https://www.mdpi.com/1422-0067/23/14/7581
International Journal of Molecular Sciences，23(14)，7581（2022）
Zhenru Guo 1,2,† , Qing Chen 2,†, Jing Zhu 2 , Yan Wang 2 , Yang Li 2 , Qingcheng Li 2 , Kan Zhao 2 , Yue Li 2 , Rui Tang 2 , Xiaoli Shi 2 , Kenan Tan 2 , Li Kong 2 , Yunfeng Jiang 2 , Qiantao Jiang 2 , Jirui Wang 2 , Guoyue Chen 2 , Yuming Wei 2 , Youliang Zheng 2,* and Pengfei Qi 2,*
Common wheat (Triticum aestivumL.) is an important food crop with a unique processing quality. TheQgene positively regulates the processing quality of wheat, but the underlying mechanism remains unclear. Here, a newQallele (Qc5) responsible for compact spikes and good bread performance was identified. Compared with theQallele widely distributed in modern common wheat cultivars,Qc5had a missense mutation outside the miRNA172-binding site. This missense mutation led to a more compact messenger RNA (mRNA) secondary structure around the miRNA172-binding region, resulting in increasedQc5expression during the spike development stage and a consequent increase in spike density. Furthermore, this missense mutation weakened the physical interaction between Qc5and storage protein activator (SPA) in seeds and suppressed the expression ofstorage protein repressor(SPR). These changes increased the grain protein content and improved the bread-making quality of wheat. In conclusion, a missense mutation increasesQexpression because of the resulting highly folded mRNA secondary structure around the miRNA172-binding site. Furthermore, this mutation improves the bread-making quality of wheat by repressing the expression ofSPRand influencing the physical interaction between Q and SPA. These findings provide new insights into the miRNA172-directed regulation of gene expression, with implications for wheat breeding.
