Functional Analysis of Abscisic Acid-Stress Ripening Transcription Factor in Prunus persica f. atropurpurea

Red-leaf peach (Prunus persica f. atropurpurea) is an important subtropical fruit crop, and an ideal species for leave color quality research because of the substantial changes that occur during development. It experiences lots of stresses during growth. To understand the mechanism of plant anti-stress, ASR [abscisic acid (ABA), stress, ripening-induced] genes, which are unique to plants, were induced under the application of ABA, stress, and ripening. In this study, we showed that in peach leaves stress could induce antioxidant enzyme activity and anthocyanin production, as well as biosynthesis gene expression, but decrease chlorophyll content. One ASR isoform identified from peach contained ABA stress- and ripening-induced proteins and a water-deficit stress-induced protein (ABA/WDS) domain, and had a high genetic relationship with other species of ASRs. ASR transcript levels were increased under abiotic and biotic stresses, and were also induced by sucrose and ABA. ASR bound the promoter of the hexose transporter, which contained four sugar boxes induced by sucrose that activated downstream gene expression. Overexpression of the PpASR gene conferred tolerance to stresses in tobacco. Transient expression of PpASR in tomato promoted fruit softening and ripening. Taken together, this study provides new evidence on the important role of ASR in cross-signaling between ABA and sucrose to regulate peach anti-stress. The findings of this study also provide new insights into the regulatory mechanism underlying fruit development.