of ARP2/3-nucleated actin cytoskeleton in the morphogenesis of cotyledon pavement cells has been described before. Seedlings of Arabidopsis mutants lacking a functional ARP2/3 complex display specific cell wall-associated defects. METHODS In three independent Arabidopsis mutant lines lacking subunits of the ARP2/3 complex, phenotypes associated with the loss of the complex were analysed throughout plant development. Organ size and anatomy, cell wall composition, and auxin distribution were investigated. KEY RESULTS ARP2/3-related phenotype is associated with changes in cell wall composition, and the phenotype is manifested especially in mature tissues. Cell walls of mature plants contain less cellulose and a higher amount of homogalacturonan, and display changes in cell wall lignification. Vascular bundles of mutant inflorescence stems show a changed pattern of AUX1-YFP expression. Plants lacking a functional ARP2/3 complex have decreased basipetal auxin transport. CONCLUSIONS The results suggest that the ARP2/3 complex has a morphogenetic function related to cell wall synthesis and auxin transport.
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Affiliation(s)
- Vaidurya Pratap Sahi
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná, Czech Republic
| | - Petra Cifrová
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná, Czech Republic
| | - Judith García-González
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná, Czech Republic
| | | | - Gregory Mouillé
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, Versailles, France
| | - Emilie Gineau
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, Versailles, France
| | - Karel Müller
- Institute of Experimental Botany, AS CR, Rozvojová, Czech Republic
| | - František Baluška
- Department of Plant Cell Biology, Institute of Cellular and Molecular Botany, University of Bonn, Kirschallee, Bonn, Germany
| | - Aleš Soukup
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná, Czech Republic
| | - Jan Petrášek
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná, Czech Republic
- Institute of Experimental Botany, AS CR, Rozvojová, Czech Republic
| | - Kateřina Schwarzerová
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná, Czech Republic
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17
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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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18
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Ren H, Dang X, Cai X, Yu P, Li Y, Zhang S, Liu M, Chen B, Lin D. Spatio-temporal orientation of microtubules controls conical cell shape in Arabidopsis thaliana petals. PLoS Genet 2017. [PMID: 28644898 PMCID: PMC5507347 DOI: 10.1371/journal.pgen.1006851] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The physiological functions of epidermal cells are largely determined by their diverse morphologies. Most flowering plants have special conical-shaped petal epidermal cells that are thought to influence light capture and reflectance, and provide pollinator grips, but the molecular mechanisms controlling conical cell shape remain largely unknown. Here, we developed a live-confocal imaging approach to quantify geometric parameters of conical cells in Arabidopsis thaliana (A. thaliana). Through genetic screens, we identified katanin (KTN1) mutants showing a phenotype of decreased tip sharpening of conical cells. Furthermore, we demonstrated that SPIKE1 and Rho of Plants (ROP) GTPases were required for the final shape formation of conical cells, as KTN1 does. Live-cell imaging showed that wild-type cells exhibited random orientation of cortical microtubule arrays at early developmental stages but displayed a well-ordered circumferential orientation of microtubule arrays at later stages. By contrast, loss of KTN1 prevented random microtubule networks from shifting into well-ordered arrays. We further showed that the filamentous actin cap, which is a typical feature of several plant epidermal cell types including root hairs and leaf trichomes, was not observed in the growth apexes of conical cells during cell development. Moreover, our genetic and pharmacological data suggested that microtubules but not actin are required for conical cell shaping. Together, our results provide a novel imaging approach for studying petal conical cell morphogenesis and suggest that the spatio-temporal organization of microtubule arrays plays crucial roles in controlling conical cell shape. How cells achieve their final shapes is a fundamental question in biology. Most flowering plants have special conical-shaped petal epidermal cells that are thought to attract pollinators, but the molecular and genetic mechanisms that control conical cell shape remain unknown. In this study, we developed a live-confocal imaging approach for the quantitative study of conical cell morphogenesis. Through genetic screens, we showed that A. thaliana KTN1, ROP GTPases, and SPIKE1 are required for conical cell shaping. Live-cell imaging showed that loss of KTN1 prevented random microtubule networks from shifting into well-ordered microtubule arrays at later developmental stages, which is correlated with the tip sharpening of conical cells. Moreover, genetic and pharmacological data suggested that microtubules but not actin are required for conical cell shaping. Together, our findings provide significant insights into the spatio-temporal organization of microtubules that controls conical cell development.
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Affiliation(s)
- Huibo Ren
- Basic Forestry and Proteomics Research Center, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, China.,Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Xie Dang
- Basic Forestry and Proteomics Research Center, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Xianzhi Cai
- Basic Forestry and Proteomics Research Center, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Peihang Yu
- Basic Forestry and Proteomics Research Center, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Yajun Li
- Basic Forestry and Proteomics Research Center, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Shanshan Zhang
- Basic Forestry and Proteomics Research Center, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Menghong Liu
- Basic Forestry and Proteomics Research Center, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Binqing Chen
- Basic Forestry and Proteomics Research Center, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, China.,Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Deshu Lin
- Basic Forestry and Proteomics Research Center, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, China.,Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, China
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19
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Wang P, Richardson C, Hawes C, Hussey P. Arabidopsis NAP1 Regulates the Formation of Autophagosomes. Curr Biol 2016; 26:2060-2069. [DOI: 10.1016/j.cub.2016.06.008] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 05/25/2016] [Accepted: 06/06/2016] [Indexed: 01/10/2023]
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20
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Zhou W, Wang Y, Wu Z, Luo L, Liu P, Yan L, Hou S. Homologs of SCAR/WAVE complex components are required for epidermal cell morphogenesis in rice. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:4311-23. [PMID: 27252469 PMCID: PMC5301933 DOI: 10.1093/jxb/erw214] [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: 05/18/2023]
Abstract
Filamentous actins (F-actins) play a vital role in epidermal cell morphogenesis. However, a limited number of studies have examined actin-dependent leaf epidermal cell morphogenesis events in rice. In this study, two recessive mutants were isolated: less pronounced lobe epidermal cell2-1 (lpl2-1) and lpl3-1, whose leaf and stem epidermis developed a smooth surface, with fewer serrated pavement cell (PC) lobes, and decreased papillae. The lpl2-1 also exhibited irregular stomata patterns, reduced plant height, and short panicles and roots. Molecular genetic studies demonstrated that LPL2 and LPL3 encode the PIROGI/Specifically Rac1-associated protein 1 (PIR/SRA1)-like and NCK-associated protein 1 (NAP1)-like proteins, respectively, two components of the suppressor of cAMP receptor/Wiskott-Aldrich syndrome protein-family verprolin-homologous protein (SCAR/WAVE) regulatory complex involved in actin nucleation and function. Epidermal cells exhibited abnormal arrangement of F-actins in both lpl2 and lpl3 expanding leaves. Moreover, the distorted trichomes of Arabidopsis pir could be partially restored by an overexpression of LPL2 A yeast two-hybrid assay revealed that LPL2 can directly interact with LPL3 in vitro Collectively, the results indicate that LPL2 and LPL3 are two functionally conserved homologs of the SCAR/WAVE complex components, and that they play an important role in controlling epidermal cell morphogenesis in rice by organising F-actin.
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Affiliation(s)
- Wenqi Zhou
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Yuchuan Wang
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Zhongliang Wu
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Liang Luo
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Ping Liu
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Longfeng Yan
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Suiwen Hou
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
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Havelková L, Nanda G, Martinek J, Bellinvia E, Sikorová L, Šlajcherová K, Seifertová D, Fischer L, Fišerová J, Petrášek J, Schwarzerová K. Arp2/3 complex subunit ARPC2 binds to microtubules. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2015; 241:96-108. [PMID: 26706062 DOI: 10.1016/j.plantsci.2015.10.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Revised: 09/30/2015] [Accepted: 10/01/2015] [Indexed: 05/03/2023]
Abstract
Arp2/3 complex plays a fundamental role in the nucleation of actin filaments (AFs) in yeasts, plants, and animals. In plants, the aberrant shaping and elongation of several types of epidermal cells observed in Arp2/3 complex knockout plant mutants suggest the importance of Arp2/3-mediated actin nucleation for various morphogenetic processes. Here we show that ARPC2, a core Arp2/3 complex subunit, interacts with both actin filaments (AFs) and microtubules (MTs). Plant GFP-ARPC2 expressed in Nicotiana tabacum BY-2 cells, leaf epidermal cells of Nicotiana benthamiana and root epidermal cells of Arabidopsis thaliana decorated MTs. The interaction with MTs was demonstrated by pharmacological approach selectively interfering with either AFs or MTs dynamics as well as by the in vitro co-sedimentation assays. A putative MT-binding domain of tobacco NtARPC2 protein was identified using the co-sedimentation of several truncated NtARPC2 proteins with MTs. Newly identified MT-binding ability of ARPC2 subunit of Arp2/3 complex may represent a new molecular mechanism of AFs and MTs interaction.
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Affiliation(s)
- Lenka Havelková
- Charles University in Prague, Faculty of Science, Department of Experimental Plant Biology, Viničná 5, 128 44 Prague 2, Czech Republic
| | - Gitanjali Nanda
- Charles University in Prague, Faculty of Science, Department of Experimental Plant Biology, Viničná 5, 128 44 Prague 2, Czech Republic
| | - Jan Martinek
- Charles University in Prague, Faculty of Science, Department of Experimental Plant Biology, Viničná 5, 128 44 Prague 2, Czech Republic
| | - Erica Bellinvia
- Charles University in Prague, Faculty of Science, Department of Experimental Plant Biology, Viničná 5, 128 44 Prague 2, Czech Republic
| | - Lenka Sikorová
- Charles University in Prague, Faculty of Science, Department of Experimental Plant Biology, Viničná 5, 128 44 Prague 2, Czech Republic
| | - Kateřina Šlajcherová
- Charles University in Prague, Faculty of Science, Department of Experimental Plant Biology, Viničná 5, 128 44 Prague 2, Czech Republic
| | - Daniela Seifertová
- Charles University in Prague, Faculty of Science, Department of Experimental Plant Biology, Viničná 5, 128 44 Prague 2, Czech Republic
| | - Lukáš Fischer
- Charles University in Prague, Faculty of Science, Department of Experimental Plant Biology, Viničná 5, 128 44 Prague 2, Czech Republic
| | - Jindřiška Fišerová
- Charles University in Prague, Faculty of Science, Department of Experimental Plant Biology, Viničná 5, 128 44 Prague 2, Czech Republic
| | - Jan Petrášek
- Charles University in Prague, Faculty of Science, Department of Experimental Plant Biology, Viničná 5, 128 44 Prague 2, Czech Republic
| | - Kateřina Schwarzerová
- Charles University in Prague, Faculty of Science, Department of Experimental Plant Biology, Viničná 5, 128 44 Prague 2, Czech Republic.
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Qiu L, Lin JS, Xu J, Sato S, Parniske M, Wang TL, Downie JA, Xie F. SCARN a Novel Class of SCAR Protein That Is Required for Root-Hair Infection during Legume Nodulation. PLoS Genet 2015; 11:e1005623. [PMID: 26517270 PMCID: PMC4627827 DOI: 10.1371/journal.pgen.1005623] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2015] [Accepted: 09/30/2015] [Indexed: 12/22/2022] Open
Abstract
Rhizobial infection of legume root hairs requires a rearrangement of the actin cytoskeleton to enable the establishment of plant-made infection structures called infection threads. In the SCAR/WAVE (Suppressor of cAMP receptor defect/WASP family verpolin homologous protein) actin regulatory complex, the conserved N-terminal domains of SCAR proteins interact with other components of the SCAR/WAVE complex. The conserved C-terminal domains of SCAR proteins bind to and activate the actin-related protein 2/3 (ARP2/3) complex, which can bind to actin filaments catalyzing new actin filament formation by nucleating actin branching. We have identified, SCARN (SCAR-Nodulation), a gene required for root hair infection of Lotus japonicus by Mesorhizobium loti. Although the SCARN protein is related to Arabidopsis thaliana SCAR2 and SCAR4, it belongs to a distinct legume-sub clade. We identified other SCARN-like proteins in legumes and phylogeny analyses suggested that SCARN may have arisen from a gene duplication and acquired specialized functions in root nodule symbiosis. Mutation of SCARN reduced formation of infection-threads and their extension into the root cortex and slightly reduced root-hair length. Surprisingly two of the scarn mutants showed constitutive branching of root hairs in uninoculated plants. However we observed no effect of scarn mutations on trichome development or on the early actin cytoskeletal accumulation that is normally seen in root hair tips shortly after M. loti inoculation, distinguishing them from other symbiosis mutations affecting actin nucleation. The C-terminal domain of SCARN binds to ARPC3 and ectopic expression of the N-terminal SCAR-homology domain (but not the full length protein) inhibited nodulation. In addition, we found that SCARN expression is enhanced by M. loti in epidermal cells and that this is directly regulated by the NODULE INCEPTION (NIN) transcription factor. Characterization of Lotus japonicus mutants defective for nodule infection by rhizobia led to the identification of a gene we named SCARN. Two of the five alleles caused formation of branched root-hairs in uninoculated seedlings, suggesting SCARN plays a role in the microtubule and actin-regulated polar growth of root hairs. SCARN is one of three L. japonicus proteins containing the conserved N and C terminal domains predicted to be required for rearrangement of the actin cytoskeleton. SCARN expression is induced in response to rhizobial nodulation factors by the NIN (NODULE INCEPTION) transcription factor and appears to be adapted to promoting rhizobial infection, possibly arising from a gene duplication event. SCARN binds to ARPC3, one of the predicted components in the actin-related protein complex involved in the activation of actin nucleation.
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Affiliation(s)
- Liping Qiu
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Jie-shun Lin
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Ji Xu
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Shusei Sato
- Kazusa DNA Research Institute, Kisarazu, Japan
- Graduate School of Life Sciences, Tohoku University, Sendai, Japan
| | - Martin Parniske
- University of Munich LMU, Faculty of Biology, Martinsried, Germany
| | | | | | - Fang Xie
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
- * E-mail:
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23
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Rao Y, Yang Y, Xu J, Li X, Leng Y, Dai L, Huang L, Shao G, Ren D, Hu J, Guo L, Pan J, Zeng D. EARLY SENESCENCE1 Encodes a SCAR-LIKE PROTEIN2 That Affects Water Loss in Rice. PLANT PHYSIOLOGY 2015; 169:1225-39. [PMID: 26243619 PMCID: PMC4587469 DOI: 10.1104/pp.15.00991] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 08/01/2015] [Indexed: 05/21/2023]
Abstract
The global problem of drought threatens agricultural production and constrains the development of sustainable agricultural practices. In plants, excessive water loss causes drought stress and induces early senescence. In this study, we isolated a rice (Oryza sativa) mutant, designated as early senescence1 (es1), which exhibits early leaf senescence. The es1-1 leaves undergo water loss at the seedling stage (as reflected by whitening of the leaf margin and wilting) and display early senescence at the three-leaf stage. We used map-based cloning to identify ES1, which encodes a SCAR-LIKE PROTEIN2, a component of the suppressor of cAMP receptor/Wiskott-Aldrich syndrome protein family verprolin-homologous complex involved in actin polymerization and function. The es1-1 mutants exhibited significantly higher stomatal density. This resulted in excessive water loss and accelerated water flow in es1-1, also enhancing the water absorption capacity of the roots and the water transport capacity of the stems as well as promoting the in vivo enrichment of metal ions cotransported with water. The expression of ES1 is higher in the leaves and leaf sheaths than in other tissues, consistent with its role in controlling water loss from leaves. GREEN FLUORESCENT PROTEIN-ES1 fusion proteins were ubiquitously distributed in the cytoplasm of plant cells. Collectively, our data suggest that ES1 is important for regulating water loss in rice.
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Affiliation(s)
- Yuchun Rao
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, China (Y.R., Y.Y., J.X., Y.L., L.D., L.H., G.S., D.R., J.H., L.G., D.Z.);College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, China (Y.R., X.L., J.P.); andKey Laboratory of Crop Physiology, Ecology, and Genetic Breeding, Ministry of Education, Jiangxi Agricultural University, Nanchang 330045, China (Y.Y., J.X.)
| | - Yaolong Yang
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, China (Y.R., Y.Y., J.X., Y.L., L.D., L.H., G.S., D.R., J.H., L.G., D.Z.);College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, China (Y.R., X.L., J.P.); andKey Laboratory of Crop Physiology, Ecology, and Genetic Breeding, Ministry of Education, Jiangxi Agricultural University, Nanchang 330045, China (Y.Y., J.X.)
| | - Jie Xu
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, China (Y.R., Y.Y., J.X., Y.L., L.D., L.H., G.S., D.R., J.H., L.G., D.Z.);College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, China (Y.R., X.L., J.P.); andKey Laboratory of Crop Physiology, Ecology, and Genetic Breeding, Ministry of Education, Jiangxi Agricultural University, Nanchang 330045, China (Y.Y., J.X.)
| | - Xiaojing Li
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, China (Y.R., Y.Y., J.X., Y.L., L.D., L.H., G.S., D.R., J.H., L.G., D.Z.);College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, China (Y.R., X.L., J.P.); andKey Laboratory of Crop Physiology, Ecology, and Genetic Breeding, Ministry of Education, Jiangxi Agricultural University, Nanchang 330045, China (Y.Y., J.X.)
| | - Yujia Leng
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, China (Y.R., Y.Y., J.X., Y.L., L.D., L.H., G.S., D.R., J.H., L.G., D.Z.);College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, China (Y.R., X.L., J.P.); andKey Laboratory of Crop Physiology, Ecology, and Genetic Breeding, Ministry of Education, Jiangxi Agricultural University, Nanchang 330045, China (Y.Y., J.X.)
| | - Liping Dai
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, China (Y.R., Y.Y., J.X., Y.L., L.D., L.H., G.S., D.R., J.H., L.G., D.Z.);College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, China (Y.R., X.L., J.P.); andKey Laboratory of Crop Physiology, Ecology, and Genetic Breeding, Ministry of Education, Jiangxi Agricultural University, Nanchang 330045, China (Y.Y., J.X.)
| | - Lichao Huang
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, China (Y.R., Y.Y., J.X., Y.L., L.D., L.H., G.S., D.R., J.H., L.G., D.Z.);College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, China (Y.R., X.L., J.P.); andKey Laboratory of Crop Physiology, Ecology, and Genetic Breeding, Ministry of Education, Jiangxi Agricultural University, Nanchang 330045, China (Y.Y., J.X.)
| | - Guosheng Shao
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, China (Y.R., Y.Y., J.X., Y.L., L.D., L.H., G.S., D.R., J.H., L.G., D.Z.);College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, China (Y.R., X.L., J.P.); andKey Laboratory of Crop Physiology, Ecology, and Genetic Breeding, Ministry of Education, Jiangxi Agricultural University, Nanchang 330045, China (Y.Y., J.X.)
| | - Deyong Ren
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, China (Y.R., Y.Y., J.X., Y.L., L.D., L.H., G.S., D.R., J.H., L.G., D.Z.);College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, China (Y.R., X.L., J.P.); andKey Laboratory of Crop Physiology, Ecology, and Genetic Breeding, Ministry of Education, Jiangxi Agricultural University, Nanchang 330045, China (Y.Y., J.X.)
| | - Jiang Hu
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, China (Y.R., Y.Y., J.X., Y.L., L.D., L.H., G.S., D.R., J.H., L.G., D.Z.);College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, China (Y.R., X.L., J.P.); andKey Laboratory of Crop Physiology, Ecology, and Genetic Breeding, Ministry of Education, Jiangxi Agricultural University, Nanchang 330045, China (Y.Y., J.X.)
| | - Longbiao Guo
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, China (Y.R., Y.Y., J.X., Y.L., L.D., L.H., G.S., D.R., J.H., L.G., D.Z.);College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, China (Y.R., X.L., J.P.); andKey Laboratory of Crop Physiology, Ecology, and Genetic Breeding, Ministry of Education, Jiangxi Agricultural University, Nanchang 330045, China (Y.Y., J.X.)
| | - Jianwei Pan
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, China (Y.R., Y.Y., J.X., Y.L., L.D., L.H., G.S., D.R., J.H., L.G., D.Z.);College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, China (Y.R., X.L., J.P.); andKey Laboratory of Crop Physiology, Ecology, and Genetic Breeding, Ministry of Education, Jiangxi Agricultural University, Nanchang 330045, China (Y.Y., J.X.)
| | - Dali Zeng
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, China (Y.R., Y.Y., J.X., Y.L., L.D., L.H., G.S., D.R., J.H., L.G., D.Z.);College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, China (Y.R., X.L., J.P.); andKey Laboratory of Crop Physiology, Ecology, and Genetic Breeding, Ministry of Education, Jiangxi Agricultural University, Nanchang 330045, China (Y.Y., J.X.)
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24
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Bai J, Zhu X, Wang Q, Zhang J, Chen H, Dong G, Zhu L, Zheng H, Xie Q, Nian J, Chen F, Fu Y, Qian Q, Zuo J. Rice TUTOU1 Encodes a Suppressor of cAMP Receptor-Like Protein That Is Important for Actin Organization and Panicle Development. PLANT PHYSIOLOGY 2015; 169:1179-91. [PMID: 26243616 PMCID: PMC4587440 DOI: 10.1104/pp.15.00229] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Accepted: 07/27/2015] [Indexed: 05/12/2023]
Abstract
Panicle development, a key event in rice (Oryza sativa) reproduction and a critical determinant of grain yield, forms a branched structure containing multiple spikelets. Genetic and environmental factors can perturb panicle development, causing panicles to degenerate and producing characteristic whitish, small spikelets with severely reduced fertility and yield; however, little is known about the molecular basis of the formation of degenerating panicles in rice. Here, we report the identification and characterization of the rice panicle degenerative mutant tutou1 (tut1), which shows severe defects in panicle development. The tut1 also shows a pleiotropic phenotype, characterized by short roots, reduced plant height, and abnormal development of anthers and pollen grains. Molecular genetic studies revealed that TUT1 encodes a suppressor of cAMP receptor/Wiskott-Aldrich syndrome protein family verprolin-homologous (SCAR/WAVE)-like protein. We found that TUT1 contains conserved functional domains found in eukaryotic SCAR/WAVE proteins, and was able to activate Actin-related protein2/3 to promote actin nucleation and polymerization in vitro. Consistently, tut1 mutants show defects in the arrangement of actin filaments in trichome. These results indicate that TUT1 is a functional SCAR/WAVE protein and plays an important role in panicle development.
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Affiliation(s)
- Jiaoteng Bai
- State Key Laboratory of Plant Genomics and National Plant Gene Research Center (J.B., Q.W., J.Zh., H.Z., Q.X., J.N., J.Zu.) and State Key Laboratory of Molecular Developmental Biology and National Plant Gene Research Center (F.C.), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China;University of Chinese Academy of Sciences, Beijing 100049, China (J.B., Q.W., H.Z., Q.X.);State Key Laboratory of Rice Biology, China National Rice Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310006, China (X.Z., H.C., G.D., Q.Q.); andState Key Laboratory of Plant Physiology and Biochemistry, Department of Plant Sciences, College of Biological Sciences, China Agricultural University, Beijing 100193, China (L.Z., Y.F.)
| | - Xudong Zhu
- State Key Laboratory of Plant Genomics and National Plant Gene Research Center (J.B., Q.W., J.Zh., H.Z., Q.X., J.N., J.Zu.) and State Key Laboratory of Molecular Developmental Biology and National Plant Gene Research Center (F.C.), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China;University of Chinese Academy of Sciences, Beijing 100049, China (J.B., Q.W., H.Z., Q.X.);State Key Laboratory of Rice Biology, China National Rice Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310006, China (X.Z., H.C., G.D., Q.Q.); andState Key Laboratory of Plant Physiology and Biochemistry, Department of Plant Sciences, College of Biological Sciences, China Agricultural University, Beijing 100193, China (L.Z., Y.F.)
| | - Qing Wang
- State Key Laboratory of Plant Genomics and National Plant Gene Research Center (J.B., Q.W., J.Zh., H.Z., Q.X., J.N., J.Zu.) and State Key Laboratory of Molecular Developmental Biology and National Plant Gene Research Center (F.C.), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China;University of Chinese Academy of Sciences, Beijing 100049, China (J.B., Q.W., H.Z., Q.X.);State Key Laboratory of Rice Biology, China National Rice Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310006, China (X.Z., H.C., G.D., Q.Q.); andState Key Laboratory of Plant Physiology and Biochemistry, Department of Plant Sciences, College of Biological Sciences, China Agricultural University, Beijing 100193, China (L.Z., Y.F.)
| | - Jian Zhang
- State Key Laboratory of Plant Genomics and National Plant Gene Research Center (J.B., Q.W., J.Zh., H.Z., Q.X., J.N., J.Zu.) and State Key Laboratory of Molecular Developmental Biology and National Plant Gene Research Center (F.C.), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China;University of Chinese Academy of Sciences, Beijing 100049, China (J.B., Q.W., H.Z., Q.X.);State Key Laboratory of Rice Biology, China National Rice Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310006, China (X.Z., H.C., G.D., Q.Q.); andState Key Laboratory of Plant Physiology and Biochemistry, Department of Plant Sciences, College of Biological Sciences, China Agricultural University, Beijing 100193, China (L.Z., Y.F.)
| | - Hongqi Chen
- State Key Laboratory of Plant Genomics and National Plant Gene Research Center (J.B., Q.W., J.Zh., H.Z., Q.X., J.N., J.Zu.) and State Key Laboratory of Molecular Developmental Biology and National Plant Gene Research Center (F.C.), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China;University of Chinese Academy of Sciences, Beijing 100049, China (J.B., Q.W., H.Z., Q.X.);State Key Laboratory of Rice Biology, China National Rice Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310006, China (X.Z., H.C., G.D., Q.Q.); andState Key Laboratory of Plant Physiology and Biochemistry, Department of Plant Sciences, College of Biological Sciences, China Agricultural University, Beijing 100193, China (L.Z., Y.F.)
| | - Guojun Dong
- State Key Laboratory of Plant Genomics and National Plant Gene Research Center (J.B., Q.W., J.Zh., H.Z., Q.X., J.N., J.Zu.) and State Key Laboratory of Molecular Developmental Biology and National Plant Gene Research Center (F.C.), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China;University of Chinese Academy of Sciences, Beijing 100049, China (J.B., Q.W., H.Z., Q.X.);State Key Laboratory of Rice Biology, China National Rice Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310006, China (X.Z., H.C., G.D., Q.Q.); andState Key Laboratory of Plant Physiology and Biochemistry, Department of Plant Sciences, College of Biological Sciences, China Agricultural University, Beijing 100193, China (L.Z., Y.F.)
| | - Lei Zhu
- State Key Laboratory of Plant Genomics and National Plant Gene Research Center (J.B., Q.W., J.Zh., H.Z., Q.X., J.N., J.Zu.) and State Key Laboratory of Molecular Developmental Biology and National Plant Gene Research Center (F.C.), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China;University of Chinese Academy of Sciences, Beijing 100049, China (J.B., Q.W., H.Z., Q.X.);State Key Laboratory of Rice Biology, China National Rice Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310006, China (X.Z., H.C., G.D., Q.Q.); andState Key Laboratory of Plant Physiology and Biochemistry, Department of Plant Sciences, College of Biological Sciences, China Agricultural University, Beijing 100193, China (L.Z., Y.F.)
| | - Huakun Zheng
- State Key Laboratory of Plant Genomics and National Plant Gene Research Center (J.B., Q.W., J.Zh., H.Z., Q.X., J.N., J.Zu.) and State Key Laboratory of Molecular Developmental Biology and National Plant Gene Research Center (F.C.), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China;University of Chinese Academy of Sciences, Beijing 100049, China (J.B., Q.W., H.Z., Q.X.);State Key Laboratory of Rice Biology, China National Rice Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310006, China (X.Z., H.C., G.D., Q.Q.); andState Key Laboratory of Plant Physiology and Biochemistry, Department of Plant Sciences, College of Biological Sciences, China Agricultural University, Beijing 100193, China (L.Z., Y.F.)
| | - Qingjun Xie
- State Key Laboratory of Plant Genomics and National Plant Gene Research Center (J.B., Q.W., J.Zh., H.Z., Q.X., J.N., J.Zu.) and State Key Laboratory of Molecular Developmental Biology and National Plant Gene Research Center (F.C.), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China;University of Chinese Academy of Sciences, Beijing 100049, China (J.B., Q.W., H.Z., Q.X.);State Key Laboratory of Rice Biology, China National Rice Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310006, China (X.Z., H.C., G.D., Q.Q.); andState Key Laboratory of Plant Physiology and Biochemistry, Department of Plant Sciences, College of Biological Sciences, China Agricultural University, Beijing 100193, China (L.Z., Y.F.)
| | - Jinqiang Nian
- State Key Laboratory of Plant Genomics and National Plant Gene Research Center (J.B., Q.W., J.Zh., H.Z., Q.X., J.N., J.Zu.) and State Key Laboratory of Molecular Developmental Biology and National Plant Gene Research Center (F.C.), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China;University of Chinese Academy of Sciences, Beijing 100049, China (J.B., Q.W., H.Z., Q.X.);State Key Laboratory of Rice Biology, China National Rice Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310006, China (X.Z., H.C., G.D., Q.Q.); andState Key Laboratory of Plant Physiology and Biochemistry, Department of Plant Sciences, College of Biological Sciences, China Agricultural University, Beijing 100193, China (L.Z., Y.F.)
| | - Fan Chen
- State Key Laboratory of Plant Genomics and National Plant Gene Research Center (J.B., Q.W., J.Zh., H.Z., Q.X., J.N., J.Zu.) and State Key Laboratory of Molecular Developmental Biology and National Plant Gene Research Center (F.C.), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China;University of Chinese Academy of Sciences, Beijing 100049, China (J.B., Q.W., H.Z., Q.X.);State Key Laboratory of Rice Biology, China National Rice Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310006, China (X.Z., H.C., G.D., Q.Q.); andState Key Laboratory of Plant Physiology and Biochemistry, Department of Plant Sciences, College of Biological Sciences, China Agricultural University, Beijing 100193, China (L.Z., Y.F.)
| | - Ying Fu
- State Key Laboratory of Plant Genomics and National Plant Gene Research Center (J.B., Q.W., J.Zh., H.Z., Q.X., J.N., J.Zu.) and State Key Laboratory of Molecular Developmental Biology and National Plant Gene Research Center (F.C.), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China;University of Chinese Academy of Sciences, Beijing 100049, China (J.B., Q.W., H.Z., Q.X.);State Key Laboratory of Rice Biology, China National Rice Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310006, China (X.Z., H.C., G.D., Q.Q.); andState Key Laboratory of Plant Physiology and Biochemistry, Department of Plant Sciences, College of Biological Sciences, China Agricultural University, Beijing 100193, China (L.Z., Y.F.)
| | - Qian Qian
- State Key Laboratory of Plant Genomics and National Plant Gene Research Center (J.B., Q.W., J.Zh., H.Z., Q.X., J.N., J.Zu.) and State Key Laboratory of Molecular Developmental Biology and National Plant Gene Research Center (F.C.), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China;University of Chinese Academy of Sciences, Beijing 100049, China (J.B., Q.W., H.Z., Q.X.);State Key Laboratory of Rice Biology, China National Rice Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310006, China (X.Z., H.C., G.D., Q.Q.); andState Key Laboratory of Plant Physiology and Biochemistry, Department of Plant Sciences, College of Biological Sciences, China Agricultural University, Beijing 100193, China (L.Z., Y.F.)
| | - Jianru Zuo
- State Key Laboratory of Plant Genomics and National Plant Gene Research Center (J.B., Q.W., J.Zh., H.Z., Q.X., J.N., J.Zu.) and State Key Laboratory of Molecular Developmental Biology and National Plant Gene Research Center (F.C.), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China;University of Chinese Academy of Sciences, Beijing 100049, China (J.B., Q.W., H.Z., Q.X.);State Key Laboratory of Rice Biology, China National Rice Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310006, China (X.Z., H.C., G.D., Q.Q.); andState Key Laboratory of Plant Physiology and Biochemistry, Department of Plant Sciences, College of Biological Sciences, China Agricultural University, Beijing 100193, China (L.Z., Y.F.)
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25
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Armour WJ, Barton DA, Law AMK, Overall RL. Differential Growth in Periclinal and Anticlinal Walls during Lobe Formation in Arabidopsis Cotyledon Pavement Cells. THE PLANT CELL 2015; 27:2484-500. [PMID: 26296967 PMCID: PMC4815096 DOI: 10.1105/tpc.114.126664] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Revised: 07/16/2015] [Accepted: 07/31/2015] [Indexed: 05/03/2023]
Abstract
Lobe development in the epidermal pavement cells of Arabidopsis thaliana cotyledons and leaves is thought to take place via tip-like growth on the concave side of lobes driven by localized concentrations of actin filaments and associated proteins, with a predicted role for cortical microtubules in establishing the direction of restricted growth at the convex side. We used homologous landmarks fixed to the outer walls of pavement cells and thin-plate spline analysis to demonstrate that lobes form by differential growth of both the anticlinal and periclinal walls. Most lobes formed within the first 24 h of the cotyledons unfurling, during the period of rapid cell expansion. Cortical microtubules adjacent to the periclinal wall were persistently enriched at the convex side of lobes during development where growth was anisotropic and were less concentrated or absent at the concave side where growth was promoted. Alternating microtubule-enriched and microtubule-free zones at the periclinal wall in neighboring cells predicted sites of new lobes. There was no particular arrangement of cortical actin filaments that could predict where lobes would form. However, drug studies demonstrate that both filamentous actin and microtubules are required for lobe formation.
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Affiliation(s)
- William J Armour
- School of Biological Sciences, University of Sydney, NSW 2006, Australia
| | - Deborah A Barton
- School of Biological Sciences, University of Sydney, NSW 2006, Australia
| | - Andrew M K Law
- School of Biological Sciences, University of Sydney, NSW 2006, Australia
| | - Robyn L Overall
- School of Biological Sciences, University of Sydney, NSW 2006, Australia
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26
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Tian J, Han L, Feng Z, Wang G, Liu W, Ma Y, Yu Y, Kong Z. Orchestration of microtubules and the actin cytoskeleton in trichome cell shape determination by a plant-unique kinesin. eLife 2015; 4. [PMID: 26287478 PMCID: PMC4574192 DOI: 10.7554/elife.09351] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 08/18/2015] [Indexed: 11/13/2022] Open
Abstract
Microtubules (MTs) and actin filaments (F-actin) function cooperatively to regulate plant cell morphogenesis. However, the mechanisms underlying the crosstalk between these two cytoskeletal systems, particularly in cell shape control, remain largely unknown. In this study, we show that introduction of the MyTH4-FERM tandem into KCBP (kinesin-like calmodulin-binding protein) during evolution conferred novel functions. The MyTH4 domain and the FERM domain in the N-terminal tail of KCBP physically bind to MTs and F-actin, respectively. During trichome morphogenesis, KCBP distributes in a specific cortical gradient and concentrates at the branching sites and the apexes of elongating branches, which lack MTs but have cortical F-actin. Further, live-cell imaging and genetic analyses revealed that KCBP acts as a hub integrating MTs and actin filaments to assemble the required cytoskeletal configuration for the unique, polarized diffuse growth pattern during trichome cell morphogenesis. Our findings provide significant insights into the mechanisms underlying cytoskeletal regulation of cell shape determination.
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Affiliation(s)
- Juan Tian
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Libo Han
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Zhidi Feng
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Guangda Wang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Weiwei Liu
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Yinping Ma
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Yanjun Yu
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Zhaosheng Kong
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
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27
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Gavrin A, Jansen V, Ivanov S, Bisseling T, Fedorova E. ARP2/3-Mediated Actin Nucleation Associated With Symbiosome Membrane Is Essential for the Development of Symbiosomes in Infected Cells of Medicago truncatula Root Nodules. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2015; 28:605-14. [PMID: 25608180 DOI: 10.1094/mpmi-12-14-0402-r] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The nitrogen-fixing rhizobia in the symbiotic infected cells of root nodules are kept in membrane compartments derived from the host cell plasma membrane, forming what are known as symbiosomes. These are maintained as individual units, with mature symbiosomes having a specific radial position in the host cell cytoplasm. The mechanisms that adapt the host cell architecture to accommodate intracellular bacteria are not clear. The intracellular organization of any cell depends heavily on the actin cytoskeleton. Dynamic rearrangement of the actin cytoskeleton is crucial for cytoplasm organization and intracellular trafficking of vesicles and organelles. A key component of the actin cytoskeleton rearrangement is the ARP2/3 complex, which nucleates new actin filaments and forms branched actin networks. To clarify the role of the ARP2/3 complex in the development of infected cells and symbiosomes, we analyzed the pattern of actin microfilaments and the functional role of ARP3 in Medicago truncatula root nodules. In infected cells, ARP3 protein and actin were spatially associated with maturing symbiosomes. Partial ARP3 silencing causes defects in symbiosome development; in particular, ARP3 silencing disrupts the final differentiation steps in functional maturation into nitrogen-fixing units.
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Affiliation(s)
- Aleksandr Gavrin
- Laboratory of Molecular Biology, Wageningen University, Droevendaalsesteeg 1, 6708PB, Wageningen, The Netherlands
| | - Veerle Jansen
- Laboratory of Molecular Biology, Wageningen University, Droevendaalsesteeg 1, 6708PB, Wageningen, The Netherlands
| | - Sergey Ivanov
- Laboratory of Molecular Biology, Wageningen University, Droevendaalsesteeg 1, 6708PB, Wageningen, The Netherlands
| | - Ton Bisseling
- Laboratory of Molecular Biology, Wageningen University, Droevendaalsesteeg 1, 6708PB, Wageningen, The Netherlands
| | - Elena Fedorova
- Laboratory of Molecular Biology, Wageningen University, Droevendaalsesteeg 1, 6708PB, Wageningen, The Netherlands
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Yanagisawa M, Desyatova AS, Belteton SA, Mallery EL, Turner JA, Szymanski DB. Patterning mechanisms of cytoskeletal and cell wall systems during leaf trichome morphogenesis. NATURE PLANTS 2015; 1:15014. [PMID: 27246881 DOI: 10.1038/nplants.2015.14] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 01/23/2015] [Indexed: 05/23/2023]
Abstract
The plant actin cytoskeleton is an unstable network of filaments that influences polarized growth through poorly understood mechanisms. Here, we used a combination of live cell imaging and finite element computational modelling of Arabidopsis trichome morphogenesis to determine how the actin and microtubule cytoskeletons cooperate to pattern the cell wall and growth. The actin-related protein (ARP)2/3 complex generates an actin meshwork that operates within a tip-localized, microtubule-depleted zone to modulate cell wall anisotropy locally. The actin meshwork also positions an actin bundle network that organizes organelle flow patterns. This activity is required to maintain cell wall thickness gradients that enable tip-biased diffuse growth. These newly discovered couplings between cytoskeletal patterns and wall textures provide important insights into the cellular mechanism of growth control in plants.
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Affiliation(s)
- Makoto Yanagisawa
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907, USA
| | - Anastasia S Desyatova
- Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA
| | - Samuel A Belteton
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907, USA
| | - Eileen L Mallery
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907, USA
| | - Joseph A Turner
- Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA
| | - Daniel B Szymanski
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907, USA
- Biological Sciences, Purdue University, West Lafayette, Indiana 47907, USA
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29
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Koudounas K, Manioudaki ME, Kourti A, Banilas G, Hatzopoulos P. Transcriptional profiling unravels potential metabolic activities of the olive leaf non-glandular trichome. FRONTIERS IN PLANT SCIENCE 2015; 6:633. [PMID: 26322070 PMCID: PMC4534801 DOI: 10.3389/fpls.2015.00633] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Accepted: 07/31/2015] [Indexed: 05/08/2023]
Abstract
The olive leaf trichomes are multicellular peltate hairs densely distributed mainly at the lower leaf epidermis. Although, non-glandular, they have gained much attention since they significantly contribute to abiotic and biotic stress tolerance of olive leaves. The exact mechanisms by which olive trichomes achieve these goals are not fully understood. They could act as mechanical barrier but they also accumulate high amounts of flavonoids among other secondary metabolites. However, little is currently known about the exact compounds they produce and the respective metabolic pathways. Here we present the first EST analysis from olive leaf trichomes by using 454-pyrosequencing. A total of 5368 unigenes were identified out of 7258 high quality reads with an average length of 262 bp. Blast search revealed that 27.5% of them had high homologies to known proteins. By using Blast2GO, 1079 unigenes (20.1%) were assigned at least one Gene Ontology (GO) term. Most of the genes were involved in cellular and metabolic processes and in binding functions followed by catalytic activity. A total of 521 transcripts were mapped to 67 KEGG pathways. Olive trichomes represent a tissue of highly unique transcriptome as per the genes involved in developmental processes and the secondary metabolism. The results indicate that mature olive trichomes are trancriptionally active, mainly through the potential production of enzymes that contribute to phenolic compounds with important roles in biotic and abiotic stress responses.
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Affiliation(s)
| | - Maria E. Manioudaki
- Department of Horticultural Genetics and Biotechnology, Mediterranean Agronomic Institute of ChaniaCrete, Greece
| | - Anna Kourti
- Department of Biotechnology, Agricultural University of AthensAthens, Greece
| | - Georgios Banilas
- Department of Oenology and Beverage Technology, Technological Educational Institute of AthensAthens, Greece
| | - Polydefkis Hatzopoulos
- Department of Biotechnology, Agricultural University of AthensAthens, Greece
- *Correspondence: Polydefkis Hatzopoulos, Department of Biotechnology, Agricultural University of Athens, Iera Odos 75, Athens 11855, Greece
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Abstract
Currently, Dual Specificity YAK1-Related Kinases (MNB/DYRK) were found in slime molds, protista, fungi, and animals, but the existence of plant homologues is still unclear. In the present study, we have identified 14 potential plant homologues with the previously unknown functions, based on the strong sequence similarity. The results of bioinformatics analysis revealed their correspondence to DYRK1A, DYRK1B, DYRK3, and DYRK4. For two plant homologues of animal DYRK1A from Physcomitrella patens and Arabidopsis thaliana spatial structures of catalytic domains were predicted, as well as their complexes with ADP and selective inhibitor d15. Comparative analysis of 3D-structures of the human DYRK1A and plant homologues, their complexes with the specific inhibitors, and results of molecular dynamics confirm their structural and functional similarity with high probability. Preliminary data indicate the presence of potential MNB/DYRK specific phosphorylation sites in such proteins associated with plant cytoskeleton as plant microtubule-associated proteins WVD2 and WDL1, and FH5 and SCAR2 involved in the organization and polarity of the actin cytoskeleton and some kinesin-like microtubule motor proteins.
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31
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Gachomo EW, Jno Baptiste L, Kefela T, Saidel WM, Kotchoni SO. The Arabidopsis CURVY1 (CVY1) gene encoding a novel receptor-like protein kinase regulates cell morphogenesis, flowering time and seed production. BMC PLANT BIOLOGY 2014; 14:221. [PMID: 25158860 PMCID: PMC4244047 DOI: 10.1186/s12870-014-0221-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Accepted: 08/05/2014] [Indexed: 05/02/2023]
Abstract
BACKGROUND A molecular-level understanding of the loss of CURVY1 (CVY1) gene expression (which encodes a member of the receptor-like protein kinase family) was investigated to gain insights into the mechanisms controlling cell morphogenesis and development in Arabidopsis thaliana. RESULTS Using a reverse genetic and cell biology approaches, we demonstrate that CVY1 is a new DISTORTED gene with similar phenotypic characterization to previously characterized ARP2/3 distorted mutants. Compared to the wild type, cvy1 mutant displayed a strong distorted trichome and altered pavement cell phenotypes. In addition, cvy1 null-mutant flowers earlier, grows faster and produces more siliques than WT and the arp2/3 mutants. The CVY1 gene is ubiquitously expressed in all tissues and seems to negatively regulate growth and yield in higher plants. CONCLUSIONS Our results suggest that CURVY1 gene participates in several biochemical pathways in Arabidopsis thaliana including (i) cell morphogenesis regulation through actin cytoskeleton functional networks, (ii) the transition of vegetative to the reproductive stage and (iii) the production of seeds.
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Affiliation(s)
- Emma W Gachomo
- />Department of Biology, Rutgers University, 315 Penn St, Camden, NJ 08102 USA
- />Center for Computational and Integrative Biology, 315 Penn St, Camden, NJ 08102 USA
| | - Lyla Jno Baptiste
- />Department of Biology, Rutgers University, 315 Penn St, Camden, NJ 08102 USA
| | - Timnit Kefela
- />Department of Biology, Rutgers University, 315 Penn St, Camden, NJ 08102 USA
| | - William M Saidel
- />Department of Biology, Rutgers University, 315 Penn St, Camden, NJ 08102 USA
- />Center for Computational and Integrative Biology, 315 Penn St, Camden, NJ 08102 USA
| | - Simeon O Kotchoni
- />Department of Biology, Rutgers University, 315 Penn St, Camden, NJ 08102 USA
- />Center for Computational and Integrative Biology, 315 Penn St, Camden, NJ 08102 USA
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32
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Sambade A, Findlay K, Schäffner AR, Lloyd CW, Buschmann H. Actin-Dependent and -Independent Functions of Cortical Microtubules in the Differentiation of Arabidopsis Leaf Trichomes. THE PLANT CELL 2014; 26:1629-1644. [PMID: 24714762 PMCID: PMC4036576 DOI: 10.1105/tpc.113.118273] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Arabidopsis thaliana tortifolía2 carries a point mutation in α-tubulin 4 and shows aberrant cortical microtubule dynamics. The microtubule defect of tortifolia2 leads to overbranching and right-handed helical growth in the single-celled leaf trichomes. Here, we use tortifolia2 to further our understanding of microtubules in plant cell differentiation. Trichomes at the branching stage show an apical ring of cortical microtubules, and our analyses support that this ring is involved in marking the prospective branch site. tortifolia2 showed ectopic microtubule bundles at this stage, consistent with a function for microtubules in selecting new branch sites. Overbranching of tortifolia2 required the C-terminal binding protein/brefeldin A-ADP ribosylated substrate protein ANGUSTIFOLIA1, and our results indicate that the angustifolia1 mutant is hypersensitive to alterations in microtubule dynamics. To analyze whether actin and microtubules cooperate in the trichome cell expansion process, we generated double mutants of tortifolia2 with distorted1, a mutant that is defective in the actin-related ARP2/3 complex. The double mutant trichomes showed a complete loss of growth anisotropy, suggesting a genetic interaction of actin and microtubules. Green fluorescent protein labeling of F-actin or microtubules in tortifolia2 distorted1 double mutants indicated that F-actin enhances microtubule dynamics and enables reorientation. Together, our results suggest actin-dependent and -independent functions of cortical microtubules in trichome differentiation.
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Affiliation(s)
- Adrian Sambade
- Department of Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, United Kingdom
| | - Kim Findlay
- Department of Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, United Kingdom
| | - Anton R Schäffner
- Institute of Biochemical Plant Pathology, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Clive W Lloyd
- Department of Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, United Kingdom
| | - Henrik Buschmann
- Department of Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, United Kingdom
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Jacques E, Verbelen JP, Vissenberg K. Review on shape formation in epidermal pavement cells of the Arabidopsis leaf. FUNCTIONAL PLANT BIOLOGY 2014; 41:914-921. [PMID: 0 DOI: 10.1071/fp13338] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Accepted: 04/22/2014] [Indexed: 05/19/2023]
Abstract
Epidermal pavement cells appear with a fascinating irregular wavy shape in the Arabidopsis thaliana leaf. This review addresses the questions of why this particular shape is produced during leaf development and how this is accomplished. To answer the first question most probably waviness offers some biomechanical benefits over other organisations. Different positions of lobe-formation are therefore explored and discussed. At the moment, however, no hard evidence that favours any one morphology is available. The latter question comprises the biomechanical accomplishment of shape and refers to the cell wall and cytoskeletal involvement herein. A current model for pavement cell development is discussed but remaining questions and pitfalls are put forward. Moreover, an overview of the genetic and biochemical regulatory pathways that are described up to date in the literature is presented.
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Ivakov A, Persson S. Plant cell shape: modulators and measurements. FRONTIERS IN PLANT SCIENCE 2013; 4:439. [PMID: 24312104 PMCID: PMC3832843 DOI: 10.3389/fpls.2013.00439] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Accepted: 10/14/2013] [Indexed: 05/19/2023]
Abstract
Plant cell shape, seen as an integrative output, is of considerable interest in various fields, such as cell wall research, cytoskeleton dynamics and biomechanics. In this review we summarize the current state of knowledge on cell shape formation in plants focusing on shape of simple cylindrical cells, as well as in complex multipolar cells such as leaf pavement cells and trichomes. We summarize established concepts as well as recent additions to the understanding of how cells construct cell walls of a given shape and the underlying processes. These processes include cell wall synthesis, activity of the actin and microtubule cytoskeletons, in particular their regulation by microtubule associated proteins, actin-related proteins, GTP'ases and their effectors, as well as the recently-elucidated roles of plant hormone signaling and vesicular membrane trafficking. We discuss some of the challenges in cell shape research with a particular emphasis on quantitative imaging and statistical analysis of shape in 2D and 3D, as well as novel developments in this area. Finally, we review recent examples of the use of novel imaging techniques and how they have contributed to our understanding of cell shape formation.
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Affiliation(s)
- Alexander Ivakov
- *Correspondence: Alexander Ivakov and Staffan Persson, Max-Planck-Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476 Potsdam, Germany e-mail: ;
| | - Staffan Persson
- *Correspondence: Alexander Ivakov and Staffan Persson, Max-Planck-Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476 Potsdam, Germany e-mail: ;
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35
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Heckman CA, Plummer HK. Filopodia as sensors. Cell Signal 2013; 25:2298-311. [PMID: 23876793 DOI: 10.1016/j.cellsig.2013.07.006] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Revised: 07/04/2013] [Accepted: 07/09/2013] [Indexed: 12/19/2022]
Abstract
Filopodia are sensors on both excitable and non-excitable cells. The sensing function is well documented in neurons and blood vessels of adult animals and is obvious during dorsal closure in embryonic development. Nerve cells extend neurites in a bidirectional fashion with growth cones at the tips where filopodia are concentrated. Their sensing of environmental cues underpins the axon's ability to "guide," bypassing non-target cells and moving toward the target to be innervated. This review focuses on the role of filopodia structure and dynamics in the detection of environmental cues, including both the extracellular matrix (ECM) and the surfaces of neighboring cells. Other protrusions including the stereocilia of the inner ear and epididymus, the invertebrate Type I mechanosensors, and the elongated processes connecting osteocytes, share certain principles of organization with the filopodia. Actin bundles, which may be inside or outside of the excitable cell, function to transduce stress from physical perturbations into ion signals. There are different ways of detecting such perturbations. Osteocyte processes contain an actin core and are physically anchored on an extracellular structure by integrins. Some Type I mechanosensors have bridge proteins that anchor microtubules to the membrane, but bundles of actin in accessory cells exert stress on this complex. Hair cells of the inner ear rely on attachments between the actin-based protrusions to activate ion channels, which then transduce signals to afferent neurons. In adherent filopodia, the focal contacts (FCs) integrated with ECM proteins through integrins may regulate integrin-coupled ion channels to achieve signal transduction. Issues that are not understood include the role of Ca(2+) influx in filopodia dynamics and how integrins coordinate or gate signals arising from perturbation of channels by environmental cues.
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Affiliation(s)
- C A Heckman
- Department of Biological Sciences, Bowling Green State University, Bowling Green, OH 43403-0212, USA.
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36
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Zhang C, Mallery E, Reagan S, Boyko VP, Kotchoni SO, Szymanski DB. The endoplasmic reticulum is a reservoir for WAVE/SCAR regulatory complex signaling in the Arabidopsis leaf. PLANT PHYSIOLOGY 2013; 162:689-706. [PMID: 23613272 PMCID: PMC3668063 DOI: 10.1104/pp.113.217422] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
During plant cell morphogenesis, signal transduction and cytoskeletal dynamics interact to locally organize the cytoplasm and define the geometry of cell expansion. The WAVE/SCAR (for WASP family verprolin homologous/suppressor of cyclic AMP receptor) regulatory complex (W/SRC) is an evolutionarily conserved heteromeric protein complex. Within the plant kingdom W/SRC is a broadly used effector that converts Rho-of-Plants (ROP)/Rac small GTPase signals into Actin-Related Protein2/3 and actin-dependent growth responses. Although the components and biochemistry of the W/SRC pathway are well understood, a basic understanding of how cells partition W/SRC into active and inactive pools is lacking. In this paper, we report that the endoplasmic reticulum (ER) is an important organelle for W/SRC regulation. We determined that a large intracellular pool of the core W/SRC subunit NAP1, like the known positive regulator of W/SRC, the DOCK family guanine nucleotide-exchange factor SPIKE1 (SPK1), localizes to the surface of the ER. The ER-associated NAP1 is inactive because it displays little colocalization with the actin network, and ER localization requires neither activating signals from SPK1 nor a physical association with its W/SRC-binding partner, SRA1. Our results indicate that in Arabidopsis (Arabidopsis thaliana) leaf pavement cells and trichomes, the ER is a reservoir for W/SRC signaling and may have a key role in the early steps of W/SRC assembly and/or activation.
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37
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Yanagisawa M, Zhang C, Szymanski DB. ARP2/3-dependent growth in the plant kingdom: SCARs for life. FRONTIERS IN PLANT SCIENCE 2013; 4:166. [PMID: 23802001 PMCID: PMC3689024 DOI: 10.3389/fpls.2013.00166] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2013] [Accepted: 05/12/2013] [Indexed: 05/18/2023]
Abstract
In the human experience SCARs (suppressor of cAMP receptors) are permanent reminders of past events, not always based on bad decisions, but always those in which an interplay of opposing forces leaves behind a clear record in the form of some permanent watery mark. During plant morphogenesis, SCARs are important proteins that reflect an unusual evolutionary outcome, in which the plant kingdom relies heavily on this single class of actin-related protein (ARP) 2/3 complex activator to dictate the time and place of actin filament nucleation. This unusually simple arrangement may serve as a permanent reminder that cell shape control in plants is fundamentally different from that of crawling cells in mammals that use the power of actin polymerization to define and maintain cell shape. In plant cells, actin filaments indirectly affect cell shape by determining the transport properties of organelles and cargo molecules that modulate the mechanical properties of the wall. It is becoming increasingly clear that polarized bundles of actin filaments operate at whole cell spatial scales to organize the cytoplasm and dictate the patterns of long-distance intracellular transport and secretion. The number of actin-binding proteins and actin filament nucleators that are known to participate in the process of actin network formation are rapidly increasing. In plants, formins and ARP2/3 are two important actin filament nucleators. This review will focus on ARP2/3, and the apparent reliance of most plant species on the SCAR/WAVE (WASP family verprolin homologous) regulatory complex as the sole pathway for ARP2/3 activation.
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Affiliation(s)
| | - Chunhua Zhang
- Department of Botany and Plant Sciences, University of CaliforniaRiverside, CA, USA
| | - Daniel B. Szymanski
- Department of Agronomy, Purdue UniversityWest Lafayette, IN, USA
- Department of Biological Sciences, Purdue UniversityWest Lafayette, IN, USA
- *Correspondence: Daniel B. Szymanski, Department of Agronomy, Purdue University, 1150 Lilly Hall of Life Sciences, West Lafayette, IN 47907-1150, USA e-mail:
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38
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Zhang C, Mallery EL, Szymanski DB. ARP2/3 localization in Arabidopsis leaf pavement cells: a diversity of intracellular pools and cytoskeletal interactions. FRONTIERS IN PLANT SCIENCE 2013; 4:238. [PMID: 23874346 PMCID: PMC3709099 DOI: 10.3389/fpls.2013.00238] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Accepted: 06/16/2013] [Indexed: 05/03/2023]
Abstract
In plant cells the actin cytoskeleton adopts many configurations, but is best understood as an unstable, interconnected track that rearranges to define the patterns of long distance transport of organelles during growth. Actin filaments do not form spontaneously; instead filament nucleators, such as the evolutionarily conserved actin-related protein (ARP) 2/3 complex, can efficiently generate new actin filament networks when in a fully activated state. A growing number of genetic experiments have shown that ARP2/3 is necessary for morphogenesis in processes that range from tip growth during root nodule formation to the diffuse polarized growth of leaf trichomes and pavement cells. Although progress has been rapid in the identification of proteins that function in series to positively regulate ARP2/3, less has been learned about the actual function of ARP2/3 in cells. In this paper, we analyze the localization of ARP2/3 in Arabidopsis leaf pavement cells. We detect a pool of ARP2/3 in the nucleus, and also find that ARP2/3 is efficiently and specifically clustered on multiple organelle surfaces and associates with both the actin filament and microtubule cytoskeletons. Our mutant analyses and ARP2/3 and actin double labeling experiments indicate that the clustering of ARP2/3 on organelle surfaces and an association with actin bundles does not necessarily reflect an active pool of ARP2/3, and instead most of the complex appears to exist as a latent organelle-associated pool.
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Affiliation(s)
- Chunhua Zhang
- Department of Agronomy, Purdue UniversityWest Lafayette, IN, USA
| | | | - Daniel B. Szymanski
- Department of Agronomy, Purdue UniversityWest Lafayette, IN, USA
- Department of Biology, Purdue UniversityWest Lafayette, IN, USA
- *Correspondence: Daniel B. Szymanski, Department of Agronomy, Purdue University, Lily Hall of Life Sciences, 915 West State Street, West Lafayette, IN 47907-2054, USA e-mail:
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Hsu CY, Adams JP, No K, Liang H, Meilan R, Pechanova O, Barakat A, Carlson JE, Page GP, Yuceer C. Overexpression of CONSTANS homologs CO1 and CO2 fails to alter normal reproductive onset and fall bud set in woody perennial poplar. PLoS One 2012; 7:e45448. [PMID: 23029015 PMCID: PMC3446887 DOI: 10.1371/journal.pone.0045448] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2012] [Accepted: 08/20/2012] [Indexed: 11/25/2022] Open
Abstract
CONSTANS (CO) is an important flowering-time gene in the photoperiodic flowering pathway of annual Arabidopsis thaliana in which overexpression of CO induces early flowering, whereas mutations in CO cause delayed flowering. The closest homologs of CO in woody perennial poplar (Populus spp.) are CO1 and CO2. A previous report showed that the CO2/FLOWERING LOCUS T1 (FT1) regulon controls the onset of reproduction in poplar, similar to what is seen with the CO/FLOWERING LOCUS T (FT) regulon in Arabidopsis. The CO2/FT1 regulon was also reported to control fall bud set. Our long-term field observations show that overexpression of CO1 and CO2 individually or together did not alter normal reproductive onset, spring bud break, or fall dormancy in poplar, but did result in smaller trees when compared with controls. Transcripts of CO1 and CO2 were normally most abundant in the growing season and rhythmic within a day, peaking at dawn. Our manipulative experiments did not provide evidence for transcriptional regulation being affected by photoperiod, light intensity, temperature, or water stress when transcripts of CO1 and CO2 were consistently measured in the morning. A genetic network analysis using overexpressing trees, microarrays, and computation demonstrated that a majority of functionally known genes downstream of CO1 and CO2 are associated with metabolic processes, which could explain their effect on tree size. In conclusion, the function of CO1 and CO2 in poplar does not appear to overlap with that of CO from Arabidopsis, nor do our data support the involvement of CO1 and CO2 in spring bud break or fall bud set.
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Affiliation(s)
- Chuan-Yu Hsu
- Department of Forestry, Mississippi State University, Mississippi State, Mississippi, United States of America
| | - Joshua P. Adams
- School of Forest Resources, University of Arkansas at Monticello, Monticello, Arkansas, United States of America
| | - Kyoungok No
- Department of Forestry, Mississippi State University, Mississippi State, Mississippi, United States of America
| | - Haiying Liang
- Department of Genetics and Biochemistry, Clemson University, Clemson, South Carolina, United States of America
| | - Richard Meilan
- Department of Forestry and Natural Resources, Purdue University, West Lafayette, Indiana, United States of America
| | - Olga Pechanova
- Department of Forestry, Mississippi State University, Mississippi State, Mississippi, United States of America
| | - Abdelali Barakat
- Department of Genetics and Biochemistry, Clemson University, Clemson, South Carolina, United States of America
- School of Forest Resources, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - John E. Carlson
- School of Forest Resources, Pennsylvania State University, University Park, Pennsylvania, United States of America
- Department of Bioenergy Science and Technology, Chonnam National University, Buk-Gu, Gwangju, South Korea
| | - Grier P. Page
- Research Triangle Institute International, Atlanta, Georgia, United States of America
| | - Cetin Yuceer
- Department of Forestry, Mississippi State University, Mississippi State, Mississippi, United States of America
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Ojangu EL, Tanner K, Pata P, Järve K, Holweg CL, Truve E, Paves H. Myosins XI-K, XI-1, and XI-2 are required for development of pavement cells, trichomes, and stigmatic papillae in Arabidopsis. BMC PLANT BIOLOGY 2012; 12:81. [PMID: 22672737 PMCID: PMC3424107 DOI: 10.1186/1471-2229-12-81] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Accepted: 05/28/2012] [Indexed: 05/18/2023]
Abstract
BACKGROUND The positioning and dynamics of vesicles and organelles, and thus the growth of plant cells, is mediated by the acto-myosin system. In Arabidopsis there are 13 class XI myosins which mediate vesicle and organelle transport in different cell types. So far the involvement of five class XI myosins in cell expansion during the shoot and root development has been shown, three of which, XI-1, XI-2, and XI-K, are essential for organelle transport. RESULTS Simultaneous depletion of Arabidopsis class XI myosins XI-K, XI-1, and XI-2 in double and triple mutant plants affected the growth of several types of epidermal cells. The size and shape of trichomes, leaf pavement cells and the elongation of the stigmatic papillae of double and triple mutant plants were affected to different extent. Reduced cell size led to significant size reduction of shoot organs in the case of triple mutant, affecting bolt formation, flowering time and fertility. Phenotype analysis revealed that the reduced fertility of triple mutant plants was caused by delayed or insufficient development of pistils. CONCLUSIONS We conclude that the class XI myosins XI-K, XI-1 and XI-2 have partially redundant roles in the growth of shoot epidermis. Myosin XI-K plays more important role whereas myosins XI-1 and XI-2 have minor roles in the determination of size and shape of epidermal cells, because the absence of these two myosins is compensated by XI-K. Co-operation between myosins XI-K and XI-2 appears to play an important role in these processes.
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Affiliation(s)
- Eve-Ly Ojangu
- Department of Gene Technology, Tallinn University of Technology, Akadeemia tee 15, 12618, Tallinn, Estonia
| | - Krista Tanner
- Department of Gene Technology, Tallinn University of Technology, Akadeemia tee 15, 12618, Tallinn, Estonia
| | - Pille Pata
- Department of Gene Technology, Tallinn University of Technology, Akadeemia tee 15, 12618, Tallinn, Estonia
| | - Kristel Järve
- Department of Gene Technology, Tallinn University of Technology, Akadeemia tee 15, 12618, Tallinn, Estonia
| | - Carola L Holweg
- Nachhaltigkeits-Projekte, Alte Str. 13, 79249, Merzhausen, Germany
| | - Erkki Truve
- Department of Gene Technology, Tallinn University of Technology, Akadeemia tee 15, 12618, Tallinn, Estonia
| | - Heiti Paves
- Department of Gene Technology, Tallinn University of Technology, Akadeemia tee 15, 12618, Tallinn, Estonia
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Dyachok J, Zhu L, Liao F, He J, Huq E, Blancaflor EB. SCAR mediates light-induced root elongation in Arabidopsis through photoreceptors and proteasomes. THE PLANT CELL 2011; 23:3610-26. [PMID: 21972261 PMCID: PMC3229138 DOI: 10.1105/tpc.111.088823] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Revised: 09/09/2011] [Accepted: 09/17/2011] [Indexed: 05/18/2023]
Abstract
The ARP2/3 complex, a highly conserved nucleator of F-actin, and its activator, the SCAR complex, are essential for growth in plants and animals. In this article, we present a pathway through which roots of Arabidopsis thaliana directly perceive light to promote their elongation. The ARP2/3-SCAR complex and the maintenance of longitudinally aligned F-actin arrays are crucial components of this pathway. The involvement of the ARP2/3-SCAR complex in light-regulated root growth is supported by our finding that mutants of the SCAR complex subunit BRK1/HSPC300, or other individual subunits of the ARP2/3-SCAR complex, showed a dramatic inhibition of root elongation in the light, which mirrored reduced growth of wild-type roots in the dark. SCAR1 degradation in dark-grown wild-type roots by constitutive photomorphogenic 1 (COP1) E3 ligase and 26S proteasome accompanied the loss of longitudinal F-actin and reduced root growth. Light perceived by the root photoreceptors, cryptochrome and phytochrome, suppressed COP1-mediated SCAR1 degradation. Taken together, our data provide a biochemical explanation for light-induced promotion of root elongation by the ARP2/3-SCAR complex.
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Affiliation(s)
- Julia Dyachok
- Plant Biology Division, The Samuel Roberts Noble Foundation, Ardmore, Oklahoma 73401
| | - Ling Zhu
- Section of Molecular Cell and Developmental Biology and the Institute for Cellular and Molecular Biology, University of Texas, Austin, Texas 78712
| | - Fuqi Liao
- Plant Biology Division, The Samuel Roberts Noble Foundation, Ardmore, Oklahoma 73401
| | - Ji He
- Plant Biology Division, The Samuel Roberts Noble Foundation, Ardmore, Oklahoma 73401
| | - Enamul Huq
- Section of Molecular Cell and Developmental Biology and the Institute for Cellular and Molecular Biology, University of Texas, Austin, Texas 78712
| | - Elison B. Blancaflor
- Plant Biology Division, The Samuel Roberts Noble Foundation, Ardmore, Oklahoma 73401
- Address correspondence to
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The branched actin nucleator Arp2/3 promotes nuclear migrations and cell polarity in the C. elegans zygote. Dev Biol 2011; 357:356-69. [PMID: 21798253 DOI: 10.1016/j.ydbio.2011.07.008] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Revised: 06/17/2011] [Accepted: 07/06/2011] [Indexed: 01/08/2023]
Abstract
Regulated movements of the nucleus are essential during zygote formation, cell migrations, and differentiation of neurons. The nucleus moves along microtubules (MTs) and is repositioned on F-actin at the cellular cortex. Two families of nuclear envelope proteins, SUN and KASH, link the nucleus to the actin and MT cytoskeletons during nuclear movements. However, the role of actin nucleators in nuclear migration and positioning is poorly understood. We show that the branched actin nucleator, Arp2/3, affects nuclear movements throughout embryonic and larval development in C. elegans, including nuclear migrations in epidermal cells and neuronal precursors. In one-cell embryos the migration of the male pronucleus to meet the female pronucleus after fertilization requires Arp2/3. Loss of Arp2/3 or its activators changes the dynamics of non-muscle myosin, NMY-2, and alters the cortical accumulation of posterior PAR proteins. Reduced establishment of the posterior microtubule cytoskeleton in Arp2/3 mutants correlates with reduced male pronuclear migration. The UNC-84/SUN nuclear envelope protein that links the nucleus to the MT and actin cytoskeleton is known to regulate later nuclear migrations. We show here it also positions the male pronucleus. These studies demonstrate a global role for Arp2/3 in nuclear migrations. In the C. elegans one-cell embryo Arp2/3 promotes the establishment of anterior/posterior polarity and promotes MT growth that propels the anterior migration of the male pronucleus. In contrast with previous studies emphasizing pulling forces on the male pronucleus, we propose that robust MT nucleation pushes the male pronucleus anteriorly to join the female pronucleus.
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Kryvych S, Kleessen S, Ebert B, Kersten B, Fisahn J. Proteomics - The key to understanding systems biology of Arabidopsis trichomes. PHYTOCHEMISTRY 2011; 72:1061-1070. [PMID: 20952039 DOI: 10.1016/j.phytochem.2010.09.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2010] [Revised: 09/09/2010] [Accepted: 09/17/2010] [Indexed: 05/30/2023]
Abstract
Every multicellular organism consists of numerous organs, tissues and specific cell types. To gain detailed knowledge about the morphogenesis of these complex structures, it is inevitable to advance biochemical analyses to ultimate spatial and temporal resolution since individual cell types contribute differently to the overall performance of living objects. Single cell sampling combined with systems biological approaches was recently applied to investigations of Arabidopsis thaliana trichomes (leaf hairs). These are single celled structures that provide ideal model systems to address various aspects of plant cell development and differentiation at the level of individual cells. A previously suggested function of trichomes in plant stress responses could thus be confirmed. Furthermore, trichome-specific "omics" data collected in several laboratories are mutually conclusive which demonstrates the applicability of systems biological approaches at the single cell level.
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Affiliation(s)
- Sergiy Kryvych
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
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High-resolution X-ray structure of the trimeric Scar/WAVE-complex precursor Brk1. PLoS One 2011; 6:e21327. [PMID: 21701600 PMCID: PMC3119050 DOI: 10.1371/journal.pone.0021327] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2011] [Accepted: 05/30/2011] [Indexed: 01/08/2023] Open
Abstract
The Scar/WAVE-complex links upstream Rho-GTPase signaling to the activation of the conserved Arp2/3-complex. Scar/WAVE-induced and Arp2/3-complex-mediated actin nucleation is crucial for actin assembly in protruding lamellipodia to drive cell migration. The heteropentameric Scar/WAVE-complex is composed of Scar/WAVE, Abi, Nap, Pir and a small polypeptide Brk1/HSPC300, and recent work suggested that free Brk1 serves as a homooligomeric precursor in the assembly of this complex. Here we characterized the Brk1 trimer from Dictyostelium by analytical ultracentrifugation and gelfiltration. We show for the first time its dissociation at concentrations in the nanomolar range as well as an exchange of subunits within different DdBrk1 containing complexes. Moreover, we determined the three-dimensional structure of DdBrk1 at 1.5 Å resolution by X-ray crystallography. Three chains of DdBrk1 are associated with each other forming a parallel triple coiled-coil bundle. Notably, this structure is highly similar to the heterotrimeric α-helical bundle of HSPC300/WAVE1/Abi2 within the human Scar/WAVE-complex. This finding, together with the fact that Brk1 is collectively sandwiched by the remaining subunits and also constitutes the main subunit connecting the triple-coil domain of the HSPC300/WAVE1/Abi2/ heterotrimer to Sra1(Pir1), implies a critical function of this subunit in the assembly process of the entire Scar/WAVE-complex.
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Tang Z, Zhang L, Yang D, Zhao C, Zheng Y. Cold stress contributes to aberrant cytokinesis during male meiosis I in a wheat thermosensitive genic male sterile line. PLANT, CELL & ENVIRONMENT 2011; 34:389-405. [PMID: 21062315 DOI: 10.1111/j.1365-3040.2010.02250.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The male sterility of a wheat thermosensitive genic male sterile (TGMS) line is strictly controlled by temperature. When the TGMS line BS366 was exposed to 10 °C from the pollen mother cell stage to the meiosis stage, a few pollen grains were formed and devoid of starch. We report here a large-scale transcriptomic study using the Affymetrix wheat GeneChip to follow gene expression in BS366 line anthers in response to cold stress. Notably, many cytoskeletal signaling components were gradually induced in response to cold stress in BS366 line anthers. However, the cytoskeleton-associated genes that play key roles in the dynamic organization of the cytoskeleton were dramatically repressed. Histological studies revealed that the separation of dyads occurred abnormally during male meiosis I, indicating defective male meiotic cytokinesis. Fluorescence labelling and subcellular histological observations revealed that the phragmoplast was defectively formed and the cell plate was abnormally assembled during meiosis I under cold stress. Based on the transcriptomic analysis and observations of characterized histological changes, our results suggest that cold stress repressed transcription of cytoskeleton dynamic factors and subsequently caused the defective cytokinesis during meiosis I. The results may explain the male sterility caused by low temperature in wheat TGMS lines.
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Affiliation(s)
- Zonghui Tang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
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Miyahara A, Richens J, Starker C, Morieri G, Smith L, Long S, Downie JA, Oldroyd GED. Conservation in function of a SCAR/WAVE component during infection thread and root hair growth in Medicago truncatula. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2010; 23:1553-62. [PMID: 20731530 DOI: 10.1094/mpmi-06-10-0144] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Nitrogen-fixing symbioses of plants are often associated with bacterially infected nodules where nitrogen fixation occurs. The plant host facilitates bacterial infection with the formation of infection threads, unique structures associated with these symbioses, which are invaginations of the host cell with the capability of traversing cellular junctions. Here, we show that the infection thread shares mechanistic similarities to polar-growing cells, because the required for infection thread (RIT) locus of Medicago truncatula has roles in root-hair, trichome, and infection-thread growth. We show that RIT encodes the M. truncatula ortholog of NAP1, a component of the SCAR/WAVE (suppressor of cAMP receptor/WASP-family verprolin homologous protein) complex that regulates actin polymerization, through the activation of ARP2/3. NAP1 of Arabidopsis thaliana functions equivalently to the M. truncatula gene, indicating that the mode of action of NAP1 is functionally conserved across species and that legumes have not evolved a unique functionality for NAP1 during rhizobial colonization. This work highlights the surprising commonality between polar-growing cells and a polar-growing cellular intrusion and reveals important insights into the formation and maintenance of infection-thread development.
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Affiliation(s)
- Akira Miyahara
- Department of Disease and Stress Biology, John Innes Centre, Norwich Research Park, Colney Lane, Norwich, NR4 7UH, UK
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Jörgens CI, Grünewald N, Hülskamp M, Uhrig JF. A role for ABIL3 in plant cell morphogenesis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2010; 62:925-35. [PMID: 20345606 DOI: 10.1111/j.1365-313x.2010.04210.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Actin nucleation facilitated by the ARP2/3 complex plays a central role in plant cell shape development. The molecular characterization of the distorted class of trichome mutants has recently revealed the SCAR/WAVE complex as an essential upstream activator of ARP2/3 function in plants. The SCAR/WAVE complex is conserved from animals to plants and, generally, is composed of the five subunits SCAR/WAVE, PIR121, NAP125, BRICK and ABI. In plants, four of the five subunits have been shown to participate in trichome and pavement morphogenesis. Plant ABI-like proteins (ABIL), however, which constitute a small four-member protein family in Arabidopsis thaliana, have not been characterized functionally, so far. Here we demonstrate that microRNA knock-down of the ABIL3 gene leads to a distorted trichome phenotype reminiscent of ARP2/3 mutant phenotypes and consistent with a crucial role of the ABIL3 protein in an ARP2/3-activating SCAR/WAVE complex. In contrast to ARP2/3 mutants, however, the ABIL3 knock-down stimulated cell elongation in the root, indicating distinct functions of the ABIL3 protein in different tissues. Furthermore, we provide evidence that ABIL3 associates with microtubules in vivo, opening up the intriguing possibility that ABI-like proteins have a function in linking SCAR/WAVE-dependent actin nucleation with organization of the microtubule cytoskeleton.
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Affiliation(s)
- Cordula I Jörgens
- Botanical Institute III, University of Köln, Gyrhofstr. 15, 50931 Köln, Germany
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Allelic variation in cell wall candidate genes affecting solid wood properties in natural populations and land races of Pinus radiata. Genetics 2010; 185:1477-87. [PMID: 20498299 DOI: 10.1534/genetics.110.116582] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Forest trees are ideally suited to association mapping due to their high levels of diversity and low genomic linkage disequilibrium. Using an association mapping approach, single-nucleotide polymorphism (SNP) markers influencing quantitative variation in wood quality were identified in a natural population of Pinus radiata. Of 149 sites examined, 10 demonstrated significant associations (P < 0.05, q < 0.1) with one or more traits after accounting for population structure and experimentwise error. Without accounting for marker interactions, phenotypic variation attributed to individual SNPs ranged from 2 to 6.5%. Undesirable negative correlations between wood quality and growth were not observed, indicating potential to break negative correlations by selecting for individual SNPs in breeding programs. Markers that yielded significant associations were reexamined in an Australian land race. SNPs from three genes (PAL1, PCBER, and SUSY) yielded significant associations. Importantly, associations with two of these genes validated associations with density previously observed in the discovery population. In both cases, decreased wood density was associated with the minor allele, suggesting that these SNPs may be under weak negative purifying selection for density in the natural populations. These results demonstrate the utility of LD mapping to detect associations, even when the power to detect SNPs with small effect is anticipated to be low.
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50
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Kotchoni SO, Zakharova T, Mallery EL, Le J, El-Assal SED, Szymanski DB. The association of the Arabidopsis actin-related protein2/3 complex with cell membranes is linked to its assembly status but not its activation. PLANT PHYSIOLOGY 2009; 151:2095-109. [PMID: 19801398 PMCID: PMC2785977 DOI: 10.1104/pp.109.143859] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2009] [Accepted: 09/28/2009] [Indexed: 05/18/2023]
Abstract
In growing plant cells, the combined activities of the cytoskeleton, endomembrane, and cell wall biosynthetic systems organize the cytoplasm and define the architecture and growth properties of the cell. These biosynthetic machineries efficiently synthesize, deliver, and recycle the raw materials that support cell expansion. The precise roles of the actin cytoskeleton in these processes are unclear. Certainly, bundles of actin filaments position organelles and are a substrate for long-distance intracellular transport, but the functional linkages between dynamic actin filament arrays and the cell growth machinery are poorly understood. The Arabidopsis (Arabidopsis thaliana) "distorted group" mutants have defined protein complexes that appear to generate and convert small GTPase signals into an Actin-Related Protein2/3 (ARP2/3)-dependent actin filament nucleation response. However, direct biochemical knowledge about Arabidopsis ARP2/3 and its cellular distribution is lacking. In this paper, we provide biochemical evidence for a plant ARP2/3. The plant complex utilizes a conserved assembly mechanism. ARPC4 is the most critical core subunit that controls the assembly and steady-state levels of the complex. ARP2/3 in other systems is believed to be mostly a soluble complex that is locally recruited and activated. Unexpectedly, we find that Arabidopsis ARP2/3 interacts strongly with cell membranes. Membrane binding is linked to complex assembly status and not to the extent to which it is activated. Mutant analyses implicate ARP2 as an important subunit for membrane association.
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