A gain-of-function allele of a DREB transcription factor gene ameliorates drought tolerance in wheat

• Published in: The Plant cell 2022-10, Vol.34 (11), p.4472-4494
• Main Authors: Mei, Fangming, Chen, Bin, Du, Linying, Li, Shumin, Zhu, Dehe, Chen, Nan, Zhang, Yifang, Li, Fangfang, Wang, Zhongxue, Cheng, Xinxiu, Ding, Li, Kang, Zhensheng, Mao, Hude
• Format: Article
• Language: English
• Subjects: Alleles; Droughts; Gain of Function Mutation; Gene Expression Regulation, Plant - genetics; Genome-Wide Association Study; Plant Breeding; Plant Proteins - genetics; Plant Proteins - metabolism; Plants, Genetically Modified - genetics; Stress, Physiological - genetics; Transcription Factors - genetics; Transcription Factors - metabolism; Triticum - metabolism
• ISSN: 1040-4651; 1532-298X
• DOI: 10.1093/plcell/koac248

Drought is a major environmental factor limiting wheat production worldwide. However, the genetic components underlying wheat drought tolerance are largely unknown. Here, we identify a DREB transcription factor gene (TaDTG6-B) by genome-wide association study that is tightly associated with drought tolerance in wheat. Candidate gene association analysis revealed that a 26-bp deletion in the TaDTG6-B coding region induces a gain-of-function for TaDTG6-BDel574, which exhibits stronger transcriptional activation, protein interactions, and binding activity to dehydration-responsive elements (DRE)/CRT cis-elements than the TaDTG6-BIn574 encoded by the allele lacking the deletion, thus conferring greater drought tolerance in wheat seedlings harboring this variant. Knockdown of TaDTG6-BDel574 transcripts attenuated drought tolerance in transgenic wheat, whereas its overexpression resulted in enhanced drought tolerance without accompanying phenotypic abnormalities. Furthermore, the introgression of the TaDTG6-BDel574 elite allele into drought-sensitive cultivars improved their drought tolerance, thus providing a valuable genetic resource for wheat breeding. We also identified 268 putative target genes that are directly bound and transcriptionally regulated by TaDTG6-BDel574. Further analysis showed that TaDTG6-BDel574 positively regulates TaPIF1 transcription to enhance wheat drought tolerance. These results describe the genetic basis and accompanying mechanism driving phenotypic variation in wheat drought tolerance, and provide a novel genetic resource for crop breeding programs.