A new network containing MYB109-ZmCesA5 is involved in kernel development.

MYB genes regulate several different aspects of metabolism and development. However, few studies have reported the involvement of MYBs-CesAs network in the regulation of maize kernel development. In this study, yeast one-hybrid (Y1H) assays and dual-luciferase reporter assays showed that ZmMYB109 activated the expression of ZmCesA5 by directly binding to its promoter. Real-time quantitative PCR (RT-qPCR) and transcriptome analyses showed that ZmMYB109 expression increased in ZmCesA5-OE kernels and decreased in ZmCesA5-KO kernels. Overexpression of ZmCesA5 produced heavier kernels, whereas loss of function of ZmCesA5 affected starch and sucrose metabolism, resulting in weight reduction of the maize kernels. Collectively, these findings suggest that a new network containing MYB109-ZmCesA5 is involved in kernel development.