Study On The Effect Of Two Storage Temperatures On The Metabolites Of'Xuxiang' Kiwi Fruit And Its Mechanism Under The Stress Of Botrytis Cinerea

Botrytis cinerea of kiwifruits is one of the most common and serious diseases in the process of storage and transportation of kiwifruit,resulting in huge economic losses.At present,the chemical fungicides are the main measures for the prevention and treatment of kiwifruit Botrytis cinerea,however,the reduced use of chemical bactericides is a trend for humanity demanding for a more healthy diet.Nevertheless,the micro mechanism of pathogenesis on Botrytis cinerea in kiwifruit is not clear.Therefore,it is of great theoretical and practical significance to study the pathogenesis of Botrytis cinerea during the storage of kiwifruits.In this paper,kiwifruits and Botrytis cinerea were used as the raw materials to measure the nutritional quality indexs in kiwifruits after storage and reveal the pathogenesis of Botrytis cinerea in kiwifruit during storage from the level of material metabolism by means of metabonomics and biotechnological methods.Moreover,RT-qPCR(Quantitative Real-time PCR)was used to validate gene expression related to pathogenesis of Botrytis cinerea in kiwifruit.Main contributions of this work are as follows:(1)The determination of ascorbic acid,soluble solids and protein content of kiwifruit without Botrytis cinerea infection after storage at 4? and 20 ? or 7 days.Results showed that soluble solids content decreased by 7.I%.ascorbic acid and protein content increased by 7.7%and 14.8%as compared to kiwifruit stored at 20?,respectively.Metabolite monitoring of kiwifruit without Botrytis cinerea infection after storage at 4 ? and 20 ?for 7 days via LC-MS and GC-MS technology.As compared with kiwifruit stored at 4 ?,a total of 98 up-regulated and 82 down-regulated metabolites was detected,mainly associated with amino acid metabolism,energy metabolism pathway and TCA cycle.The experimental result indicated that kiwifruit storage at 20?would acceleration of energy consumption and amino acid syntheses.(2)Metabolic analysis of kiwifruit infected with Botrytis cinerea after storage at 4 ?and 20 ?for 7 days was carried out using gas chromatography-mass spectrometry(GC-MS)and liquid chromatograph-mass spectrometer(LC-MS)technology.As compared with kiwifruit stored at 4?,the results showed that 102 detectable metabolites of which 60 up-regulated and 42 down-regulated,including 11 kinds of lipid metabolites,8 kinds of amino acid metabolites,6 kinds of carbohydrate metabolites,4 kinds of alcohol metabolites,3 kinds of glycoside metabolites,3 kinds of ketone metabolites,2 kinds of amine metabolites etc,changed significantly(|Fold change|>1.5),which mainly distributed in 12 metabolic pathways,including the pentose phosphate pathway,purine and pyrimidine metabolism,glycolysis,tricarboxylic acid cycle and the synthesis of the three amino acid metabolism,fatty acid synthesis and cofactor metabolism.The results indicated that stress of Botrytis cinerea could affect the synthesis of a series of metabolites related to plant hormones,signal transduction,stress and defense,and storage at 20 ? would enhance metabolite synthesis and gene expression related to host resistanceBy comparing with the Metacyc database,the results showed that five metabolic pathways involved in morbidity of Botrytis cinerea in kiwifruit,including S-methyl-5-thio-a-D-ribose 1-phosphate pathway,PRPP pathway,spermine and spermidine pathway,tetrahydrobiopterin pathway and molybdenum cofactor pathway.RT-qPCR was used to measure the gene expression of PRS4-Q?GhSPMS?GTPCH-2?GmCml and mtnA related to the five pathways.The results show that the expression of genes were positively correlated with related metabolite concentrations.