Variation in cis-regulation of a NAC transcription factor contributes to drought tolerance in wheat

• DOI: 10.1016/j.molp.2021.11.007
• Publication Date: 2021-11-15T07:02:09Z
• Authors: Hude Mao; Shumin Li; Bin Chen; Chao Jian; Fangming Mei; Yifang Zhang; Fangfang Li; Nan Chen; Tian Li; Linying Du; Li Ding; Zhongxue Wang; Xinxiu Cheng; Xiaojing Wang; Zhensheng Kang
• Keywords: Drought Tolerance; MYB; Introgression; Indel

Drought is a major environmental factor limiting wheat production worldwide, and developing drought-tolerant cultivars is a central challenge for wheat breeders globally. Therefore, it is important to identify genetic components determining drought tolerance in wheat. In this study, we identified a wheat NAC gene (TaNAC071-A) that is tightly associated with drought tolerance by a genome-wide association study. Knockdown of TaNAC071-A in wheat attenuated plant drought tolerance, whereas its overexpression significantly enhanced drought tolerance through improved water-use efficiency and increased expression of stress-responsive genes. This heightened water-saving mechanism mitigated the yield loss caused by water deficit. Further candidate gene association analysis showed that a 108-bp insertion in the promoter of TaNAC071-A alters its expression level and contributes to variation in drought tolerance among wheat accessions. This insertion contains two MYB cis-regulatory elements (CREs) that can be directly bound by the MYB transcription activator, TaMYBL1, thereby leading to increased TaNAC071-A expression and plant drought tolerance. Importantly, introgression of this 108-bp insertion allele, TaNAC071-AIn-693, into drought-sensitive cultivars could improve their drought tolerance, demonstrating that it is a valuable genetic resource for wheat breeding. Taken together, our findings highlight a major breakthrough in determining the genetic basis underlying phenotypic variation in wheat drought tolerance and showcase the potential of exploiting CRE-containing indels for improving important agronomical traits.