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 <i>SPS</i> gene family in maize (<i>Zea mays</i> L.) and identified key members and their interaction networks involved in drought responses. A total of seven <i>ZmSPS</i> genes were identified through genome-wide bioinformatics analyses. Motif composition, gene structure, phylogenetic relationships, and synteny analyses indicated that the <i>ZmSPS</i> gene family is highly conserved among monocot species. Promoter analysis revealed that the upstream regions of <i>ZmSPS</i> 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 <i>ZmSPS3</i> 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 <i>ZmSPS3</i> in post-translational modification and protein stability regulation during osmotic stress. As a potential candidate gene responsive to drought, <i>ZmSPS3</i> provides a preliminary basis for understanding the complex drought-response networks in maize.