Genome-wide analysis of the NAC gene family and functional verification of the DcNAC043s in Dendrobium catenatum

Abstract

The NAC (NAM, ATAF1/2 and CUC2) domain protein plays an important role in plant growth and development. The function of members of NAC gene family has been deeply studied in many plants. However, the evolutionary relationships and characteristics of NAC family genes in Dendrobium catenatum (D. candidum) unclear. In this study, we identified 33 NAC genes in D.catenatum, all contain NAM conservative domain. Subcellular localization predictions indicated that all the DcNAC proteins are localized to the nucleus. Phylogenetic analysis suggested that the DcNAC gene family could be divided into four groups. Then, the amino-acid composition, physicochemical properties, gene structure, motif, and promoter cis-acting elements were analyzed, the evolutionarily conservative gene DcNAC043-1 and DcNAC043-2 were found. Using qRT-PCR and phloroglucinol staining experiments, it was demonstrated that DcNAC043s can respond to drought stress in Dendrobium. Within a certain range, the longer the duration of drought stress, the higher the expression level of DcNAC043s, and the stronger the degree of plant lignification. We supplemented the relevant information of NAC gene family in D. catenatum. At the same time, the gene function of DcNAC043s and its contribution to the response of Dendrobium to drought stress were verified. These results provide a comprehensive evolutionary history of NAC genes in D. catenatum, and insight into the biological functions of DcNAC043s genes in response to drought stress.