title: Cotton (Gossypium hirsutum) 14-3-3 proteins participate in regulation of fibre initiation and elongation by modulating brassinosteroid signalling.
abstract: Cotton (Gossypium hirsutum) fibre is an important natural raw material for textile industry in the world. Understanding the molecular mechanism of fibre development is important for the development of future cotton varieties with superior fibre quality. In this study, overexpression of Gh14-3-3L in cotton promoted fibre elongation, leading to an increase in mature fibre length. In contrast, suppression of expression of Gh14-3-3L, Gh14-3-3e and Gh14-3-3h in cotton slowed down fibre initiation and elongation. As a result, the mature fibres of the Gh14-3-3 RNAi transgenic plants were significantly shorter than those of wild type. This 'short fibre' phenotype of the 14-3-3 RNAi cotton could be partially rescued by application of 2,4-epibrassinolide (BL). Expression levels of the BR-related and fibre-related genes were altered in the Gh14-3-3 transgenic fibres. Furthermore, we identified Gh14-3-3 interacting proteins (including GhBZR1) in cotton. Site mutation assay revealed that Ser163 in GhBZR1 and Lys51/56/53 in Gh14-3-3L/e/h were required for Gh14-3-3-GhBZR1 interaction. Nuclear localization of GhBZR1 protein was induced by BR, and phosphorylation of GhBZR1 by GhBIN2 kinase was helpful for its binding to Gh14-3-3 proteins. Additionally, 14-3-3-regulated GhBZR1 protein may directly bind to GhXTH1 and GhEXP promoters to regulate gene expression for responding rapid fibre elongation. These results suggested that Gh14-3-3 proteins may be involved in regulating fibre initiation and elongation through their interacting with GhBZR1 to modulate BR signalling. Thus, our study provides the candidate intrinsic genes for improving fibre yield and quality by genetic manipulation.
authors.affiliation: Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhou
authors.forename: Ze-Ting
authors.initials: ZT
authors.lastname: Zhang
authors.forename: Mo
authors.initials: M
authors.lastname: Li
authors.forename: Xin-Zheng
authors.initials: XZ
authors.lastname: Wei
authors.forename: Xiao-Jie
authors.initials: XJ
authors.lastname: Li
authors.forename: Bing-Ying
authors.initials: BY
authors.lastname: Li
authors.forename: Xue-Bao
authors.initials: XB
authors.lastname: Li
mesh_terms: D048948:14-3-3 Proteins / Q000378:metabolism*; D001483:Base Sequence; D060406:Brassinosteroids / Q000378:metabolism* / Q000494:pharmacology; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D032561:Cotton Fiber; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D003368:Gossypium / Q000187:drug effects / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D008239:Lysine / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D010940:Plant Proteins / Q000378:metabolism*; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding / Q000187:drug effects; D021381:Protein Transport / Q000187:drug effects; D060888:Real-Time Polymerase Chain Reaction; D012694:Serine / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013260:Steroids, Heterocyclic / Q000494:pharmacology
chemical_list: D048948:14-3-3 Proteins; D060406:Brassinosteroids; D010940:Plant Proteins; D013260:Steroids, Heterocyclic; D012694:Serine; D008239:Lysine; C023623:brassinolide
keywords: 14-3-3 protein; brassinosteroid (BR) signalling; cotton (Gossypium hirsutum); fibre development; protein-protein interaction; regulation of gene expression