Function analysis of ZmZHD9, a positive regulator in drought stress response in transgenic maize

Abstract Backgrounds: Drought stress is one of the major factors that affects maize yield. ZF-HD transcription factors have been proved to play pivotal roles in the regulation of plant growth, hormone conduction signaling and abiotic stress response. However, the molecular mechanism of ZmZHD9-mediated drought tolerance is not well understood. Results: In the present study, we analyzed the functions of ZmZHD9, a member of the maize ZF-HD family. ZmZHD9 is predominantly expressed in leaves, and was induced by drought, salinity, high temperature and abscisic acid (ABA). Subcellular localization indicated that ZmZHD9 protein was localized in the nucleus. ZmZHD9-overexpressing plants showed increased tolerance to drought stress compared with wild-type plants, evaluated by higher RWC and proline content, higher SOD and POD activity, lower REL and MDA content in transgenic plants under drought stress. In addition, the expression of six stress-responsive genes were significantly higher in ZmZHD9 transgenic plants than that in wild-type plants under drought stress.Conclusion: These results demonstrate that ZmZHD9 as a stress-responsive transcription factor which plays a positive regulatory role in response to drought.