Isolation, Expression Analysis, and Function Evaluation of 12 Novel Stress‐Responsive Genes of NAC Transcription Factors in Sweetpotato

• Published in: Crop science 2018-05, Vol.58 (3), p.1328-1341
• Main Authors: Meng, Xiaoqing, Li, Ge, Yu, Jing, Cai, Jing, Dong, Tingting, Sun, Jian, Xu, Tao, Li, Zongyun, Pan, Shenyuan, Ma, Daifu, Zhu, Mingku
• Format: Article
• Language: English
• ISSN: 0011-183X; 1435-0653
• DOI: 10.2135/cropsci2017.12.0738

NAC (NAM, ATAF, and CUC) transcription factors function as the nodes of regulatory networks in response to various biotic and abiotic stresses. Although they have been widely studied in many species, no knowledge concerning salt‐stress‐responsive NAC genes is available in sweetpotato (Ipomoea batatas L.). In the present study, 12 novel putative NAC genes, designated as IbNAC1L and IbNAC3 through IbNAC13, were isolated on the basis of the salt‐stress‐treated RNA sequencing data of two sweetpotato cultivars (‘XuShu 22’ and ‘XuShu 32’) with different levels of salt tolerance. Motif compositions showed that all the IbNAC proteins except IbNAC9 contain five conserved subdomains in the NAC domain region that characterizes the NAC gene family. Furthermore, systematic expression analysis and function evaluation of these IbNAC genes were conducted using quantitative real‐time polymerase chain reaction. The results showed that the expression of most IbNAC genes was exclusively induced by multiple abiotic stresses, including NaCl, dehydration, cold, and heat. Varying degrees of induction were also observed in the transcription levels of these IbNACs, except IbNAC10, when treated with various hormones, including abscisic acid, 1‐aminocyclopropane‐1‐carboxylate, gibberellic acid, and jasmonic acid. Cumulatively, the data of stress‐responsive IbNAC genes in the present study will provide valuable information for further exploring the crucial and diverse roles of IbNAC genes in sweetpotato stress tolerance.