Identification, classification and bioinformatics expression analysis of NAC transcription factor gene family in Hordeum vulgare cv. Morex genome

NAC gene family is one large family of plant-specific transcription factor that plays various roles in plant developmental stages and stress responses. The possibility of bioinformatics studies on NAC gene family in barley was provided with completion of the genome sequencing of Hordeum vulgare cv. Morex project. In this research using genome scanning, 73 non-redundant NAC-encoding genes in total were identified from the genomic sequences of Hordeum vulgare cv. Morex. A composite phylogenetic tree was constructed with HvNAC protein sequences and a number of known rice and Arabidopsis NAC protein sequences and tree was classified into 15 distinct subgroups. It is revealed the uneven distribution of the HvNAC genes on barley chromosomes. Most members of NAC genes were not located in groups (singletons) and few members of this family were located in groups with two or three genes. Most detected cis elements in upstream and downstream of HvNAC genes were involved in response to light, response to abiotic stresses and relatively low in response to biotic stresses. In silico gene expression analysis revealed that HvNAC genes were expressed in a wide range of tissues and is not highly expressed in developmental stages. Also, the HvNAC genes partly is expressed in stress conditions, especially in abiotic stresses and relatively less expressed in biotic stresses. This bioinformatics information provide a framework for genomics and functional studies of this gene family in barley.