Transcription Profiling of Potato Leaves in Response to Heat Stress at Single-Cell Resolution.

Potato (Solanum tuberosum L.) is a globally important food crop with considerable nutritional and economic value. Heat stress significantly inhibits potato plant growth and tuber development, constraining the sustainable development of the potato industry. Currently, studies on the cellular-level mechanisms underlying heat adaptation in potato remain relatively scarce. In this study, single-nucleus RNA sequencing was employed to construct single-cell transcriptomic maps of potato leaves under normal and heat stress conditions, yielding 77 344 high-quality nuclei and identifying six major cell types. The results indicated that epidermal cells represented the key cell type in heat-stress response, exhibiting the highest number of differentially expressed genes, whereas vascular cells were positioned in the transition zone of the pseudo-time trajectory and may have been involved in cell differentiation processes. By integrating bulk RNA-seq data, a heat stress response co-expression network was constructed, identifying 12 core transcription factors, with StPIF4 appearing repeatedly. Experimental validation confirmed that heat stress strongly induced StPIF4 expression. Functional studies demonstrated that StPIF4 significantly enhanced potato heat tolerance by improving reactive oxygen species scavenging capacity. This study provided cellular-level insights into the mechanisms underlying potato adaptation to heat stress.