Genome wide analysis of NAC gene family 'sequences' in sugarcane and its comparative phylogenetic relationship with rice, sorghum, maize and Arabidopsis for prediction of stress associated NAC genes

A total of 85 NAC genes of sugarcane (ScNAC) were retrieved from GRASSIUS (grass regulatory information server). An overview of this gene family is presented including conserved domains, phylogenies, comparative analysis of NAC genes of sugarcane with its closest relative sorghum and with other monocot species. Among the Poaceae family, the NAC genes from sugarcane showed high sequence identity with most of the NAC genes of Sorghum bicolor. A highly conserved two proline residues, a glycine, phenyl alanine and leucine residues are present in N-terminal domain. Conserved amino acid residues and phylogeny helps us to classify the ScNAC gene family into two major groups (Group I and II) and five subgroups (A-E). The analysis of phylogenetic tree of NAC protein sequences of sugarcane with sorghum, rice, maize and Arabidopsis reveals distinct clades with several orthologs and paralogs. A total of 30 pairs of paralogous NAC genes were identified in sugarcane. Based on the orthology, putative stress associated NAC genes were predicted in sugarcane. These stress associated NAC genes of sugarcane and their orthologs from other species were clustered in the phylogenetic tree and shared common motifs, revealing the possibility of functional similarities within this subgroup.