Roles of NAC transcription factors in cotton

Climate deterioration, water shortages, and abiotic stress are the main threats worldwide that seriously affect cotton growth, yield, and fiber quality. Therefore, research on improving cotton yield and tolerance to biotic and abiotic stresses is of great importance. The NAC proteins are crucial and plant-specific transcription factors(TFs) that are involved in cotton growth, development, and stress responses. The comprehensive utilization of cotton NAC TFs in the improvement of cotton varieties through novel biotechnological methods is feasible. Based on cotton genomic data, genome-wide identification and analyses have revealed potential functions of cotton NAC genes. Here, we comprehensively summarize the recent progress in understanding cotton NAC TFs roles in regulating responses to drought, salt, and Verticillium wilt-related stresses, as well as leaf senescence and the development of fibers, xylem, and glands. The detailed regulatory network of NAC proteins in cotton is also elucidated. Cotton NAC TFs directly bind to the promoters of genes associated with ABA biosynthesis and secondary cell-wall formation, participate in several biological processes by interacting with related proteins, and regulate the expression of downstream genes. Studies have shown that the overexpression of NAC TF genes in cotton and other model plants improve their drought or salt tolerance. This review elucidates the latest findings on the functions and regulation of cotton NAC proteins, broadens our understanding of cotton NAC TFs, and lays a fundamental foundation for further molecular breeding research in cotton.