Genome-wide analysis of the rose (Rosa chinensis) NAC family and characterization of RcNAC091.

KEY MESSAGE: A genome-wide analysis identified 116 NAC genes in rose, including stress-related ones with different expression patterns under drought and salt stress. Silencing of RcNAC091, a member of the ATAF subfamily, decreased dehydration tolerance in rose. The NAC (NAM, ATAF, and CUC) transcription factors (TFs) are plant-specific proteins that regulate various developmental processes and stress responses. However, knowledge of the NAC TFs in rose (Rosa chinensis), one of the most important horticultural crops, is limited. In this study, 116 NAC genes were identified from the rose genome and classified into 16 subfamilies based on protein phylogenetic analysis. Chromosomal mapping revealed that the RcNAC genes were unevenly distributed on the seven chromosomes of rose. Gene structure and motif analysis identified a total of ten conserved motifs, of which motifs 1-7 were highly conserved and present in most rose NACs, while motifs 8-10 were present only in a few subfamilies. Further study of the stress-related RcNACs based on the transcriptome data showed differences in the expression patterns among the organs, at various floral developmental stages, and under drought and salt stress in rose leaves and roots. The stress-related RcNACs possessed cis-regulatory elements (CREs) categorized into three groups corresponding to plant growth and development, phytohormone response, and abiotic and biotic stress response. Reverse transcription-quantitative real-time PCR (RT-qPCR) analysis of 11 representative RcNACs revealed their differential expression in rose leaves and roots under abscisic acid (ABA), polyethylene glycol (PEG), and sodium chloride (NaCl) treatments. Furthermore, the silencing of RcNAC091 verified its role in positively regulating the dehydration stress response. Overall, the present study provides valuable insights into stress-related RcNACs and paves the way for stress tolerance in rose.