Changes In Activity Of NADP-ME,PG,β-gal And Expression Of Related Genes In ’Changfu 2’ Fruit During Cold Storage

Apple postharvest softening can affect apple’s sales and processing,and restrict the development of apple industry in China.Based on ’Changfu 2’ apple fruit as the experimental material,the study focused on physiology,quality and changes of cell wall enzymes of postharvest apple,analyzed the gene expression of NADP-ME、PG、β-Gal with fluorescence quantitative PCR technology,providing theory evidence for apple postharvest technology.The results are as follows:(1)The experiment study the relationship between energy level and fruit mature and analyze the energy level,the activity and gene expression of NADP-ME in ’ Chang fu 2’apple fruit during refrigerated storage.These results showed that the content of malate continuously declined during refrigerated storage and pyruvate content accumulate in late storage.The content of ADP and AMP increased in the middle and late storage while the energy charge decreased sharply in the late storage.The content of NADP+ and NADPH first increased and then decreased,and the activities of NADP-ME and SDH declined synchronously indicating that changes on energy level.The analysis of gene expression showed that NADP-ME activity and its gene expression had certain correlation in statistics.(2)Based on ’Changfu 2’ apple as the test material,the firmness,TSS,titratable acid,reducing sufar content and starch content of apple fruit during cold storage(1-4℃)was analyzed in the paper.The results showed that during the cold storage,MDA first decreased to 10mg/g on the 60 d and then increased,fruit firmness and titratable acid of ’Changfu 2’apple fruit decreased remarkably.TSS and reducing sugar content increased slightly in early stage and then decreased slowly and the starch content increased in the middle stage.(3)The activity and gene expression of PG and β-Gal were measured.The activity of PG and the expression of MdPGl and MdPG2 were increased at low temperature,the PG activity and the expression of MdPG2 reached the peak at 120 d,and the expression of MdPGl reached the maximum on the 60 d.The activity of P-Gal increased continuously,and was negatively correlated with fruit firmness.The expression of MdGAL1 and MdGAL2 increased before 60 d,and decreased rapidly.On the whole,the expression of PG and β-Gal gene increased before the enzyme activity,which had an important effect on the activity of the two enzymes.