Effect of SS-toxin, a metabolite of Stemphylium solani, on H+-ATPase activity and standard redox system in plasma membranes from seedlings leaves of garlic (Allium sativum)

摘要

Leaf blight of garlic (Allium sativum) is a severe disease in garlic-growing regions. SS-toxin is a newly described non-proteinaceous toxin produced by the phytopathogenic fungus, Stemphylium solani, the cause of garlic leaf blight. In this study, the effects of SS-toxin on the H+-ATPase activity and standard redox activity in the plasma membranes isolated by aqueous polymer two-phase partitioning from garlic seedling leaves were studied in vitro. The H+-ATPase activity, NADH oxidation rate and Fe(CN)₆3− reduction rate of the plasma membranes isolated from susceptible and resistant cultivars were all inhibited in a dose-dependent manner. Our results suggest that, under in vitro conditions, the plasma membrane H+-ATPase and standard redox system can be both the cellular targets of SS-toxin.