Abstract: 【Objective】This study was designed to identify the NAC gene family in Rosa chinensis ‘Old Blush’, analyze the sequences characteristics and expression pattern of RcNACs to reveal the biological functions of RcNACs. It also provides an important foundation to explore the role of RcNACs in prickles. 【Method】The BLATP and HMMER search were conducted to identify NAC proteins in Rosa chinensis ‘Old Blush’ using the sequences of NAC proteins of Arabidopsis. Physical and chemical properties, subcellular location, structure and phylogenetic relationship of each gene were further analyzed. Based on the released transcriptome data, the expression characteristics of RcNACs in different tissues and organs and under different stress conditions were analyzed. What’s more, the technology of RNA-seq was used to screen RcNAC genes that might be related to the prickle development. 【Result】In this study, we identified and characterized 116 NAC genes from Rosa chinensis ‘Old Blush’ genome. These RcNACs genes encoded proteins containing 69 to 713 amino acids, with the theoretical isoelectric points ranging from 4.43 to 9.54 and the molecular weight ranging from 7.87 to 79.99kD. The prediction of subcellular localization showed that 81 RcNACs were located in the nucleus. Moreover, RcNACs were unevenly distributed on 7 chromosomes. According to phylogenetic relationships, AtNACs, OsNACs and RcNACs were clustered into 21 groups. These 116 RcNACs were differentially expressed in various tissues and organs, and the expression levels of 31 members changed in response to abiotic and biotic stresses. Furthermore, in the RNA-seq data of prickles, 53 RcNACs were detected, of which 26 members were differentially expressed genes. 【Conclusion】This study demonstrated that RcNACs were involved in the regulation of plant development and stress responses. Some members might be involved in the processes of prickle cell proliferation, secondary cell wall biosynthesis and programmed cell death, which could be selected as candidate genes related with prickle development for further study.

Key words: Rosa chinensis , ‘Old Blush’, NAC transcription factor,  , transcriptome sequencing,  , prickle development