Systematical characterization of YUCCA gene family in five cotton species, and potential functions of YUCCA22 gene in drought resistance of cotton

Abstract

Auxin plays an essential role in the normal growth and development of plants. The tryptophan aminotransferase of Arabidopsis (TAA)/YUCCA (YUC) enzymes functions as flavin monooxygenases (FMOs), which are the key enzymes in auxin synthesis. However, comprehensive characterization of the YUC gene family in cotton has not yet been completed. In order to reveal the functions of YUC genes in cotton, we systematically identified and characterized the YUC gene family in five species of cotton including analysis of the member, characterization, intragenomic duplication, and collinear relationships. Transcriptomic analysis indicates that GhYUCs participate in abiotic stress processes in cotton. The GhYUC22 gene that is responsive to polyethylene glycol (PEG) and abscisic acid (ABA) was functionally identified via virus-induced gene silencing (VIGS). Subsequent natural drought simulation experiments and physiological index data demonstrated that partial silencing of GhYUC22 gene endowed cotton with drought resistance by modulating indole-3-acetic acid (IAA) and ABA signaling pathways. In conclusion, our findings support the role of that GhYUC22 gene in modulating both endogenous auxin and ABA homeostasis and regulating the drought resistance in cotton.