Elicitor and Suppressor of Pisatin Induction in Spore Germination Fluid of Pea Pathogen, Mycosphaerella pinodes

Abstract

Both elicitor and suppressor of pisatin accumulation in pea leaves were found in the pycnospore germination fluid of Mycosphaerella pinodes, a pathogenic fungus of pea plant. The elicitor was a high, whereas the suppressor was a low molecular weight substance. The suppressor counteracted the activity of elicitor. Purification of suppressor from low molecular weight fraction by gel filtration and TLC gave two active components, F2 and F5. These substances were found to be low molecular weight peptides because they showed positive color reaction with ninhydrin and Lowry reagents. Both F2 and F5 inhibited pisatin accumulation in pea leaves induced by inoculation with non-pathogens, Erysiphe graminis hordei and Stemphylium sarcinaeforme. The activity of F5 was stronger than F2. F5 inhibited completely the accumulation of pisatin at a concentration of 50μg/ml, and rendered pea leaves accessible to S. sarcinaeforme.