Molecular Mechanism Of Exogenous Put Treatment Mediated Cell Wall Metabolic Key Gene VcPG1 Expression Regulating Postharvest Blueberry Fruit Softening

Blueberry（Vaccinium spp.）is a small berry.Because of its nutritional value and unique taste by consumers love.Due to its own structural characteristics,it is easy to soften after harvest,resulting in economic losses.Put exists in higher biological organisms and participates in a variety of reactions in different species.It is used in the post harvest treatment of fruits.Through the treatment of blueberry with exogenous Put,the changes of decay incidence,firmness and internal nutrients of blueberry fruit were studied,and to clarify the regulation effect of exogenous Put treatment on the quality of blueberry fruits.Softening was found to be the main quality deterioration phenomenon of blueberry fruit during storage,cell wall metabolism related pathways were locked,and the effects of exogenous Put treatment on cell wall metabolism of blueberry fruits were explored.Related enzyme activities and gene expression levels were determined,and key softening genes were preliminarily identified.Function verification of key softening genes was carried out,and preliminarily screened the transcription factors that may bind to the key genes.The main results are as follows:1.During the shelf period at room temperature,after exogenous Put treatment,the decay incidence of blueberry fruits was reduced,firmness decreased slowly.The fruit firmness decreased from 1.213 N to1.043 N,and the sarcocarp firmness decreased from 0.29 N to 0.24 N.Solid/titratable acid,total phenols,flavonoids and anthocyanins were maintained,economic losses were reduced by about 10%,and fruit quality was maintained.2.After Put treatment,focus on cell wall metabolic pathways,the degradation rate of propectin was slowed down,and the cell wall metabolism related enzymes PG,β-Gal,β-Glu activity were reduced,the expressions of cell wall metabolism related genes Vc PG1,Vc PE,Vcβ-Gal,Vcβ-Glu,Vc PL were decreased,the rate of softening was inhibited,and preliminarily locked out the key gene Vc PG1 of cell wall metabolism.The full length sequence of coding region was cloned,with a total of 987 bp.A total of 984 bp promoter sequences were cloned.The transient overexpression test showed that Vc PG1 was the key gene to promote blueberry softening.The structure of Vc PG1 protein sequence was analyzed,the secondary and tertiary structures of Vc PG1 protein,and was predicted to be hydrophobic protein.The minimum inhibitory concentration of Ab A of p Ab Ai-Vc PG1 was 100 ng m L^-1.By predicting the binding sites of Vc PG1promoter to key transcription factors,the transcription factors that may bind to Vc PG1 gene were preliminarily screened,and the mechanism of action of Vc PG1 was discussed from the molecular perspective.3.Through the experiment of different concentrations of exogenous Put combined with cold storage treatment,the screening results showed that the effect of 1 mmol L^-1Put treatment was better.On the 60 th day of cold storage,the firmness of fruit and sarcocarp was significantly higher than that of the control and other concentrations,which significantly delayed the softening of Postharvest blueberry fruits during cold storage.