PpeERF115 regulates peach fruit ripening by increasing polyamine turnover through up-regulation of genes involved in polyamine synthesis and catabolism

Polyamines (PAs) are anti-senescence agents that promote maintenance of fruit quality after harvesting. Many studies have reported increases in PA synthesis and catabolism and decreases in PA levels during fruit ripening. However, few reports have addressed the modulation mechanisms of PA metabolism during fruit maturation. In this report, we found that the peach (Prunus persica L.) transcription factor PpeERF115 directly bound to the PpeADC1 and PpePAO1 promoters, activating these genes. Silencing PpeERF115 enhanced spermidine (Spd) and spermine (Spm) accumulation, reduced putrescine (Put) content, decreased ethylene production, suppressed the respiratory rate, promoted maintenance of fruit firmness, and delayed peach ripening. Conversely, fruit over -expressing PpeERF115 showed significantly reduced Spd and Spm accumulation and clear increases in Put levels. RNA-sequencing analysis indicated that PpeADC1, PpeCuAO2, and PpePAO1 were dramatically down -regulated in PpeERF115-known out fruit, whereas PpeSAMDC1 was significantly up-regulated. This study is the first to show that PpeERF115 regulates peach ripening by increasing PA turnover through up-regulation of PA synthesis and catabolism. These results extend our comprehension of the coordination between ethylene and PAs during regulation of fruit maturation.