GhDET2, a Steroid 5α-Reductase, Plays an Important Role in Cotton Fiber Cell Initiation and Elongation.

The study investigated the role of GhDET2, a steroid 5α-reductase, in cotton fiber development. GhDET2 was cloned from cotton fiber cells and confirmed to encode a functional enzyme. High GhDET2 transcript levels were observed during fiber initiation and elongation stages. Suppressing GhDET2 expression or using finasteride, a 5α-reductase inhibitor, inhibited fiber growth, but this effect was reversed by epibrassinolide, a brassinosteroid. Seed coat-specific expression of GhDET2 increased fiber number and length. The findings indicated that GhDET2 and brassinosteroids were crucial for cotton fiber cell initiation and elongation, suggesting potential for improving fiber quality or yield through modulation of brassinosteroid biosynthesis.