PpERF113 And PpERF115 Regulates The Expression Of PpPAO1 Mediated Polyamine Catabolism And Functional Analysis In Peach Fruit Ripening

Peach is one of the most popular fruits.Peach is a kind of fruit with specific respiratory climacteric.Peach fruit is easy to rot and deteriorate,and its storage period is short,which greatly reduces its economic value.Some studies have shown that exogenous polyamines can delay the senescence of peach and have the effect of storage and preservation.The content of polyamines was higher in the early stage of peach fruit development and decreased rapidly with fruit ripening.Previous studies have shown that polyamine decomposition mediated by polyamine oxidase gene PpPAO1 is the main reason for the decrease of polyamine content during peach fruit ripening.At present,the role of PAO-mediated polyamine decomposition in peach fruit ripening has not been reported.In this study,polyamine decomposition inhibitor aminoguanidine(AG)was used to treat soft solute ’Huangshuimi’ peach and hard solute ’Yushuangmi’ peach fruit,and the fruit firmness,endogenous ethylene release and respiration rate were measured.The function of PpPAO1 gene in polyamine decomposition and peach fruit ripening was verified by VIGS.Using transcriptome data analysis,it was found that there was are significant correlation between the expression of ERF family transcription factor PpERF113、PpERF115 and PpPAO1.The molecular mechanisms of PpERF113、PpERF115 regulating PpPAO1 expression,polyamine decomposition and peach fruit ripening were further verified by yeast one-hybrid,LUC and VIGS techniques.The main results are as follows:1.Polyamine catabolism inhibitor treatment could delayed peach fruit ripening of soft solute ’Huangshuimi’ peach and hard solute ’Yushuangmi’ peach fruit.After polyamine catabolism inhibitor treatment,the fruit firmness of soft solute’Huangshuimi’ peach and hard solute ’Yushuangmi’ peach were significantly higher than those of the control,while the endogenous ethylene release and respiration rate were significantly lower than those of the control.The results showed that polyamine catabolism inhibitor treatment could inhibit the decomposition of endogenous polyamines,delay peach fruit softening,decrease ethylene production and respiration rate,and prolong the shelf life of soft solute ’Huangshuimi’ peach and hard solute’Yushuangmi’ peach.Silencing PpPAO1 could increase the accumulation of polyamines and delay the ripening of peach fruit.The expression of PpPAO1 was up-regulated with the ripening of peach fruit,and the subcellular localization showed that the gene was located in apoplast.Over-expression of PpPAO1,in tobacco showed that the contents of Put,Spd and Spm in transgenic tobacco were significantly lower than those in the control.DAB staining showed that the content of polyamine decomposition product H2O2 in transgenic tobacco was higher than that in the control,indicating that the gene was involved in the oxidative decomposition of polyamines.Using VIGS technique to silence PpPAO1,in peach fruit,it was found that the polyamine accumulation of transgenic peach fruit was significantly increased,the fruit firmness was significantly higher than that of the control,while the ethylene release and respiration rate were significantly decreased,and the ripening and softening of peach fruit was significantly delayed.It is suggested that inhibition of polyamine decomposition mediated by PpPAO1 gene can delay peach fruit ripening.2.PpERF113、PpERF115 regulates the oxidative decomposition of polyamines and peach fruit ripening by promoting the expression of PpPAO1 gene.Yeast one-hybrid and LUC experiments were used to verify the transcriptional regulation of PpPAO1 gene by PpERF113、PpERF115.The results showed that PpERF113、PpERF115 could combine with PpPAO1 gene promoter to promote its expression.It was found that the expression of PpPAO1 gene in transgenic peach fruit was significantly decreased,polyamine accumulation was significantly increased,fruit firmness was significantly higher than that of control,ethylene production and respiration rate were significantly decreased,and peach fruit ripening was delayed by VIGS silencing peach fruit PpERF113、PpERF115,It is suggested that PpERF113、PpERF115 regulates the oxidative decomposition of polyamines and peach fruit ripening by regulating the expression of PpPAO1 gene.This study verified the function of polyamine decomposition in peach fruit ripening,and analyzed the transcriptional regulation mechanism of PpPAO1,the key gene of peach polyamine decomposition,which will provide an important theoretical reference for the research and development of peach storage and fresh-keeping technology.