Comparative Genomic Analysis of the SlDREB2 Gene Family in Solanum lycopersicum under Low Temperature Stress

Cold stress is a primary environmental factor limiting tomato growth and crop yields. The Dehydration-Responsive Element-Binding (DREB) transcription factors play crucial roles in plant acclimation to abiotic stresses, particularly cold. In this study, we performed a genome-wide comparative analysis of the SlDREB2 gene family in Solanum lycopersicum. We identified five distinct SlDREB2 genes and analyzed their phylogenetic relationships, conserved domains, and promoter regions. Under simulated cold stress (4°C), qRT-PCR analysis revealed differential expression patterns, with SlDREB2A exhibiting a rapid 15-fold upregulation. Transgenic tomato lines overexpressing SlDREB2A showed higher relative water content, elevated proline accumulation, and reduced levels of reactive oxygen species (ROS) compared to wild-type controls. Physiological evaluations demonstrated that SlDREB2A overexpression enhances cell membrane stability and preserves PSII photosynthetic activity. This study demonstrates the critical role of the SlDREB2 family in low temperature resilience and proposes SlDREB2A as a promising genetic candidate for cold-tolerant tomato breeding.