ZmWRKY83 Negatively Regulates Waterlogging Stress in Maize

Abstract

Waterlogging is a major abiotic stress that restricts maize growth and yield. WRKY transcription factors play important roles in plant stress responses; however, the functions of many maize WRKY members in waterlogging tolerance remain poorly understood. In this study, we investigated the role of ZmWRKY83 in maize responses to waterlogging. ZmWRKY83 expression was significantly downregulated in maize roots under waterlogging stress. Functional analysis showed that ZmWRKY83-overexpressing lines exhibited growth comparable to that of wild-type plants under normal conditions but more severe growth inhibition and lower shoot and root fresh weights after waterlogging treatment. Physiological analyses further revealed that ZmWRKY83 overexpression impaired adventitious root formation, increased membrane damage, and reduced antioxidant capacity under waterlogging conditions. Transcriptome analysis revealed that the differentially expressed genes were primarily enriched in plant hormone signal transduction, secondary metabolism, and phenylpropanoid biosynthesis. Further investigation identified the auxin-responsive gene ZmIAA7 as a potential downstream target of ZmWRKY83. qRT-PCR, DLR, and Y1H assays indicated that ZmWRKY83 directly binds to the ZmIAA7 promoter and represses its transcriptional activity. Collectively, these findings suggest that ZmWRKY83 negatively regulates maize waterlogging tolerance by suppressing auxin-related responses through ZmIAA7, expanding the regulatory network underlying WRKY-mediated responses to waterlogging in maize.