Comprehensive analysis of the NAC gene family in Elaeis guineensis

The NAC gene family encode transcriptional regulator that contain a conserved NAM domain near the N-terminus and participate in the regulation of plant development and response to different abiotic stresses. In this study, 129 EgNAC genes were identified from the genome sequence of Elaeis guineensis and 97 EgNAC located on the chromsomes with an average of 4.56 EgNAC genes per chromosome. About 60% of EgNACs contained three exons and the gene sizes varied from 541 bp to 37,294 bp. Genomic duplication analysis showed that 10 EgNAC genes were involved in segmental duplication events and two genes were from tandem duplication. The gene expression profiles of EgNACs based on transcriptome database for different oil palm tissues showed that 30 EgNACs with low or no expression and 24 EgNACs were specifically expressed in one tissue. The trancriptome comparison between the control and cold stress samples demonstrated that thirty-seven EgNACs were down-regulated and 82 EgNACs were up-regulated under cold stress. Further RT-qPCR showed that the expression for 24 out of 32 validated EgNACs were induced under both cold, drought and salt stresses. Our comprehensive analysis of EgNAC genes has provided clues for candidate genes involved in abiotic stress tolerance.