Genome-wide analysis and expression patterns of the NAC transcription factor family in Medicago truncatula.

NAC transcription factor (TF) family proteins are expressed in various developmental stages and following various stresses. NAC TFs are involved in mediating various physiological functions of plants and participate in various signaling pathways under biotic or abiotic stress. The present study provided a comprehensive functional analysis of members of the MtNAC TF family. Via screening of Medicago truncatula genome information, we identified 97 MtNAC TFs in M. truncatula and compared the phylogenetic analysis of 14 conserved groups with their Arabidopsis and rice counterparts. The NAC TFs were categorized into 14 groups based on their conserved motifs and gene structure. The predicted M. truncatula NAC genes were distributed among eight chromosomes, and in addition, we found that these genes showed mass gene duplication. Through expression profiling of RNA-seq data analysis, we determined that NAC family members were expressed significantly under different abiotic stresses. This indicates that the NAC TF shows different functions in M. truncatula. Together, this genome-wide analysis of the NAC gene family in M. truncatula, could be applied to improving stress tolerance in plants.