Plant & Animal Genomes XIII Conference

January 15-19, 2005
Town & Country Convention Center
San Diego, CA

Cotton Fiber Development: Transcriptome Analysis And Characterization Of A Myb Transcription Factor

Xiao-Ya Chen , Shui Wang , Jin-Ying Gou , Jia-Wei Wang , Nan Yu , Chun-Hong Li

  National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, SIBS, CAS, Shanghai 200032, China

Cotton fibers and Arabidopsis trichomes are single-celled epidermal hairs and they provide an ideal system for studying cell fate determination and cell growth. We have generated 7,800 cotton ESTs and selected 5,100 non-repeated clones to make the cotton cDNA arrays. We conducted SAGE analysis of the fiber and ovule transcriptome. Over 200,000 tags were analyzed representing more than 50,000 unique tags. We found that promoter of a cotton fiber gene, RDL1, directs trichome-specific expression when transferred into Arabidopsis plants. By dissecting the promoter we identified two transcription factors that regulate the trichome-expression, they are a GL1-like MYB protein GaFIF1 and a GL-2 like homeobox protein GaHOX3, respectively. GL1::FIF1 rescued trichome formation of a gl1 mutant. Further analysis showed that the intronless cDNAs of GL1-like MYB genes (FIF1, GL1 and WER) failed to function in controlling trichome production, and the intron (intron1) is required to prevent ectopic expression of the MYB gene. In Arabidopsis expressing of the FIF1 cDNA up-regulated such negative regulators as TRY, but the intron-containing gene did not. In cotton, FIF1 gene is expressed early in developing fiber cells. It interesting to note that Arabidopsis plants expressing 35S::FIF1 produced seed-hairs. These data strongly suggest that FIF1 plays a key role in regulating cotton fiber development.