Genome-wide identification and stress-responsive expression profiling of the HSP70 gene family in Pinellia ternata

Heat shock protein 70 (HSP70) plays crucial roles in plants' responses to abiotic stresses. In this study, we performed a genome-wide identification and comprehensive characterization of the HSP70 gene family in the medicinal herb Pinellia ternata. In total, 21 PtHSP70 genes were identified and classified into distinct subfamilies via phylogenetic analysis. Structural and motif analyses revealed conserved domain architectures, whereas promoter examination indicated the enrichment of stress- and hormone-responsive cis-elements. Ka/Ks and collinearity analyses indicated that the PtHSP70 genes have primarily evolved under purifying selection and share extensive synteny with orthologs in related monocot species. Expression profiling revealed that most PtHSP70 genes were significantly upregulated in response to both heat (35 °C) and cold (8 °C) stress. The result of tissue-specific expression showed most PtHSP70 genes were highly expressed in the tubers. PtHSP70 genes responded differentially to methyl jasmonate (MeJA) and abscisic acid (ABA) treatments, with five PtHSP70 genes being significantly upregulated by both ABA and MeJA. Our findings provide a foundation for further functional studies of PtHSP70 genes in abiotic stress tolerance and offer valuable insights for molecular improvement of P. ternata.