Antifungal activity of a synthetic cationic peptide against the plant pathogens Colletotrichum graminicola and three Fusarium species

Abstract

A small cationic peptide (JH8944) was tested for activity against a number of pathogens of agricultural crops. JH8944 inhibited conidium growth in most of the tested plant pathogens with a dose of 50 µg/ml, although one isolate of Fusarium oxysporum was inhibited at 5 µg/ ml of JH8944. Most conidia of Fusarium graminearum were killed within 6 hours of treatment with 50 µg/ ml of JH8944. Germinating F. graminearum conidia required 238 µg/ml of JH8944 for 90% growth inhibition. The peptide did not cause any damage to tissues surrounding maize leaf punctures when tested at a higher concentration of 250 µg/ml even after 3 days. Liposomes consisting of phosphatidylglycerol were susceptible to leakage after treatment with 25 and 50 µg/ ml of JH8944. These experiments suggest this peptide destroys fungal membrane integrity and could be utilized for control of crop fungal pathogens.