GhMYB25-like: a key factor in early cotton fibre development

Plant J. 2011 Mar;65(5):785-97. doi: 10.1111/j.1365-313X.2010.04464.x. Epub 2011 Jan 14.

Abstract

MYB transcription factors have been implicated in regulation of the development of ovule epidermal cells into the elongated seed fibres of cotton. An R2R3 MYB, GhMYB25-like, identified from its reduced expression in a fibreless mutant of cotton (Xu142 fl), is here shown to play a key role in the very early stages of fibre cell differentiation. A GhMYB25-like promoter-GUS construct was expressed predominantly in the epidermal layers of cotton ovules before anthesis (-3days post-anthesis, dpa), increasing in expression in 0-dpa ovules, primarily in those epidermal cells expanding into fibres, and then in elongating fibres at +3dpa, declining thereafter. This was consistent with GhMYB25-like transcript abundance during fibre development. RNA interference suppression of GhMYB25-like resulted in cotton plants with fibreless seeds, but normal trichomes elsewhere, phenocopying the Xu142 fl mutant. Like Xu142 fl these plants had reduced expression of the fibre-expressed MYBs, GhMYB25 and GhMYB109, indicating that GhMYB25-like is upstream from those MYBs. This hierarchy was supported by the absence of any change in transcript level of GhMYB25-like in GhMYB25- and GhMYB109-silenced transgenic lines. Transgenic cotton with an additional copy of the native gene had elevated expression of GhMYB25-like in ovules, but no obvious increase in fibre initials, suggesting that there may be other factors that interact with GhMYB25-like to differentiate epidermal cells into fibre cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Cloning, Molecular
  • Cotton Fiber
  • DNA, Plant / genetics
  • Gene Expression Regulation, Developmental
  • Gene Expression Regulation, Plant
  • Gossypium / genetics*
  • Gossypium / metabolism
  • Microscopy, Electron, Scanning
  • Molecular Sequence Data
  • Ovule / genetics
  • Ovule / metabolism
  • Ovule / ultrastructure
  • Plant Epidermis / genetics
  • Plant Epidermis / metabolism
  • Plant Proteins / genetics
  • Plant Proteins / metabolism*
  • Plants, Genetically Modified / genetics
  • Plants, Genetically Modified / metabolism
  • Promoter Regions, Genetic
  • RNA Interference
  • Sequence Alignment
  • Sequence Analysis, DNA
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*

Substances

  • DNA, Plant
  • Plant Proteins
  • Transcription Factors