Working group session:
Functional Genomics
Presentation type:
oral
Authors:
Gong, Siying; Li, Xuebao
Presenter:
Li, Xuebao
Correspondent:
Li, Xuebao
Abstract:
Cotton (Gossypium hirsutum L.) is the most important textile fiber crop in the world. Cotton fiber, a highly elongated and thickened single cell derived from the ovule epidermis, provides an excellent system for study on cell elongation and secondary cell wall biosynthesis. In this study, a gene, GhKNL1 (KNOTTED1-LIKE), encoding a classical Class II KNOX protein was identified in cotton. GhKNL1 was preferentially expressed in developing fibers at the stage of secondary cell wall (SCW) biosynthesis. GhKNL1 protein is localized in cell nucleus, and could interact with GhOFP4, as well as AtOFP1, AtOFP4 and AtMYB75. However, GhKNL1 protein lacks the activity of transcriptional activation. Dominant repression of GhKNL1 gene affected fiber development of cotton. The expression levels of the genes related to fiber elongation and SCW biosynthesis were altered in the transgenic fibers of cotton. As a result, the transgenic cotton plants produced the aberrant, shrunken and collapsed fiber cells. Length and cell wall thickness of fibers of the transgenic cotton plants were significantly reduced, compared with those of wild type. Furthermore, overexpression and dominant repression of GhKNL1 in Arabidopsis resulted in a reduction in interfascicular fiber cell wall thickening of basal stems of transgenic plants. Complementation test revealed that GhKNL1 rescued the defective phenotype of Arabidopsis knat7 mutant in some extent. Given the data together, it is suggested that GhKNL1 participates in regulation of fiber development via modulating expression of the genes related to cell elongation and secondary wall biosynthesis of cotton fibers. Additionally, our study also provides the candidate intrinsic gene for improving fiber quality by genetic manipulation.