* Address correspondence to Lichao Zhang (zhanglichao@caas.cn), Xiuying Kong (kongxiuying@caas.cn) and Xu Liu (liuxu03@caas.cn)

† These authors contributed equally to this work

Heading date affects yield and adaptability in wheat (Triticum aestivum L.). Characterizing the genes that regulate heading date would provide insight into the molecular mechanisms underlying heading date regulation and thereby facilitate efforts to breed high-yielding wheat varieties. We previously identified a heading regulatory gene in wheat, TaMYB72, and established its role in promoting flowering through heterologous expression analysis in rice.

In this study, we further demonstrated the role of TaMYB72 in regulating heading date and yield traits in wheat. TaMYB72, a MYB-related transcription factor, was shown to transactivate transcription in yeast. Compared with wild-type plants, the heading and maturation dates of TaMYB72 knockout mutants were delayed by about 11 and 6 days, respectively.

Moreover, the mutants exhibited increased plant height, spike length, grain number per spike, grain length, and grain weight—all traits associated with increased yield. Furthermore, an electrophoretic mobility shift assay, dual-luciferase reporter, yeast one-hybrid, and chromatin immunoprecipitation-qPCR assays suggested that TaMYB72 directly activates expression of the heading date gene TaFT and thereby promotes heading and enhances grain yield traits in wheat.

Together, our results indicate that TaMYB72 is an important factor in the regulation of wheat grain yield and that mutants harboring defects in this gene can be used as germplasm resources for wheat improvement.