Characterization and Functional Analysis of , A NAM Domain Gene, Coordinates the Leaf Senescence in Upland Cotton ( L.).

In the process of growth and development, cotton exhibits premature senescence under various abiotic stresses, impairing yield and fiber quality. NAC (NAM, ATAF1,2, and CUC2) protein widely distributed in land plants, play the critical role in responding to abiotic stress and regulating leaf senescence. We have identified and functional analyzed a NAM domain gene in upland cotton, it was located on the A11 chromosome 4,921,702 to 4,922,748 bp, only containing one exon. The spatio-temporal expression pattern analysis revealed that it was highly expressed in root, torus, ovule and fiber development stage. The results of qRT-PCR validated that negatively regulated by salt stress, drought stress, HO stress, IAA treatment, and ethylene treatment, positively regulated by the ABA and MeJA treatment. Moreover, heterologous overexpression of results in leaf premature senescence and delays root system development in . The phenotype of delayed-senescence was performed after silencing by VIGS in premature cotton. Taken together, was involved in different abiotic stress pathways and play important roles in negatively regulating leaf premature senescence.