A novel transcription factor PtMYB77 from Pinellia ternata enhances heat tolerance in Arabidopsis by inducing early expression of heat shock factor genes

High summer temperatures significantly reduce the yield of Pinellia ternata , a medicinal herb that ranks among the top ten export materials from Japan and China. Here, we identified 188 MYB transcription factor genes in P. ternata and conducted a comprehensive analysis of their chromosomal distribution, duplication events, phylogeny, gene structure, and motif composition. Exposure to heat stress triggered up to a 30-fold increase in the expression of PtMYB77 (1R-MYB). To confirm its role in thermotolerance, PtMYB77 was expressed in Arabidopsis. The transgenic plants exhibited superior germination, longer roots, and enhanced antioxidant enzyme activities under heat stress compared to the wild-type. Furthermore, these transgenic plants showed an early induction of heat shock factor genes following heat treatment, suggesting a potential priming mechanism that prepares the plants for subsequent heat stress. This mechanism may provide new insights into the role of 1R-MYB in the response to heat stress. • 188 MYB TFs were identified in P. ternata. • Heat stress triggered up to a 30-fold increase in PtMYB77 (1R-MYB) expression. • Role of PtMYB77 in thermotolerance was confirmed by expressing it in Arabidopsis. • PtMYB77 triggered early induction of HSP genes in transgenic Arabidopsis plants. • This study provides new insight into the role of 1R-MYB in the heat stress response .