Temporal expression profiling of GhNAC transcription factor genes in cotton cultivars under abiotic stresses

Gossypium sp. is a significant natural fiber source for the textile industry around the world. The crop yield is unfavorably affected as a result of various stress factors. The plant-specific NAC (NAM, ATAF and CUC) proteins form a major transcription factor (TF) family prominent for their roles in diverse developmental processes. We examined cotton NAC TF within the plant TF database, wherein we found 18 distinctive phylogenetically segregated subfamilies comprising 78 NAC domain-containing proteins. Here, we report previously uncharacterized cotton NAC transcription factors which are diversified structurally. Six upland cotton cultivars were selected for the study and a quantitative RT-PCR shown the expressions of 17 GhNAC genes in leaves and roots which were regulated in cold, heat, salt and drought stresses. In cold stress, the expression profile of GhNAC2 showed more than 100-log fold increase in all the cultivars studied and subsequent analysis revealed that GhNAC9 was found to be highly expressed during the heat stress among all the cultivars. GhNAC15 expression during salinity recorded more than 100-log fold increase in all the cultivars except KC-3. Genes GhNAC2, GhNAC9, and GhNAC11 were found to be upregulated during drought stress induced by mannitol and dehydration. These results confirmed that reputed functions of several GhNAC TFs, which in turn will contribute towards for their functional characterization and applications for genetic and agricultural cotton crop improvement.