Genome-Wide Identification and Analysis of the NAC Transcription Factor Gene Family in Garden Asparagus ()

As a large plant-specific gene family, the NAC (NAM, ATAF1/2, and CUC2) transcription factor is related to plant growth, development, and response to abiotic stresses. Although the draft genome of garden asparagus () has been released, the genome-wide investigation of the NAC gene family is still unavailable. In this study, a total of 85 genes were identified, and a comprehensive analysis of the gene family was performed, including physicochemical properties, phylogenetic relationship, chromosome localization, gene structure, conserved motifs, intron/exon, cis-acting elements, gene duplication, syntenic analysis, and differential gene expression analysis. The phylogenetic analysis demonstrated that there were 14 subgroups in both and , and the genes with a similar gene structure and motif distribution were clustered in the same group. The cis-acting regulatory analysis of genes indicated four types of cis-acting elements were present in the promoter regions, including light-responsive, hormone-responsive, plant-growth-and-development-related, and stress-responsive elements. The chromosomal localization analysis found that 81 genes in were unevenly distributed on nine chromosomes, and the gene duplication analysis showed three pairs of tandem duplicated genes and five pairs of segmental duplications, suggesting that gene duplication is possibly associated with the amplification of the NAC gene family. The differential gene expression analysis revealed one and three genes that were upregulated and downregulated under different types of salinity stress, respectively. This study provides insight into the evolution, diversity, and characterization of genes in garden asparagus and will be helpful for future understanding of their biological roles and molecular mechanisms in plants.