Overexpression of an actin Gh_D04G0865 gene in cotton reduced fineness of fiber

Abstract

AbstractCotton fibers are the world's most important renewable source of fiber for textile industry. The cell wall of cotton fiber determines fiber quality parameters for textile industry. The thickness of secondary cell wall and the fiber perimeter define the fineness and micronaire (MIC) of cotton fiber. The fineness of cotton fiber plays an important role in affecting the yarn quality. Actin cytoskeleton impacts the cell extension and shape, however how it affects secondary cell wall is unclear. We overexpressed the actin isovariant Gh_D04G0865 (previously shown mutation in this gene impaired fiber length) under fiber‐specific promoter in cotton. We obtained two independent transgenic lines. Fiber characteristics of their first‐generation progenies were evaluated by high volume instrument (HVI), advanced fiber information system (AFIS), Cottonscope, and Fourier‐transform infrared (FT‐IR) spectroscopy. Fiber of transgenic lines with excessive expression of actin showed significant reduction in MIC and fineness, while increase in strength. Seed index was increased in transgenic lines overexpressing actin. FT‐IR analysis detected changes in vibrations associated with crystalline cellulose. Taken together, our findings revealed that actin cytoskeleton may play roles in reducing fiber wall thickening process during secondary cell wall biosynthesis.