Identification and expression analysis of abscisic acid signal transduction genes during peach fruit ripening

To characterize transcriptional regulation of the abscisic acid (ABA) signal transduction pathway during peach fruit early development and ripening, genes encoding the core components of the pathway, including 7 PpPYR (ABA receptor), 10 PpPP2C (type 2C protein phosphatase), and 7 PpSnRK2 (subfamily 2 of SNF1-related kinases), were identified from the peach (Prunus persica) reference genome. PpPYRs, PpPP2Cs, and PpSnRK2s from peach were putative homologous to proteins from tomato and Arabidopsis. Phylogenetic analysis showed that PpPYRs and PpSnRK2s were clustered into three subfamilies/subclasses. Transcript profile indicated that PpPYR2, PpPYR6, and PpPYR7 expression decreased sharply while ABA concentration increased during peach fruit ripening. Expression of PpPP2C4, PpPP2C9, and PpPP2C10 increased along with ABA concentration during fruit ripening. Expression of PpSnRK2.4 and PpSnRK2.6 also increased together with ABA concentration during fruit ripening. Furthermore, PpPP2C10 could interact with PpSnRK2.6 was determined by Yeast two-hybrid and BiFC analyses. The results will improve our understanding of ABA signal transduction genes in peach and lay the foundation for further exploring the mechanisms underlying peach fruit ripening.