Effects of Alternaria alternata infection on active oxygen metabolism in different tissues of melon
[Objective]To study the change trend of ROS and the activity of active oxygen metabolizing enzymes in melon tissues during the onset of black spot disease of Jiashi melon and 86-1 melon after inocula-tion with Alternaria alternata and discuss the relationship between the disease development and the change trend of ROS and the activity of active oxygen metabolizing enzymes.[Methods]The melon fruits of Jiashi and 86-1 were used as experimental materials to study the incidence of melon fruits,and the changing trend of the generation and removal of reactive oxygen species(ROS)in melon fruits when Alternaria alternata was in-jured and inoculated.[Results]After melon fruit was infected by Alternaria alternata,the contents of reactive oxygen species(H2O2 and O2-)increased rapidly,and the activities of SOD and CAT increased,which re-duced the production of MDA.The activities of SOD and CAT increased slowly in the early stage of infection,increased rapidly in the middle stage of infection,and decreased rapidly in the late stage of infection.During the whole storage period,the activities of SOD and CAT in Jiashi melon were higher than those in 86-1 mel-on,and the activities of SOD and CAT in the peel of both melons were higher than those in the pulp,and the activities of SOD and CAT in the two melon inoculation groups were higher than those in the control group.[Conclusion]During the storage period,the level of reactive oxygen species metabolism was closely related to the ability of the melon to defend against Alternaria alternate.The resistance of Jiashi melon is stronger against Alternaria alternate than that of 86-1 melon,especially in the middle and late storage.The disease resistance of Jiashi melon is stronger than that of 86-1 melon,and the skin disease resistance is stronger than that of pulp.
muskmelonAlternaria alternatainfectionreactive oxygen species