GbEXPATR, a species-specific expansin, enhances cotton fibre elongation through cell wall restructuring

Yang Li, Lili Tu, Filomena A. Pettolino, Shengmei Ji, Juan Hao, Daojun Yuan, Fenglin Deng, Jiafu Tan, Haiyan Hu, Qing Wang, Danny J. Llewellyn, Xianlong Zhang

Research output: Contribution to journalArticlepeer-review

80 Citations (Scopus)


Cotton provides us the most important natural fibre. High fibre quality is the major goal of cotton breeding, and introducing genes conferring longer, finer and stronger fibre from Gossypium barbadense to Gossypium hirsutum is an important breeding strategy. We previously analysed the G. barbadense fibre development mechanism by gene expression profiling and found two homoeologous fibre-specific α-expansins from G. barbadense, GbEXPA2 and GbEXPATR. GbEXPA2 (from the DT genome) is a classical α-expansin, while its homoeolog, GbEXPATR (AT genome), encodes a truncated protein lacking the normal C-terminal polysaccharide-binding domain of other α-expansins and is specifically expressed in G. barbadense. Silencing EXPA in G. hirsutum induced shorter fibres with thicker cell walls. GbEXPA2 overexpression in G. hirsutum had no effect on mature fibre length, but produced fibres with a slightly thicker wall and increased crystalline cellulose content. Interestingly, GbEXPATR overexpression resulted in longer, finer and stronger fibres coupled with significantly thinner cell walls. The longer and thinner fibre was associated with lower expression of a number of secondary wall-associated genes, especially chitinase-like genes, and walls with lower cellulose levels but higher noncellulosic polysaccharides which advocated that a delay in the transition to secondary wall synthesis might be responsible for better fibre. In conclusion, we propose that α-expansins play a critical role in fibre development by loosening the cell wall; furthermore, a truncated form, GbEXPATR, has a more dramatic effect through reorganizing secondary wall synthesis and metabolism and should be a candidate gene for developing G. hirsutum cultivars with superior fibre quality.

Original languageEnglish
Pages (from-to)951-963
Number of pages13
JournalPlant Biotechnology Journal
Issue number3
Publication statusPublished - Mar 1 2016


  • Cell elongation
  • Cotton fibre
  • Gossypium barbadense (cotton)
  • Secondary cell wall
  • Truncated α-expansin

ASJC Scopus subject areas

  • Biotechnology
  • Agronomy and Crop Science
  • Plant Science


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