Yang, Liu, Ge et al. explore the relationship between brassinosteroids and very-long-chain fatty acids in regulating fiber elongation.
By Zuoren Y, Zhao L, Xiaoyang G, Lili L, Wenqiang Q, Qanmber G, Le L, Zhi W, and Fuguang L
Zhengzhou Research Base, State Key Laboratory of Cotton Biology, School of Agricultural Sciences, Zhengzhou University, Zhengzhou, Henan, China;
State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, Henan, China
Western Agricultural Research Center, Chinese Academy of Agricultural Sciences, Changji, Xinjiang, China
Background: Cotton (Gossypium hirsutum) produces natural fibers for textile production. Cotton fibers are single-celled epidermal seed trichomes that are excellent models to study plant cell development. In recent years, brassinosteroid (BR) plant hormones and very-long-chain fatty acids (VLCFAs) have been reported to promote fiber elongation. However, the molecular mechanism by which BRs and VLCFAs regulate fiber elongation remains largely unknown. Therefore, we explored the mechanisms and relationship between BRs and VLCFAs in regulating fiber elongation.
Question: How do BRs regulate fiber cell elongation? What is the relationship between BRs and VLCFAs in regulating fiber elongation?
Findings: BR deficiency reduced the expression of 3-ketoacyl-CoA synthase genes (GhKCSs), which encode the rate-limiting enzymes involving in VLCFA biosynthesis, leading to lower saturated VLCFAs contents. In vitro cultured ovules showed that BR acts upstream of VLCFAs. GhBES1.4, a master transcription factors of BR signaling, increased VLCFA contents and fiber elongation. DNA binding assays revealed that GhBES1.4 directly binds to the promoter of GhKCS10_At to induce its expression, thereby promoting fiber elongation. GhKCS10_At regulated the biosynthesis of endogenous VLCFAs and acts as a positive regulator of fiber development. These results indicated that BRs regulate cotton fiber elongation by modulating VLCFA biosynthesis.
Next steps: Since BRs regulate fiber elongation through modulating VLCFA biosynthesis, how VLCFAs work as signal molecule in regulating fiber development is a fascinating question for future research.
Zuoren Yang, Zhao Liu, Xiaoyang Ge, Lili Lu, Wenqiang Qin, Ghulam Qanmber, Le Liu, Zhi Wang, and Fuguang Li. (2023). Brassinosteroids regulate cotton fiber elongation by modulating very-long-chain fatty acid biosynthesis. https://doi.org/10.1093/plcell/koad060