Promotes Fiber Cell Elongation and Cell Wall Thickness by Increasing PI and IP Accumulation in Cotton.

The omega-3 fatty acid desaturase enzyme gene is responsible for converting linoleic acid to linolenic acid in plant fatty acid synthesis. Despite limited knowledge of its role in cotton growth, our study focused on , a gene within the family, which was found to promote fiber elongation and cell wall thickness in cotton. was predominantly expressed in elongating fibers, and its suppression led to shorter fibers with reduced cell wall thickness and phosphoinositide (PI) and inositol triphosphate (IP) levels. Transcriptome analysis of knock-out mutants revealed significant impacts on genes involved in the phosphoinositol signaling pathway. Experimental evidence demonstrated that positively regulated the expression of the and genes, influencing cotton fiber development through the inositol signaling pathway. The application of PI and IP externally increased fiber length in knock-out plants, while inhibiting PI led to a reduced fiber length in overexpressing plants. These findings suggest that plays a crucial role in enhancing fiber development by promoting PI and IP biosynthesis, offering the potential for breeding cotton varieties with superior fiber quality.