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Zhang C, Chang W, Li X, Yang B, Zhang L, Xiao Z, Li J, Lu K. Transcriptome and Small RNA Sequencing Reveal the Mechanisms Regulating Harvest Index in Brassica napus. FRONTIERS IN PLANT SCIENCE 2022; 13:855486. [PMID: 35444672 PMCID: PMC9014204 DOI: 10.3389/fpls.2022.855486] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Accepted: 02/22/2022] [Indexed: 06/14/2023]
Abstract
Harvest index (HI), the ratio of harvested seed weight to total aboveground biomass weight, is an economically critical value reflecting the convergence of complex agronomic traits. HI values in rapeseed (Brassica napus) remain much lower than in other major crops, and the underlying regulatory network is largely unknown. In this study, we performed mRNA and small RNA sequencing to reveal the mechanisms shaping HI in B. napus during the seed-filling stage. A total of 8,410 differentially expressed genes (DEGs) between high-HI and low-HI accessions in four tissues (silique pericarp, seed, leaves, and stem) were identified. Combining with co-expression network, 72 gene modules were identified, and a key gene BnaSTY46 was found to participate in retarded establishment of photosynthetic capacity to influence HI. Further research found that the genes involved in circadian rhythms and response to stimulus may play important roles in HI and that their transcript levels were modulated by differentially expressed microRNAs (DEMs), and we identified 903 microRNAs (miRNAs), including 46 known miRNAs and 857 novel miRNAs. Furthermore, transporter activity-related genes were critical to enhancing HI in good cultivation environments. Of 903 miRNAs, we found that the bna-miR396-Bna.A06SRp34a/Bna.A01EMB3119 pair may control the seed development and the accumulation of storage compounds, thus contributing to higher HI. Our findings uncovered the underlying complex regulatory network behind HI and offer potential approaches to rapeseed improvement.
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Affiliation(s)
- Chao Zhang
- Chongqing Rapeseed Engineering Research Center, College of Agronomy and Biotechnology, Southwest University, Chongqing, China
- Academy of Agricultural Sciences, Southwest University, Chongqing, China
- Oil Research Institute of Guizhou Province, Guizhou Academy of Agricultural Sciences, Guiyang, China
| | - Wei Chang
- Chongqing Rapeseed Engineering Research Center, College of Agronomy and Biotechnology, Southwest University, Chongqing, China
- Academy of Agricultural Sciences, Southwest University, Chongqing, China
| | - Xiaodong Li
- Chongqing Rapeseed Engineering Research Center, College of Agronomy and Biotechnology, Southwest University, Chongqing, China
- Academy of Agricultural Sciences, Southwest University, Chongqing, China
| | - Bo Yang
- Chongqing Rapeseed Engineering Research Center, College of Agronomy and Biotechnology, Southwest University, Chongqing, China
- Academy of Agricultural Sciences, Southwest University, Chongqing, China
| | - Liyuan Zhang
- Chongqing Rapeseed Engineering Research Center, College of Agronomy and Biotechnology, Southwest University, Chongqing, China
- Academy of Agricultural Sciences, Southwest University, Chongqing, China
| | - Zhongchun Xiao
- Chongqing Rapeseed Engineering Research Center, College of Agronomy and Biotechnology, Southwest University, Chongqing, China
- Academy of Agricultural Sciences, Southwest University, Chongqing, China
| | - Jiana Li
- Chongqing Rapeseed Engineering Research Center, College of Agronomy and Biotechnology, Southwest University, Chongqing, China
- Academy of Agricultural Sciences, Southwest University, Chongqing, China
- Engineering Research Center of South Upland Agriculture, Ministry of Education, Chongqing, China
| | - Kun Lu
- Chongqing Rapeseed Engineering Research Center, College of Agronomy and Biotechnology, Southwest University, Chongqing, China
- Academy of Agricultural Sciences, Southwest University, Chongqing, China
- Engineering Research Center of South Upland Agriculture, Ministry of Education, Chongqing, China
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2
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Dumais J. Mechanics and hydraulics of pollen tube growth. THE NEW PHYTOLOGIST 2021; 232:1549-1565. [PMID: 34492127 DOI: 10.1111/nph.17722] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Accepted: 08/21/2021] [Indexed: 06/13/2023]
Abstract
All kingdoms of life have evolved tip-growing cells able to mine their environment or deliver cargo to remote targets. The basic cellular processes supporting these functions are understood in increasing detail, but the multiple interactions between them lead to complex responses that require quantitative models to be disentangled. Here, I review the equations that capture the fundamental interactions between wall mechanics and cell hydraulics starting with a detailed presentation of James Lockhart's seminal model. The homeostatic feedbacks needed to maintain a steady tip velocity are then shown to offer a credible explanation for the pulsatile growth observed in some tip-growing cells. Turgor pressure emerges as a central variable whose role in the morphogenetic process has been a source of controversy for more than 50 yr. I argue that recasting Lockhart's work as a process of chemical stress relaxation can clarify how cells control tip growth and help us internalise the important but passive role played by turgor pressure in the morphogenetic process.
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Affiliation(s)
- Jacques Dumais
- Faculty of Engineering and Sciences, Universidad Adolfo Ibáñez, Av. Padre Hurtado 750, Viña del Mar, Region of Valparaíso, Chile
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3
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Durand M, Cohen D, Aubry N, Buré C, Tomášková I, Hummel I, Brendel O, Le Thiec D. Element content and expression of genes of interest in guard cells are connected to spatiotemporal variations in stomatal conductance. PLANT, CELL & ENVIRONMENT 2020; 43:87-102. [PMID: 31423592 DOI: 10.1111/pce.13644] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 08/11/2019] [Indexed: 05/23/2023]
Abstract
Element content and expression of genes of interest on single cell types, such as stomata, provide valuable insights into their specific physiology, improving our understanding of leaf gas exchange regulation. We investigated how far differences in stomatal conductance (gs ) can be ascribed to changes in guard cells functioning in amphistomateous leaves. gs was measured during the day on both leaf sides, on well-watered and drought-stressed trees (two Populus euramericana Moench and two Populus nigra L. genotypes). In parallel, guard cells were dissected for element content and gene expressions analyses. Both were strongly arranged according to genotype, and drought had the lowest impact overall. Normalizing the data by genotype highlighted a structure on the basis of leaf sides and time of day both for element content and gene expression. Guard cells magnesium, phosphorus, and chlorine were the most abundant on the abaxial side in the morning, where gs was at the highest. In contrast, genes encoding H+ -ATPase and aquaporins were usually more abundant in the afternoon, whereas genes encoding Ca2+ -vacuolar antiporters, K+ channels, and ABA-related genes were in general more abundant on the adaxial side. Our work highlights the unique physiology of each leaf side and their analogous rhythmicity through the day.
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Affiliation(s)
- Maxime Durand
- Inra, Université de Lorraine, AgroParisTech, SILVA, F-54280, Champenoux, France
| | - David Cohen
- Inra, Université de Lorraine, AgroParisTech, SILVA, F-54280, Champenoux, France
| | - Nathalie Aubry
- Inra, Université de Lorraine, AgroParisTech, SILVA, F-54280, Champenoux, France
| | - Cyril Buré
- Inra, Université de Lorraine, AgroParisTech, SILVA, F-54280, Champenoux, France
| | - Ivana Tomášková
- Department of Genetics and Physiology of Forest Trees, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences Prague, Prague, 165 00, Czech Republic
| | - Irène Hummel
- Inra, Université de Lorraine, AgroParisTech, SILVA, F-54280, Champenoux, France
| | - Oliver Brendel
- Inra, Université de Lorraine, AgroParisTech, SILVA, F-54280, Champenoux, France
| | - Didier Le Thiec
- Inra, Université de Lorraine, AgroParisTech, SILVA, F-54280, Champenoux, France
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4
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Fabrice TN, Vogler H, Draeger C, Munglani G, Gupta S, Herger AG, Knox P, Grossniklaus U, Ringli C. LRX Proteins Play a Crucial Role in Pollen Grain and Pollen Tube Cell Wall Development. PLANT PHYSIOLOGY 2018; 176:1981-1992. [PMID: 29247121 PMCID: PMC5841697 DOI: 10.1104/pp.17.01374] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 12/14/2017] [Indexed: 05/20/2023]
Abstract
Leu-rich repeat extensins (LRXs) are chimeric proteins containing an N-terminal Leu-rich repeat (LRR) and a C-terminal extensin domain. LRXs are involved in cell wall formation in vegetative tissues and required for plant growth. However, the nature of their role in these cellular processes remains to be elucidated. Here, we used a combination of molecular techniques, light microscopy, and transmission electron microscopy to characterize mutants of pollen-expressed LRXs in Arabidopsis (Arabidopsisthaliana). Mutations in multiple pollen-expressed lrx genes cause severe defects in pollen germination and pollen tube growth, resulting in a reduced seed set. Physiological experiments demonstrate that manipulating Ca2+ availability partially suppresses the pollen tube growth defects, suggesting that LRX proteins influence Ca2+-related processes. Furthermore, we show that LRX protein localizes to the cell wall, and its LRR-domain (which likely mediates protein-protein interactions) is associated with the plasma membrane. Mechanical analyses by cellular force microscopy and finite element method-based modeling revealed significant changes in the material properties of the cell wall and the fine-tuning of cellular biophysical parameters in the mutants compared to the wild type. The results indicate that LRX proteins might play a role in cell wall-plasma membrane communication, influencing cell wall formation and cellular mechanics.
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Affiliation(s)
- Tohnyui Ndinyanka Fabrice
- Institute of Plant and Microbial Biology and Zurich-Basel Plant Science Center, University of Zurich, 8008 Zurich, Switzerland
| | - Hannes Vogler
- Institute of Plant and Microbial Biology and Zurich-Basel Plant Science Center, University of Zurich, 8008 Zurich, Switzerland
| | - Christian Draeger
- Institute of Plant and Microbial Biology and Zurich-Basel Plant Science Center, University of Zurich, 8008 Zurich, Switzerland
| | - Gautam Munglani
- Institute of Plant and Microbial Biology and Zurich-Basel Plant Science Center, University of Zurich, 8008 Zurich, Switzerland
- Computational Physics for Engineering Materials Group, Institute for Building Materials, ETH Zürich, 8093 Zurich, Switzerland
| | - Shibu Gupta
- Institute of Plant and Microbial Biology and Zurich-Basel Plant Science Center, University of Zurich, 8008 Zurich, Switzerland
| | - Aline G Herger
- Institute of Plant and Microbial Biology and Zurich-Basel Plant Science Center, University of Zurich, 8008 Zurich, Switzerland
| | - Paul Knox
- Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, LS2 9JT Leeds, United Kingdom
| | - Ueli Grossniklaus
- Institute of Plant and Microbial Biology and Zurich-Basel Plant Science Center, University of Zurich, 8008 Zurich, Switzerland
| | - Christoph Ringli
- Institute of Plant and Microbial Biology and Zurich-Basel Plant Science Center, University of Zurich, 8008 Zurich, Switzerland
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Zhao M, Tan HT, Scharwies J, Levin K, Evans JR, Tyerman SD. Association between water and carbon dioxide transport in leaf plasma membranes: assessing the role of aquaporins. PLANT, CELL & ENVIRONMENT 2017; 40:789-801. [PMID: 27620674 DOI: 10.1111/pce.12830] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 09/05/2016] [Accepted: 09/07/2016] [Indexed: 05/24/2023]
Abstract
The role of some aquaporins as CO2 permeable channels has been controversial. Low CO2 permeability of plant membranes has been criticized because of unstirred layers and other limitations. Here we measured both water and CO2 permeability (Pos , PCO2 ) using stopped flow on plasma membrane vesicles (pmv) isolated from Pisum sativum (pea) and Arabidopsis thaliana leaves. We excluded the chemical limitation of carbonic anhydrase (CA) in the vesicle acidification technique for PCO2 using different temperatures and CA concentrations. Unstirred layers were excluded based on small vesicle size and the positive correlation between vesicle diameter and PCO2 . We observed high aquaporin activity (Pos 0.06 to 0.22 cm s-1 ) for pea pmv based on all the criteria for their function using inhibitors and temperature dependence. Inhibitors of Pos did not alter PCO2 . PCO2 ranged from 0.001 to 0.012 cm s-1 (mean 0.0079 + 0.0007 cm s-1 ) with activation energy of 30.2 kJ mol-1 . Intrinsic variation between pmv batches from normally grown or stressed plants revealed a weak (R2 = 0.27) positive linear correlation between Pos and PCO2 . Despite the low PCO2 , aquaporins may facilitate CO2 transport across plasma membranes, but probably via a different pathway than for water.
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Affiliation(s)
- Manchun Zhao
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen Osmond, South Australia, 5064, Australia
| | - Hwei-Ting Tan
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen Osmond, South Australia, 5064, Australia
| | - Johannes Scharwies
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen Osmond, South Australia, 5064, Australia
| | - Kara Levin
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen Osmond, South Australia, 5064, Australia
| | - John R Evans
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, 0200, Australia
| | - Stephen D Tyerman
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen Osmond, South Australia, 5064, Australia
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6
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Li S, Dong H, Pei W, Liu C, Zhang S, Sun T, Xue X, Ren H. LlFH1-mediated interaction between actin fringe and exocytic vesicles is involved in pollen tube tip growth. THE NEW PHYTOLOGIST 2017; 214:745-761. [PMID: 28092406 DOI: 10.1111/nph.14395] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 11/16/2016] [Indexed: 05/15/2023]
Abstract
Pollen tube tip growth is an extreme form of polarized cell growth, which requires polarized exocytosis based on a dynamic actin cytoskeleton. However, the molecular basis for the connection between actin filaments and exocytic vesicles is unclear. Here, we identified a Lilium longiflorum pollen-specific formin (LlFH1) and found that it localized at the apical vesicles and plasma membrane (PM). Overexpression of LlFH1 induced excessive actin cables in the tube tip region, and downregulation of LlFH1 eliminated the actin fringe. Fluorescence recovery after photobleaching (FRAP) analysis revealed that LlFH1-labeled exocytic vesicles exhibited an initial accumulation at the shoulder of the apex and coincided with the leading edge of the actin fringe. Time-lapse analysis suggested that nascent actin filaments followed the emergence of the apical vesicles, implying that LlFH1 at apical vesicles could initiate actin polymerization. Biochemical assays showed that LlFH1 FH1FH2 could nucleate actin polymerization, but then capped the actin filament at the barbed end and inhibited its elongation. However, in the presence of lily profilins, LlFH1 FH1FH2 could accelerate barbed-end actin elongation. In addition, LlFH1 FH1FH2 was able to bundle actin filaments. Thus, we propose that LlFH1 and profilin coordinate the interaction between the actin fringe and exocytic vesicle trafficking during pollen tube growth of lily.
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Affiliation(s)
- Shanwei Li
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education and College of Life Science, Beijing Normal University, Beijing, 100875, China
| | - Huaijian Dong
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education and College of Life Science, Beijing Normal University, Beijing, 100875, China
| | - Weike Pei
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education and College of Life Science, Beijing Normal University, Beijing, 100875, China
| | - Chaonan Liu
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education and College of Life Science, Beijing Normal University, Beijing, 100875, China
| | - Sha Zhang
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education and College of Life Science, Beijing Normal University, Beijing, 100875, China
| | - Tiantian Sun
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education and College of Life Science, Beijing Normal University, Beijing, 100875, China
| | - Xiuhua Xue
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education and College of Life Science, Beijing Normal University, Beijing, 100875, China
| | - Haiyun Ren
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education and College of Life Science, Beijing Normal University, Beijing, 100875, China
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7
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Michard E, Simon AA, Tavares B, Wudick MM, Feijó JA. Signaling with Ions: The Keystone for Apical Cell Growth and Morphogenesis in Pollen Tubes. PLANT PHYSIOLOGY 2017; 173:91-111. [PMID: 27895207 PMCID: PMC5210754 DOI: 10.1104/pp.16.01561] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 11/19/2016] [Indexed: 05/18/2023]
Abstract
Ion homeostasis and signaling are crucial to regulate pollen tube growth and morphogenesis and affect upstream membrane transporters and downstream targets.
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Affiliation(s)
- Erwan Michard
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742-5815 (E.M., A.A.S., M.M.W., J.A.F.); and
- Instituto Gulbenkian de Ciência, Oeiras 2780-901, Portugal (B.T.)
| | - Alexander A Simon
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742-5815 (E.M., A.A.S., M.M.W., J.A.F.); and
- Instituto Gulbenkian de Ciência, Oeiras 2780-901, Portugal (B.T.)
| | - Bárbara Tavares
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742-5815 (E.M., A.A.S., M.M.W., J.A.F.); and
- Instituto Gulbenkian de Ciência, Oeiras 2780-901, Portugal (B.T.)
| | - Michael M Wudick
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742-5815 (E.M., A.A.S., M.M.W., J.A.F.); and
- Instituto Gulbenkian de Ciência, Oeiras 2780-901, Portugal (B.T.)
| | - José A Feijó
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742-5815 (E.M., A.A.S., M.M.W., J.A.F.); and
- Instituto Gulbenkian de Ciência, Oeiras 2780-901, Portugal (B.T.)
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Pérez Di Giorgio JA, Soto GC, Muschietti JP, Amodeo G. Pollen Aquaporins: The Solute Factor. FRONTIERS IN PLANT SCIENCE 2016; 7:1659. [PMID: 27881985 PMCID: PMC5101680 DOI: 10.3389/fpls.2016.01659] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 10/21/2016] [Indexed: 05/12/2023]
Abstract
In the recent years, the biophysical properties and presumed physiological role of aquaporins (AQPs) have been expanded to specialized cells where water and solute exchange are crucial traits. Complex but unique processes such as stomatal movement or pollen hydration and germination have been addressed not only by identifying the specific AQP involved but also by studying how these proteins integrate and coordinate cellular activities and functions. In this review, we referred specifically to pollen-specific AQPs and analyzed what has been assumed in terms of transport properties and what has been found in terms of their physiological role. Unlike that in many other cells, the AQP machinery in mature pollen lacks plasma membrane intrinsic proteins, which are extensively studied for their high water capacity exchange. Instead, a variety of TIPs and NIPs are expressed in pollen. These findings have altered the initial understanding of AQPs and water exchange to consider specific and diverse solutes that might be critical to sustaining pollen's success. The spatial and temporal distribution of the pollen AQPs also reflects a regulatory mechanism that allowing a properly adjusting water and solute exchange.
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Affiliation(s)
- Juliana A. Pérez Di Giorgio
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular – Consejo Nacional de Investigaciones Científicas y TécnicasBuenos Aires, Argentina
| | - Gabriela C. Soto
- Instituto de Genética Ewald A. Favret – Centro de Investigación en Ciencias Veterinarias y Agronómicas – Instituto Nacional de Tecnología Agropecuaria – Consejo Nacional de Investigaciones Científicas y TécnicasBuenos Aires, Argentina
| | - Jorge P. Muschietti
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular – Consejo Nacional de Investigaciones Científicas y TécnicasBuenos Aires, Argentina
- Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos AiresBuenos Aires, Argentina
| | - Gabriela Amodeo
- Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos AiresBuenos Aires, Argentina
- Instituto de Biodiversidad y Biología Experimental y Aplicada – Universidad de Buenos Aires–Consejo Nacional de Investigaciones Científicas y TécnicasBuenos Aires, Argentina
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Di Giorgio JAP, Bienert GP, Ayub ND, Yaneff A, Barberini ML, Mecchia MA, Amodeo G, Soto GC, Muschietti JP. Pollen-Specific Aquaporins NIP4;1 and NIP4;2 Are Required for Pollen Development and Pollination in Arabidopsis thaliana. THE PLANT CELL 2016; 28:1053-77. [PMID: 27095837 PMCID: PMC4904668 DOI: 10.1105/tpc.15.00776] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 03/22/2016] [Accepted: 04/14/2016] [Indexed: 05/18/2023]
Abstract
In flowers with dry stigmas, pollen development, pollination, and pollen tube growth require spatial and temporal regulation of water and nutrient transport. To better understand the molecular mechanisms involved in reproductive processes, we characterized NIP4;1 and NIP4;2, two pollen-specific aquaporins of Arabidopsis thaliana. NIP4;1 and NIP4;2 are paralogs found exclusively in the angiosperm lineage. Although they have 84% amino acid identity, they displayed different expression patterns. NIP4;1 has low expression levels in mature pollen, while NIP4;2 expression peaks during pollen tube growth. Additionally, NIP4;1pro:GUS flowers showed GUS activity in mature pollen and pollen tubes, whereas NIP4;2pro:GUS flowers only in pollen tubes. Single T-DNA mutants and double artificial microRNA knockdowns had fewer seeds per silique and reduced pollen germination and pollen tube length. Transport assays in oocytes showed NIP4;1 and NIP4;2 function as water and nonionic channels. We also found that NIP4;1 and NIP4;2 C termini are phosphorylated by a pollen-specific CPK that modifies their water permeability. Survival assays in yeast indicated that NIP4;1 also transports ammonia, urea, boric acid, and H2O2 Thus, we propose that aquaporins NIP4;1 and NIP4;2 are exclusive components of the reproductive apparatus of angiosperms with partially redundant roles in pollen development and pollination.
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Affiliation(s)
- Juliana Andrea Pérez Di Giorgio
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Dr. Héctor Torres (INGEBI-CONICET), C1428ADN Buenos Aires, Argentina
| | - Gerd Patrick Bienert
- Metalloid Transport Group, Department of Physiology and Cell Biology, Leibniz Institute of Plant Genetics and Crop Plant Research, D-06466 Gatersleben, Germany
| | - Nicolás Daniel Ayub
- Instituto de Genética Ewald A. Favret (CICVyA-INTA), Castelar, CC25 (1712) Buenos Aires, Argentina Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), C1033AAJ Buenos Aires, Argentina
| | - Agustín Yaneff
- Instituto de Biodiversidad y Biología Experimental y Aplicada (IBBEA-CONICET-UBA), Intendente Güiraldes 2160, Ciudad Universitaria, Pabellón II, C1428EGA Buenos Aires, Argentina Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Pabellón II, C1428EGA Buenos Aires, Argentina
| | - María Laura Barberini
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Dr. Héctor Torres (INGEBI-CONICET), C1428ADN Buenos Aires, Argentina
| | - Martín Alejandro Mecchia
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Dr. Héctor Torres (INGEBI-CONICET), C1428ADN Buenos Aires, Argentina
| | - Gabriela Amodeo
- Instituto de Biodiversidad y Biología Experimental y Aplicada (IBBEA-CONICET-UBA), Intendente Güiraldes 2160, Ciudad Universitaria, Pabellón II, C1428EGA Buenos Aires, Argentina Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Pabellón II, C1428EGA Buenos Aires, Argentina
| | - Gabriela Cynthia Soto
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Dr. Héctor Torres (INGEBI-CONICET), C1428ADN Buenos Aires, Argentina Instituto de Genética Ewald A. Favret (CICVyA-INTA), Castelar, CC25 (1712) Buenos Aires, Argentina Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), C1033AAJ Buenos Aires, Argentina
| | - Jorge Prometeo Muschietti
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Dr. Héctor Torres (INGEBI-CONICET), C1428ADN Buenos Aires, Argentina Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Pabellón II, C1428EGA Buenos Aires, Argentina
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10
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Deokar AA, Tar'an B. Genome-Wide Analysis of the Aquaporin Gene Family in Chickpea ( Cicer arietinum L.). FRONTIERS IN PLANT SCIENCE 2016; 7:1802. [PMID: 27965700 PMCID: PMC5126082 DOI: 10.3389/fpls.2016.01802] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 11/15/2016] [Indexed: 05/18/2023]
Abstract
Aquaporins (AQPs) are essential membrane proteins that play critical role in the transport of water and many other solutes across cell membranes. In this study, a comprehensive genome-wide analysis identified 40 AQP genes in chickpea (Cicer arietinum L.). A complete overview of the chickpea AQP (CaAQP) gene family is presented, including their chromosomal locations, gene structure, phylogeny, gene duplication, conserved functional motifs, gene expression, and conserved promoter motifs. To understand AQP's evolution, a comparative analysis of chickpea AQPs with AQP orthologs from soybean, Medicago, common bean, and Arabidopsis was performed. The chickpea AQP genes were found on all of the chickpea chromosomes, except chromosome 7, with a maximum of six genes on chromosome 6, and a minimum of one gene on chromosome 5. Gene duplication analysis indicated that the expansion of chickpea AQP gene family might have been due to segmental and tandem duplications. CaAQPs were grouped into four subfamilies including 15 NOD26-like intrinsic proteins (NIPs), 13 tonoplast intrinsic proteins (TIPs), eight plasma membrane intrinsic proteins (PIPs), and four small basic intrinsic proteins (SIPs) based on sequence similarities and phylogenetic position. Gene structure analysis revealed a highly conserved exon-intron pattern within CaAQP subfamilies supporting the CaAQP family classification. Functional prediction based on conserved Ar/R selectivity filters, Froger's residues, and specificity-determining positions suggested wide differences in substrate specificity among the subfamilies of CaAQPs. Expression analysis of the AQP genes indicated that some of the genes are tissue-specific, whereas few other AQP genes showed differential expression in response to biotic and abiotic stresses. Promoter profiling of CaAQP genes for conserved cis-acting regulatory elements revealed enrichment of cis-elements involved in circadian control, light response, defense and stress responsiveness reflecting their varying pattern of gene expression and potential involvement in biotic and abiotic stress responses. The current study presents the first detailed genome-wide analysis of the AQP gene family in chickpea and provides valuable information for further functional analysis to infer the role of AQP in the adaptation of chickpea in diverse environmental conditions.
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Lipchinsky A. Osmophoresis—a possible mechanism for vesicle trafficking in tip-growing cells. Phys Biol 2015; 12:066012. [DOI: 10.1088/1478-3975/12/6/066012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Maurel C, Boursiac Y, Luu DT, Santoni V, Shahzad Z, Verdoucq L. Aquaporins in Plants. Physiol Rev 2015; 95:1321-58. [DOI: 10.1152/physrev.00008.2015] [Citation(s) in RCA: 486] [Impact Index Per Article: 54.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Aquaporins are membrane channels that facilitate the transport of water and small neutral molecules across biological membranes of most living organisms. In plants, aquaporins occur as multiple isoforms reflecting a high diversity of cellular localizations, transport selectivity, and regulation properties. Plant aquaporins are localized in the plasma membrane, endoplasmic reticulum, vacuoles, plastids and, in some species, in membrane compartments interacting with symbiotic organisms. Plant aquaporins can transport various physiological substrates in addition to water. Of particular relevance for plants is the transport of dissolved gases such as carbon dioxide and ammonia or metalloids such as boron and silicon. Structure-function studies are developed to address the molecular and cellular mechanisms of plant aquaporin gating and subcellular trafficking. Phosphorylation plays a central role in these two processes. These mechanisms allow aquaporin regulation in response to signaling intermediates such as cytosolic pH and calcium, and reactive oxygen species. Combined genetic and physiological approaches are now integrating this knowledge, showing that aquaporins play key roles in hydraulic regulation in roots and leaves, during drought but also in response to stimuli as diverse as flooding, nutrient availability, temperature, or light. A general hydraulic control of plant tissue expansion by aquaporins is emerging, and their role in key developmental processes (seed germination, emergence of lateral roots) has been established. Plants with genetically altered aquaporin functions are now tested for their ability to improve plant tolerance to stresses. In conclusion, research on aquaporins delineates ever expanding fields in plant integrative biology thereby establishing their crucial role in plants.
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Affiliation(s)
- Christophe Maurel
- Biochimie et Physiologie Moléculaire des Plantes, Unité Mixte de Recherche 5004, CNRS/INRA/Montpellier SupAgro/Université de Montpellier, Montpellier, France
| | - Yann Boursiac
- Biochimie et Physiologie Moléculaire des Plantes, Unité Mixte de Recherche 5004, CNRS/INRA/Montpellier SupAgro/Université de Montpellier, Montpellier, France
| | - Doan-Trung Luu
- Biochimie et Physiologie Moléculaire des Plantes, Unité Mixte de Recherche 5004, CNRS/INRA/Montpellier SupAgro/Université de Montpellier, Montpellier, France
| | - Véronique Santoni
- Biochimie et Physiologie Moléculaire des Plantes, Unité Mixte de Recherche 5004, CNRS/INRA/Montpellier SupAgro/Université de Montpellier, Montpellier, France
| | - Zaigham Shahzad
- Biochimie et Physiologie Moléculaire des Plantes, Unité Mixte de Recherche 5004, CNRS/INRA/Montpellier SupAgro/Université de Montpellier, Montpellier, France
| | - Lionel Verdoucq
- Biochimie et Physiologie Moléculaire des Plantes, Unité Mixte de Recherche 5004, CNRS/INRA/Montpellier SupAgro/Université de Montpellier, Montpellier, France
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Safiarian MJ, Pertl-Obermeyer H, Lughofer P, Hude R, Bertl A, Obermeyer G. Lost in traffic? The K(+) channel of lily pollen, LilKT1, is detected at the endomembranes inside yeast cells, tobacco leaves, and lily pollen. FRONTIERS IN PLANT SCIENCE 2015; 6:47. [PMID: 25713578 PMCID: PMC4322604 DOI: 10.3389/fpls.2015.00047] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 01/16/2015] [Indexed: 05/26/2023]
Abstract
Fertilization in plants relies on fast growth of pollen tubes through the style tissue toward the ovules. This polarized growth depends on influx of ions and water to increase the tube's volume. K(+) inward rectifying channels were detected in many pollen species, with one identified in Arabidopsis. Here, an Arabidopsis AKT1-like channel (LilKT1) was identified from Lilium longiflorum pollen. Complementation of K(+) uptake deficient yeast mutants was only successful when the entire LilKT1 C-terminus was replaced by the AKT1 C-terminus. No signals were observed in the plasma membrane (PM) of pollen tubes after expression of fluorescence-tagged LilKT1 nor were any LilKT1-derived peptides detectable in the pollen PM by mass spectrometry analysis. In contrast, fluorescent LilKT1 partly co-localized with the lily PM H(+) ATPase LilHA2 in the PM of tobacco leaf cells, but exhibited a punctual fluorescence pattern and also sub-plasma membrane localization. Thus, incorporation of LilKT1 into the pollen PM seems tighter controlled than in other cells with still unknown trafficking signals in LilKT1's C-terminus, resulting in channel densities below detection limits. This highly controlled incorporation might have physiological reasons: an uncontrolled number of K(+) inward channels in the pollen PM will give an increased water influx due to the raising cytosolic K(+) concentration, and finally, causing the tube to burst.
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Affiliation(s)
- Minou J. Safiarian
- Molecular Plant Biophysics and Biochemistry, Department of Molecular Biology, University of SalzburgSalzburg, Austria
| | - Heidi Pertl-Obermeyer
- Molecular Plant Biophysics and Biochemistry, Department of Molecular Biology, University of SalzburgSalzburg, Austria
- Plant Systems Biology, University of HohenheimStuttgart, Germany
| | - Peter Lughofer
- Molecular Plant Biophysics and Biochemistry, Department of Molecular Biology, University of SalzburgSalzburg, Austria
| | - Rene Hude
- Molecular Plant Biophysics and Biochemistry, Department of Molecular Biology, University of SalzburgSalzburg, Austria
| | - Adam Bertl
- Yeast Membrane Biology, Department of Biology, Darmstadt University of TechnologyDarmstadt, Germany
| | - Gerhard Obermeyer
- Molecular Plant Biophysics and Biochemistry, Department of Molecular Biology, University of SalzburgSalzburg, Austria
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Shachar-Hill B, Hill AE, Powell J, Skepper JN, Shachar-Hill Y. Mercury-sensitive water channels as possible sensors of water potentials in pollen. JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:5195-205. [PMID: 24098048 PMCID: PMC3830494 DOI: 10.1093/jxb/ert311] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The growing pollen tube is central to plant reproduction and is a long-standing model for cellular tip growth in biology. Rapid osmotically driven growth is maintained under variable conditions, which requires osmosensing and regulation. This study explores the mechanism of water entry and the potential role of osmosensory regulation in maintaining pollen growth. The osmotic permeability of the plasmalemma of Lilium pollen tubes was measured from plasmolysis rates to be 1.32±0.31×10(-3) cm s(-1). Mercuric ions reduce this permeability by 65%. Simulations using an osmotic model of pollen tube growth predict that an osmosensor at the cell membrane controls pectin deposition at the cell tip; inhibiting the sensor is predicted to cause tip bursting due to cell wall thinning. It was found that adding mercury to growing pollen tubes caused such a bursting of the tips. The model indicates that lowering the osmotic permeability per se does not lead to bursting but rather to thickening of the tip. The time course of induced bursting showed no time lag and was independent of mercury concentration, compatible with a surface site of action. The submaximal bursting response to intermediate mercuric ion concentration was independent of the concentration of calcium ions, showing that bursting is not due to a competitive inhibition of calcium binding or entry. Bursting with the same time course was also shown by cells growing on potassium-free media, indicating that potassium channels (implicated in mechanosensing) are not involved in the bursting response. The possible involvement of mercury-sensitive water channels as osmosensors and current knowledge of these in pollen cells are discussed.
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Affiliation(s)
| | - Adrian E. Hill
- Department of Physiology, Development and Neuroscience, Cambridge University, Cambridge, UK
- * To whom correspondence should be addressed. E-mail:
| | - Janet Powell
- Multi-Imaging Centre, Cambridge University, Cambridge, UK
| | | | - Yair Shachar-Hill
- Department of Plant Biology, Plant Biology Building, Michigan State University, East Lansing, MI 48824-1312, USA
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Wu XN, Sanchez Rodriguez C, Pertl-Obermeyer H, Obermeyer G, Schulze WX. Sucrose-induced receptor kinase SIRK1 regulates a plasma membrane aquaporin in Arabidopsis. Mol Cell Proteomics 2013; 12:2856-73. [PMID: 23820729 PMCID: PMC3790296 DOI: 10.1074/mcp.m113.029579] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2013] [Revised: 06/30/2013] [Indexed: 11/06/2022] Open
Abstract
The transmembrane receptor kinase family is the largest protein kinase family in Arabidopsis, and it contains the highest fraction of proteins with yet uncharacterized functions. Here, we present functions of SIRK1, a receptor kinase that was previously identified with rapid transient phosphorylation after sucrose resupply to sucrose-starved seedlings. SIRK1 was found to be an active kinase with increasing activity in the presence of an external sucrose supply. In sirk1 T-DNA insertional mutants, the sucrose-induced phosphorylation patterns of several membrane proteins were strongly reduced; in particular, pore-gating phosphorylation sites in aquaporins were affected. SIRK1-GFP fusions were found to directly interact with aquaporins in affinity pull-down experiments on microsomal membrane vesicles. Furthermore, protoplast swelling assays of sirk1 mutants and SIRK1-GFP expressing lines confirmed a direct functional interaction of receptor kinase SIRK1 and aquaporins as substrates for phosphorylation. A lack of SIRK1 expression resulted in the failure of mutant protoplasts to control water channel activity upon changes in external sucrose concentrations. We propose that SIRK1 is involved in the regulation of sucrose-specific osmotic responses through direct interaction with and activation of an aquaporin via phosphorylation and that the duration of this response is controlled by phosphorylation-dependent receptor internalization.
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Affiliation(s)
- Xu Na Wu
- Max Planck Institute for Molecular Plant Physiology, Am Mühlenberg 1, 14476 Golm, Germany
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Hepler PK, Rounds CM, Winship LJ. Control of cell wall extensibility during pollen tube growth. MOLECULAR PLANT 2013; 6:998-1017. [PMID: 23770837 PMCID: PMC4043104 DOI: 10.1093/mp/sst103] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
In this review, we address the question of how the tip-growing pollen tube achieves its rapid rate of elongation while maintaining an intact cell wall. Although turgor is essential for growth to occur, the local expansion rate is controlled by local changes in the viscosity of the apical wall. We focus on several different structures and underlying processes that are thought to be major participants including exocytosis, the organization and activity of the actin cytoskeleton, calcium and proton physiology, and cellular energetics. We think that the actin cytoskeleton, in particular the apical cortical actin fringe, directs the flow of vesicles to the apical domain, where they fuse with the plasma membrane and contribute their contents to the expanding cell wall. While pH gradients, as generated by a proton-ATPase located on the plasma membrane along the side of the clear zone, may regulate rapid actin turnover and new polymerization in the fringe, the tip-focused calcium gradient biases secretion towards the polar axis. The recent data showing that exocytosis of new wall material precedes and predicts the process of cell elongation provide support for the idea that the intussusception of newly secreted pectin contributes to decreases in apical wall viscosity and to cell expansion. Other prime factors will be the localization and activity of the enzyme pectin methyl-esterase, and the chelation of calcium by pectic acids. Finally, we acknowledge a role for reactive oxygen species in the control of wall viscosity.
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Affiliation(s)
- Peter K Hepler
- Biology Department, University of Massachusetts, Amherst, MA 01003, USA.
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Firon N, Nepi M, Pacini E. Water status and associated processes mark critical stages in pollen development and functioning. ANNALS OF BOTANY 2012; 109:1201-14. [PMID: 22523424 PMCID: PMC3359924 DOI: 10.1093/aob/mcs070] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Accepted: 02/24/2012] [Indexed: 05/18/2023]
Abstract
BACKGROUND The male gametophyte developmental programme can be divided into five phases which differ in relation to the environment and pollen hydration state: (1) pollen develops inside the anther immersed in locular fluid, which conveys substances from the mother plant--the microsporogenesis phase; (2) locular fluid disappears by reabsorption and/or evaporation before the anther opens and the maturing pollen grains undergo dehydration--the dehydration phase; (3) the anther opens and pollen may be dispersed immediately, or be held by, for example, pollenkitt (as occurs in almost all entomophilous species) for later dispersion--the presentation phase; (4) pollen is dispersed by different agents, remaining exposed to the environment for different periods--the dispersal phase; and (5) pollen lands on a stigma and, in the case of a compatible stigma and suitable conditions, undergoes rehydration and starts germination--the pollen-stigma interaction phase. SCOPE This review highlights the issue of pollen water status and indicates the various mechanisms used by pollen grains during their five developmental phases to adjust to changes in water content and maintain internal stability. CONCLUSIONS Pollen water status is co-ordinated through structural, physiological and molecular mechanisms. The structural components participating in regulation of the pollen water level, during both dehydration and rehydration, include the exine (the outer wall of the pollen grain) and the vacuole. Recent data suggest the involvement of water channels in pollen water transport and the existence of several molecular mechanisms for pollen osmoregulation and to protect cellular components (proteins and membranes) under water stress. It is suggested that pollen grains will use these mechanisms, which have a developmental role, to cope with environmental stress conditions.
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Affiliation(s)
- Nurit Firon
- Institute of Plant Sciences, The Volcani Center, ARO, Bet Dagan, Israel.
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Hill AE, Shachar-Hill B, Skepper JN, Powell J, Shachar-Hill Y. An osmotic model of the growing pollen tube. PLoS One 2012; 7:e36585. [PMID: 22615784 PMCID: PMC3353927 DOI: 10.1371/journal.pone.0036585] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Accepted: 04/10/2012] [Indexed: 11/19/2022] Open
Abstract
Pollen tube growth is central to the sexual reproduction of plants and is a longstanding model for cellular tip growth. For rapid tip growth, cell wall deposition and hardening must balance the rate of osmotic water uptake, and this involves the control of turgor pressure. Pressure contributes directly to both the driving force for water entry and tip expansion causing thinning of wall material. Understanding tip growth requires an analysis of the coordination of these processes and their regulation. Here we develop a quantitative physiological model which includes water entry by osmosis, the incorporation of cell wall material and the spreading of that material as a film at the tip. Parameters of the model have been determined from the literature and from measurements, by light, confocal and electron microscopy, together with results from experiments made on dye entry and plasmolysis in Lilium longiflorum. The model yields values of variables such as osmotic and turgor pressure, growth rates and wall thickness. The model and its predictive capacity were tested by comparing programmed simulations with experimental observations following perturbations of the growth medium. The model explains the role of turgor pressure and its observed constancy during oscillations; the stability of wall thickness under different conditions, without which the cell would burst; and some surprising properties such as the need for restricting osmotic permeability to a constant area near the tip, which was experimentally confirmed. To achieve both constancy of pressure and wall thickness under the range of conditions observed in steady-state growth the model reveals the need for a sensor that detects the driving potential for water entry and controls the deposition rate of wall material at the tip.
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Affiliation(s)
- Adrian E Hill
- Department of Physiology, Cambridge University, Cambridge, United Kingdom.
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Li X, Wang X, Yang Y, Li R, He Q, Fang X, Luu DT, Maurel C, Lin J. Single-molecule analysis of PIP2;1 dynamics and partitioning reveals multiple modes of Arabidopsis plasma membrane aquaporin regulation. THE PLANT CELL 2011; 23:3780-97. [PMID: 22010034 PMCID: PMC3229149 DOI: 10.1105/tpc.111.091454] [Citation(s) in RCA: 191] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2011] [Revised: 09/09/2011] [Accepted: 10/03/2011] [Indexed: 05/17/2023]
Abstract
PIP2;1 is an integral membrane protein that facilitates water transport across plasma membranes. To address the dynamics of Arabidopsis thaliana PIP2;1 at the single-molecule level as well as their role in PIP2;1 regulation, we tracked green fluorescent protein-PIP2;1 molecules by variable-angle evanescent wave microscopy and fluorescence correlation spectroscopy (FCS). Single-particle tracking analysis revealed that PIP2;1 presented four diffusion modes with large dispersion of diffusion coefficients, suggesting that partitioning and dynamics of PIP2;1 are heterogeneous and, more importantly, that PIP2;1 can move into or out of membrane microdomains. In response to salt stress, the diffusion coefficients and percentage of restricted diffusion increased, implying that PIP2;1 internalization was enhanced. This was further supported by the decrease in PIP2;1 density on plasma membranes by FCS. We additionally demonstrated that PIP2;1 internalization involves a combination of two pathways: a tyrphostin A23-sensitive clathrin-dependent pathway and a methyl-β-cyclodextrin-sensitive, membrane raft-associated pathway. The latter was efficiently stimulated under NaCl conditions. Taken together, our findings demonstrate that PIP2;1 molecules are heterogeneously distributed on the plasma membrane and that clathrin and membrane raft pathways cooperate to mediate the subcellular trafficking of PIP2;1, suggesting that the dynamic partitioning and recycling pathways might be involved in the multiple modes of regulating water permeability.
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Affiliation(s)
- Xiaojuan Li
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- Graduate University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaohua Wang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- Graduate University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yong Yang
- Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Key Laboratory of Molecular Nanostructures and Nanotechnology, Chinese Academy of Sciences, Beijing 100190, China
| | - Ruili Li
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- Graduate University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qihua He
- Peking University Health Science Center, Beijing 100191, China
| | - Xiaohong Fang
- Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Key Laboratory of Molecular Nanostructures and Nanotechnology, Chinese Academy of Sciences, Beijing 100190, China
| | - Doan-Trung Luu
- Biochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes, Unité Mixte de Recherche 5004 Centre National de la Recherche Scientifique/Unité Mixte de Recherche 0386 Institut National de la Recherche Agronomique/Montpellier SupAgro/Université Montpellier 2, F-34060 Montpellier Cedex 2, France
| | - Christophe Maurel
- Biochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes, Unité Mixte de Recherche 5004 Centre National de la Recherche Scientifique/Unité Mixte de Recherche 0386 Institut National de la Recherche Agronomique/Montpellier SupAgro/Université Montpellier 2, F-34060 Montpellier Cedex 2, France
| | - Jinxing Lin
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
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Winship LJ, Obermeyer G, Geitmann A, Hepler PK. Pollen tubes and the physical world. TRENDS IN PLANT SCIENCE 2011; 16:353-5. [PMID: 21536475 DOI: 10.1016/j.tplants.2011.03.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2010] [Revised: 10/26/2010] [Accepted: 03/11/2011] [Indexed: 05/10/2023]
Abstract
The primary goal of our previous opinion paper (Winship, L.J. et al. (2010) Trends Plant Sci. 15, 363-369) [1] was to put two models for the control of pollen tube growth on the same theoretical and biophysical footing, and to then test both for consistency with basic principles and with experimental data. Our central thesis, then and now, is that the biophysical and biochemical mechanisms that enable pollen tubes to grow and to respond to their environment evolved in a physical context constrained by known, inescapable principles. First, pressure is a scalar, not a vector quantity. Second, the water movement in and out of plant cells that generates pressure is passive, not active, and is controlled by differences in water potential. Here we respond to the issues raised by Zonia and Munnik (Trends Plant Sci. 2011; this issue) [2] in the light of new evidence concerning turgor pressure and pollen tube growth rates.
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Vera-Estrella R, Bohnert HJ. Physiological Roles for the PIP Family of Plant Aquaporins. THE PLANT PLASMA MEMBRANE 2011. [DOI: 10.1007/978-3-642-13431-9_8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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Hachez C, Chaumont F. Aquaporins: a family of highly regulated multifunctional channels. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 679:1-17. [PMID: 20666220 DOI: 10.1007/978-1-4419-6315-4_1] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Aquaporins (AQPs) were discovered as channels facilitatingwater movement across cellular membranes. Whereas much of the research has focused on characterizing AQPs with respect to cell water homeostasis, recent discoveries in terms of the transport selectivity of AQP homologs has shed new light on their physiological roles. In fact, whereas some AQPs behave as "strict" water channels, others can conduct a wide range ofnonpolar solutes, such as urea or glycerol and even more unconventional permeants, such as the nonpolar gases carbon dioxide and nitric oxide, the polar gas ammonia, the reactive oxygen species hydrogen peroxide and the metalloids antimonite, arsenite, boron and silicon. This suggests that AQPs are also key players in various physiological processes not related to water homeostasis. The function, regulation and biological importance of AQPs in the different kingdoms is reviewed in this chapter, with special emphasis on animal and plant AQPs.
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Affiliation(s)
- Charles Hachez
- Institut des Sciences de la Vie, Universit4 catholique de Louvain, Croix du Sud 5-15, B-1348 Louvain-la-Neuve, Belgium
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Winship LJ, Obermeyer G, Geitmann A, Hepler PK. Under pressure, cell walls set the pace. TRENDS IN PLANT SCIENCE 2010; 15:363-9. [PMID: 20483654 PMCID: PMC2999822 DOI: 10.1016/j.tplants.2010.04.005] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2010] [Revised: 04/16/2010] [Accepted: 04/21/2010] [Indexed: 05/18/2023]
Abstract
Significant controversy still swirls around the regulation of extension by tip-growing cells, particularly during stable, oscillatory growth of pollen tubes. One explanation proposes that turgor pressure is both the controlling and driving force. We refute this hypothesis on theoretical and evidentiary grounds. Direct measurement of intracellular pressure reveals constant turgor even as growth rates change. Measured ion fluxes, notably potassium, are insufficient to account for the requisite osmotic changes. Water movement, and hence pressure gradients, occur throughout the cell, unrestricted to local domains. Increases in hydrostatic pressure alone would force water out of the cell rather than cause increased growth. We have recently demonstrated concomitant changes in the apical cell wall that account fully for observed changes in growth rate.
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Coimbra S, Costa M, Mendes MA, Pereira AM, Pinto J, Pereira LG. Early germination of Arabidopsis pollen in a double null mutant for the arabinogalactan protein genes AGP6 and AGP11. ACTA ACUST UNITED AC 2010; 23:199-205. [PMID: 20162305 DOI: 10.1007/s00497-010-0136-x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2009] [Accepted: 02/01/2010] [Indexed: 12/25/2022]
Abstract
The pollen specificity of the Arabidopsis arabinogalactan protein (AGP) genes AGP6 and AGP11 suggests that they are integral to pollen biogenesis, and their high percent of sequence similarity may indicate a potential for overlapping function. Arabidopsis agp6 agp11 double null mutants have been studied in our laboratory, and in the present work, we characterize the germination and growth of its pollen. When compared to wild type, mutant agp6 agp11 pollen displayed reduced germination and elongation, both in vivo and in vitro, and precocious germination inside the anthers, provided that sufficient moisture was available. This characteristic was not observed in wild type plants, even in water content conditions which for the mutant were sufficient for pollen germination. Therefore, an additional distinctive phenotypic trait of arabinogalactan proteins AGP6 and AGP11 may be to avert untimely germination of pollen. Such AGPs may control germination through water uptake, suggesting an important biological function of this gene family in pollen.
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Affiliation(s)
- Sílvia Coimbra
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Edifício FC4 Rua do Campo Alegre s/n, 4169-007, Porto, Portugal.
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Zonia L, Munnik T. Uncovering hidden treasures in pollen tube growth mechanics. TRENDS IN PLANT SCIENCE 2009; 14:318-27. [PMID: 19446491 DOI: 10.1016/j.tplants.2009.03.008] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2008] [Revised: 02/22/2009] [Accepted: 03/03/2009] [Indexed: 05/08/2023]
Abstract
The long-standing model of tip growth in pollen tubes considers that exocytosis and growth occur at the apex and that the pool of very small vesicles in the apical dome contains secretory (exocytic) vesicles. However, recent work on vesicle trafficking dynamics in tobacco pollen tubes shows that exocytosis occurs in the subapical region. Taking these and other new results into account, we set out to resolve specific problems that are endemic in current models and present a two-part ACE (apical cap extension)-H (hydrodynamics) growth model. The ACE model involves delivery and recycling of materials required for new cell synthesis and the H model involves mechanisms that integrate and regulate key cellular pathways and drive cell elongation during growth.
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Affiliation(s)
- Laura Zonia
- Swammerdam Institute for Life Sciences, Plant Physiology Section, University of Amsterdam, Kruislaan 904, 1098 XH Amsterdam, The Netherlands.
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Vandeleur RK, Mayo G, Shelden MC, Gilliham M, Kaiser BN, Tyerman SD. The role of plasma membrane intrinsic protein aquaporins in water transport through roots: diurnal and drought stress responses reveal different strategies between isohydric and anisohydric cultivars of grapevine. PLANT PHYSIOLOGY 2009; 149:445-60. [PMID: 18987216 PMCID: PMC2613730 DOI: 10.1104/pp.108.128645] [Citation(s) in RCA: 244] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2008] [Accepted: 10/31/2008] [Indexed: 05/18/2023]
Abstract
We report physiological and anatomical characteristics of water transport across roots grown in soil of two cultivars of grapevine (Vitis vinifera) differing in response to water stress (Grenache, isohydric; Chardonnay, anisohydric). Both cultivars have similar root hydraulic conductances (Lo; normalized to root dry weight) that change diurnally. There is a positive correlation between Lo and transpiration. Under water stress, both cultivars have reduced minimum daily Lo (predawn) attributed to the development of apoplastic barriers. Water-stressed and well-watered Chardonnay had the same diurnal change in amplitude of Lo, while water-stressed Grenache showed a reduction in daily amplitude compared with well-watered plants. Hydraulic conductivity of root cortex cells (Lpcell) doubles in Chardonnay but remains unchanged in Grenache. Of the two most highly expressed plasma membrane intrinsic protein (PIP) aquaporins in roots (VvPIP1;1 and VvPIP2;2), only VvPIP2;2 functions as a water channel in Xenopus laevis oocytes. VvPIP1;1 interacts with VvPIP2;2 to induce 3-fold higher water permeability. These two aquaporins are colocated in the root from in situ hybridization and immunolocalization of VvPIP1 and VvPIP2 subfamily members. They occur in root tip, exodermis, root cortex (detected up to 30 mm), and stele. VvPIP2;2 mRNA does not change diurnally or with water stress, in contrast to VvPIP1;1, in which expression reflects the differences in Lo and Lpcell between cultivars in their responses to water stress and rewatering. VvPIP1;1 may regulate water transport across roots such that transpirational demand is matched by root water transport capacity. This occurs on a diurnal basis and in response to water stress that corresponds to the difference in drought tolerance between the cultivars.
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Affiliation(s)
- Rebecca K Vandeleur
- School of Agriculture, Food, and Wine, University of Adelaide, Waite Campus, Urrbrae, South Australia 5064, Australia
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