JA signaling through ZmZIM12 protein to determine nitrogen use efficiency via regulation of nitrate uptake in maize

JA signaling through ZmZIM12 protein to regulate nitrate uptake, and overexpression of ZmZIM12 protein can improve nitrogen use efficiency in maize. Abstract Nitrogen (N) is an essential nutrient for maize growth and development, and related to maize grain yield. Jasmonic acid (JA) plays an essential role in regulating stress-response and plant growth. However, the regulatory mechanism about JA signaling to regulate nitrate uptake for improving NUE (nitrogen use efficiency) in maize remains elusive. Here, we report that exogenous JA have double effective on absorption nitrate in maize, which low content of JA promotes nitrate uptake, by contrast, high content of JA inhibits nitrate uptake. Jas-ZIM-domain transcriptional repressor 12 (ZmZIM12) acts as an upstreaming transcriptional-repression factor in JA signaling. JA signaling through ZmZIM12 to control root growth and regulate the expression of ZmNRTs for modulating nitrate uptake. In hydroponic, overexpression of ZmZIM12 proteins can promote root growth and increase the expression of ZmNRTs for absorption of nitrate. In two-year field trials, ZmZIM12OE lines has bigger dry matter, higher NUE and more grain yield than WT. Therefore, our data reshape a regulatory mechanism of JA signaling through ZmZIM12 protein to regulate ZmNRTs gene’s expression for mediating nitrate uptake, and provide guidance for improving maize NUE in maize breeding.