PpHSP20-26, a small heat shock protein, confers enhanced autotoxicity stress tolerance in peach

Autotoxicity stress is the principal factor in peach replant problem. Benzoic acid (BA) is known as a critical autotoxin in replant problem, and causes an obvious inhibitory effect on peach growth. Small heat shock proteins (sHSPs) have been reported to play pivotal roles in a variety of physiological and biological processes in various plants. Nevertheless, little is known about the functions and the underlying physiological mechanisms of under autotoxicity stress. Here, we identified of peach () and deciphered its role in BA stress response. was significantly induced by BA treatment. Overexpression of elevated BA tolerance in and peach plants, whereas down-regulation of in peach through virus-induced gene silencing enhanced BA sensitivity. Compared to the control, the overexpressing plants exhibited lower contents of reactive oxygen species (ROS) and higher activities of antioxidant enzymes. Furthermore, regulated the transcripts of stress-responsive genes including , , , , , and in overexpressing and silenced peach plants. Taken together, these data suggest that plays a positive role in peach response to BA stress by, at least partly, regulating ROS metabolism and stress-responsive gene expression. Our findings will be of great importance for further understanding the roles of genes in autotoxicity stress, and assist crop breeding in mitigating replant problem.