Effects of activities and gene expression of pathogenesis-related proteins in muskmelon fruit inoculated with Alternaria alternata

Jiashi muskmelon and 86-1 muskmelon species with the characteristics of disease resistance were used as experiment material.This study was aimed to the activities of CHT, GLU and the gene expression rules for CHT and GLU in muskmelon fruits inoculated with A.alternata were analyzed.Jiashi muskmelon and 86-1 muskmelon were inoculated with 20 μL A.alternata spore suspension, inoculation with 20 μL of sterile water as a blank control, the materials were transferred to cold storage at6⁸ ℃, determination of lesion size, the activities of CHT, GLU and the gene expression of CHT and GLU.The results showed that the incidence and the lesion size of Jiashi muskmelon were lower than that of 86-1 muskmelon during the inoculated with A.alternata after 15 days.During the infection period, the activities of CHT, GLU was significantly increased with a trend from rise to decline. The peak of activities for CHT, GLU revealed of 21 d, 18 d. The activities of CHT, GLU in Jiashi melon significantly higher than 86-1 muskmelon Jiashi muskmelon to resist the infection of A.alternaria by enhancing the activity of protease and maintaining the enzyme activity at a higher level. The relative expressions for CHT1, CHT2, GLU were higher in Jiashi muskmelon than 86-1 muskmelon during the whole infection period.The expression levels of CHT1, CHT2 and GLU were significantly higher than 86-1 melon, and the expression level of CHT1, CHT2 and GLU was the highest in storage at 18, 18 and15 days.The relative expression of protein-related protein and gene expression were positively correlated with lesion diameter for 0²1 d.These results suggest that the pathogenesis related proteins play a key role in the early and middle stage of plant pathogen resistance.