Transcriptome Analysis Identifies OsWRKY26 as a Key Regulator for Cold Tolerance at the Seedling Stage in Rice

Cold stress poses a major threat to rice productivity and grain quality. WRKY transcription factors, one of the largest plant-specific gene families, play crucial roles in plant responses to abiotic stress. However, their functions in cold responses and the evolutionary mechanisms underlying cold adaptation during the long-term domestication of cultivated rice remain poorly understood. Here, we identified <i>OsWRKY26</i> as an important regulator of cold adaptation in <i>japonica</i> subspecies through transcriptome sequencing (RNA-seq). Subcellular localization analysis showed that the OsWRKY26 protein is localized to the nucleus under both normal and cold-stress conditions. Expression analysis indicated that <i>OsWRKY26</i> is significantly upregulated at low temperature. Moreover, transgenic validation and measurements of multiple physiological traits demonstrated that <i>OsWRKY26</i> positively regulates seedling cold tolerance in rice. Evolutionary analyses of <i>OsWRKY26</i> and <i>OsMYB2</i>, a previously reported positive regulator of rice cold tolerance, suggested that these two genes diverged in wild rice and subsequently experienced directional selection in temperate <i>japonica</i> cultivated in high-altitude and high-latitude regions. Together, these findings provide a theoretical foundation for dissecting cold-tolerance mechanisms in rice, as well as promising genetic resources for molecular breeding in low-temperature environments.