Resistance difference of muskmelon fruit on infection of Alternaria alternata

Take Jiashi muskmelon and 86-1 muskmelon as the experimental materials,the difference of resistance ability of muskmelon to pathogens during storage was studied in this paper. Six holes were made with a hole punch at regular distance on the equatorial part of fruit. And every hole inoculated with 20 μL A.alternata,then the muskmelon was stored in cold storage at 7 ℃. The lesion diameter of pericarp and sarcocarp were measured. The activities of chitinase,β-1,3-glucanase,phenylalanine ammonia-lyase,cinnamic acid hydroxylase and 4-coumaric acid-coenzyme A ligase were studied. The results indicated that during the storage period,the lesion diameter of 86-1 muskmelon was greater than that of Jiashi muskmelon,and the sarcocarp lesion diameter was greater than the pericarp. After inoculated with the A.alternata,both the pathogenesis-related proteins and the phenylpropanoid metabolizing enzymes were higher than CK,which showed the trend of rising first and then decreasing during the storage period. According to the research,the activities of disease-related enzymes in Jiashi muskmelon were higher than that of 86-1 muskmelon,which resulted the former was more resistant to disease than the latter. Pericarp enzyme activities were higher than the sarcocarp,so the pericarp resistance was stronger than the sarcocarp.