A gain-of-function allele of a DREB transcription factor gene ameliorates drought tolerance in wheat
Fangming Mei, Bin Chen, Linying Du, Shumin Li, Dehe Zhu, Nan Chen, Yifang Zhang, Fangfang Li, Zhongxue Wang, Xinxiu Cheng, Li Ding, Zhensheng Kang and Hude Mao
Plant Cell
https://doi.org/10.1093/plcell/koac248
Abstract
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-B-Del574, which exhibits stronger transcriptional activation, protein interactions, and binding activity to dehydration-responsive elements (DRE)/CRT cis-elements than the TaDTG6-B-In574 encoded by the allele lacking the deletion, thus conferring greater drought tolerance in wheat seedlings harboring this variant. Knockdown of TaDTG6-B-Del574 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-B-Del574 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-B-Del574. Further analysis showed that TaDTG6-B-Del574 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. GWAS identifies a gain-of-function allele of TaDTG6-B, which directly activates TaPIF1 transcription by binding to DRE/CRT cis-elements and ameliorates drought tolerance.