Role of toxin produced by Alternaria alternata in leaf blight of watermelon and its degradation by biocontrol agents

摘要

Toxin extracted from Alternaria alternata, the causal agent for leaf blight in watermelon (Citrullus lanatus), produced the typical symptoms such as that of the pathogen on detached watermelon leaves and also increased the loss of electrolytes from watermelon leaves. The toxin isolated was glycoproteinaceous in nature. Among the biocontrol agents tested, Bacillus subtilis (BsW1) was found to be highly effective in degradation of the pathogen toxin by utilising the toxin as a sole carbon source.