ZmWRKY74 participates in maize drought stress response through regulating antioxidant enzyme activity and proline...

Maize (Zea mays L.) is a profoundly important food crop and industrial raw material. However, the increasing frequency of drought events in recent years poses a serious threat to its production. Unravelling the molecular mechanisms underlying drought stress responses in maize is essential for improving yield. In this study, a drought-tolerant mutant was screened and identified, and functional analysis was conducted on a key mutated gene, ZmWRKY74. The results demonstrated that overexpression of ZmWRKY74 significantly reduced drought tolerance in maize. The overexpression lines exhibited decreased antioxidant enzyme activities and proline content, along with increased sensitivity to drought-induced oxidative damage. Further investigation revealed that ZmWRKY74 interacts with ZmNAC49. This interaction not only suppressed the expression of ZmSOD3 but also enhanced the binding affinity of ZmWRKY74 to the ZmAAP3 promoter, thereby strengthening the transcriptional repression of ZmAAP3. The results of this findings indicate that the ZmWRKY74 plays a crucial role in the drought stress response by regulating antioxidant enzyme activity and proline accumulation. This research untangles a novel regulatory mechanism of ZmWRKY74 under drought conditions, providing a theoretical foundation and potential molecular target for improving crop drought tolerance through genetic engineering approaches.