Identification and Drought-Responsive Expression Analysis of the ZmSPS Gene Family in Maize and Preliminary Investigation of the ZmSPS3 Regulatory Network

Sucrose phosphate synthase (SPS) is a key rate-limiting enzyme that regulates carbon partitioning and stress tolerance in plants. In this study, we systematically characterized the SPS gene family in maize (Zea mays L.) and identified key members and their interaction networks involved in drought responses. A total of seven ZmSPS genes were identified through genome-wide bioinformatics analyses. Motif composition, gene structure, phylogenetic relationships, and synteny analyses indicated that the ZmSPS gene family is highly conserved among monocot species. Promoter analysis revealed that the upstream regions of ZmSPS genes are enriched with multiple stress responsive cis-acting elements. Drought stress treatments combined with quantitative real-time PCR (RT-qPCR) analyses showed that the expression of ZmSPS3 was significantly upregulated with increasing stress duration. Furthermore, yeast two-hybrid assays demonstrated that ZmSPS3 physically interacts with protein kinases and F-box proteins. These interactions suggest a potential involvement of ZmSPS3 in post-translational modification and protein stability regulation during osmotic stress. As a potential candidate gene responsive to drought, ZmSPS3 provides a preliminary basis for understanding the complex drought-response networks in maize.