Identification and expression analysis of the NAC transcription factor family in durum wheat ( Triticum turgidum L. ssp. durum )

The NAC (NAM, ATAF and CUC) proteins belong to one of the largest plant-specific transcription factor (TF) families and play important roles in plant development processes, response to biotic and abiotic cues and hormone signaling. Our analysis led to the identification of 168 NAC genes in durum wheat, including nine putative membrane-bound TFs and 48 homeologous genes pairs. Phylogenetic analyses of TtNACs along with their Arabidopsis, grape, barley and rice counterparts divided these proteins into 8 phylogenetic groups and allowed the identification of TtNAC-A7, TtNAC-B35, TtNAC-A68, TtNAC-B69 and TtNAC-A43 as homologs of OsNAC1, OsNAC8, OsNTL2, OsNTL5 and ANAC025/NTL14, respectively. In silico expression analysis, using RNA-seq data, revealed tissue-specific and stress responsive TtNAC genes. The expression of ten selected genes was analyzed under salt and drought stresses in two contrasting tolerance cultivars. This analysis is the first report of NAC gene family in durum wheat and will be useful for the identification and selection of candidate genes associated with stress tolerance.