ZmWRKY107 modulates salt tolerance in maize plants by regulating ZmPOD52 expression

Abstract

ZmWRKY107 plays a role in salt stress response by binding to the ZmPOD52 promoter and regulating its gene expression, providing a WRKY candidate gene for improving salt stress resistance in maize. Plants are affected by various environmental factors throughout their growth stages, with salinity being a particularly significant stressor. WRKY transcription factors play an essential role in plant responses to stress. In this study, ZmWRKY107 in maize (Zea mays L.) was revealed to belong to the WRKY transcription factor group II subfamily. ZmWRKY107 expression was induced to varying degrees by salt stress. ZmWRKY107 was localized in the nucleus and showed transcriptional activity in yeast. Additionally, luciferase assays and yeast one-hybrid experiments confirmed that ZmWRKY107 binds specifically to the W-box (TTGACC) sequence. Comparative analyses indicated that wrky107 mutants are more sensitive to salt stress than B73, with decreased relative water content and peroxidase (POD) and catalase activities, but increased malondialdehyde accumulation and relative electrolyte leakage. To explore the underlying molecular mechanisms, we conducted transcriptome sequencing (RNA-seq) and quantitative real-time PCR analyses to clarify how ZmWRKY107 responds to salt stress and affects the expression of stress response-related genes. Moreover, luciferase reporter gene assays and yeast one-hybrid experiments showed that ZmWRKY107 can bind directly to the W-box element in the ZmPOD52 promoter. This interaction likely forms part of a regulatory network that activates ZmPOD52 expression, contributing to the maize response to salt stress. In conclusion, we propose a mechanism for the maize response to salt stress involving the ZmWRKY107-ZmPOD52 molecular module, thereby enhancing our understanding of how WRKY transcription factors regulate salt tolerance in maize.

Keywords: ZmPOD52; ZmWRKY107; Maize; RNA-seq; Salt stress; WRKY transcription factor.