title: Silencing the vacuolar invertase gene GhVIN1 blocks cotton fiber initiation from the ovule epidermis, probably by suppressing a cohort of regulatory genes via sugar signaling.
abstract: Cotton fibers, the most important source of cellulose for the global textile industry, are single-celled trichomes derived from the ovule epidermis at or just prior to anthesis. Despite progress in understanding cotton fiber elongation and cell-wall biosynthesis, knowledge regarding the molecular basis of fiber cell initiation, the first step of fiber development determining the fiber yield potential, remains elusive. Here, we provide evidence that expression of a vacuolar invertase (VIN) is an early event that is essential for cotton fiber initiation. RNAi-mediated suppression of GhVIN1, a major VIN gene that is highly expressed in wild-type fiber initials, resulted in significant reduction of VIN activity and consequently a fiberless seed phenotype in a dosage dependent manner. The absence of a negative effect on seed development in these fiberless seeds indicates that the phenotype is unlikely to be due to lack of carbon nutrient. Gene expression analyses coupled with in vitro ovule culture experiments revealed that GhVIN1-derived hexose signaling may play an indispensable role in cotton fiber initiation, probably by regulating the transcription of several MYB transcription factors and auxin signaling components that were previously identified as required for fiber initiation. Together, the data represent a significant advance in understanding the mechanisms of cotton fiber initiation, and provide the first indication that VIN-mediated hexose signaling may act as an early event modulating the expression of regulatory genes and hence cell differentiation from the ovule epidermis.
authors.affiliation: School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW, 2308, Australia; Australia-China Research Centre for Crop Improvement, University of Newcastle, Callaghan, NSW, 2308, Australia.
authors.forename: Lu
authors.initials: L
authors.lastname: Wang
authors.forename: Akiko
authors.initials: A
authors.lastname: Cook
authors.forename: John W
authors.initials: JW
authors.lastname: Patrick
authors.forename: Xiao-Ya
authors.initials: XY
authors.lastname: Chen
authors.forename: Yong-Ling
authors.initials: YL
authors.lastname: Ruan
mesh_terms: D001483:Base Sequence; D032561:Cotton Fiber; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D006601:Hexoses / Q000378:metabolism / Q000494:pharmacology; D007210:Indoleacetic Acids / Q000378:metabolism / Q000494:pharmacology; D008855:Microscopy, Electron, Scanning; D056771:Ovule / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D019441:Plant Epidermis / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D010937:Plant Growth Regulators / Q000378:metabolism / Q000494:pharmacology; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified; D020598:Proto-Oncogene Proteins c-myb / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012639:Seeds / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D012689:Sequence Homology, Nucleic Acid; D015398:Signal Transduction; D046509:Tissue Culture Techniques; D014617:Vacuoles / Q000201:enzymology; D043324:beta-Fructofuranosidase / Q000235:genetics* / Q000378:metabolism
chemical_list: D006601:Hexoses; D007210:Indoleacetic Acids; D010937:Plant Growth Regulators; D010940:Plant Proteins; D020598:Proto-Oncogene Proteins c-myb; D043324:beta-Fructofuranosidase
keywords: MYB; auxin signaling; cell differentiation; fiber initiation; sugar signaling; vacuolar invertase