Screening of volatile organic compounds from actinobacteria for the control of phytopathogen Colletotrichum gloeosporioides

Abstract

ABSTRACT Colletotrichum gloeosporioides is a fungus responsible for the plant disease called anthracnose, which causes harvest losses. Although pesticides are widely used to control this disease, they tend to lose effectiveness as the phytopathogen develops pesticide resistance. Bacteria with antifungal activity are an alternative in the development of biocontrol agents. Among other biocontrol mechanisms, some bacteria release volatile organic compounds (VOCs) that suppress the growth of some plant pathogens. This study evaluated screening bioassays of VOCs released by 20 strains of actinobacteria isolated from marine environments, as well as their antifungal activity. The Streptomyces sp. (PNM-149) strain showed antifungal activity against Colletotrichum gloeosporioides with 48% of growth inhibition and 67% inhibition of spore production. The VOCs resulting from the bacteria–fungus interaction were collected by static headspace and were then analysed by gas chromatography coupled with mass spectrometry (GC-MS). Seven VOCs including methyl anthranilate and 2-methyl isoborneol were identified as major compounds. Finally, a bioassay with 8 mg/disc of methyl anthranilate showed 100% growth inhibition of C. gloeosporioides.