Ali, G.S., G.E. Harman, and B.I. Reisch. 2000. The interaction of endochitinase, a synthetic peptide ESF12 and resveratrol in controlling fungal growth in vitro. Phytopathology (submitted)

Abstract

The efficacy of two-way combinations of Trichoderma endochitinase (CHIT42), synthetic peptide ESF12 and resveratrol upon the control of growth of Botrytis cinerea and Penicillium digitatum were evaluated in vitro. A colorimetric method for monitoring fungal growth inhibition was compared with the conventional method based on microscopic measurement of spore germination inhibition and germ tube length inhibition. A strong correlation between both methods was found. Subsequent experiments were performed using the colorimetric fungal growth monitoring system. All combinations of CHIT42 + ESF12, CHIT42 + resveratrol, and ESF12 + resveratrol showed additive activity (Interaction Ratios between 0.5 and 1.5) against B. cinerea and P. digitatum. The CHIT42 had EC50 (effective concentration for 50% growth inhibition) values of 60.0 µg mL-1 and 1.13 µg mL-1 against B. cinerea and P. digitatum, respectively. CHIT42 also caused swelling, hyperbranching and bursting of P. digitatum at concentrations as low as 0.09 µg mL-1. The EC50 values of ESF12 were 47.7 µM and 37.7 µM against B. cinerea and P. digitatum, respectively. Resveratrol had EC50 values of 238.0 µM and 453.7 µM against B. cinerea and P. digitatum, respectively. No abnormal morphological changes were observed in either of the species when treated with ESF12 or resveratrol.