Linking organic metabolites as produced by Purpureocillium lilacinum 6029 cultured on karanja deoiled cake medium for the sustainable management of root-knot nematodes

Abstract

Root-knot nematodes pose a serious threat to agriculture and forest systems, causing significant losses of the crop worldwide. A wide range of chemical nematicides has traditionally been used to manage phyto-nematodes. However, due to their ill effects on the environment, biological control agents (BCAs) like Purpureocillium lilacinum that exhibit antagonistic effects on root-knot nematodes are preferred. The current study focused on identifying nematicidal metabolites produced by the fungus Purpureocillium lilacinum cultivated on akaranja deoiled cake-based liquid medium through bioactivity-guided fractionation against Meloidogyne incognita. Column chromatography of the ethyl acetate extract of fungal filtrate exhibited the most potent fraction (fraction 14-15), giving 94.6% egg mass hatching inhibition on the 5th day and a maximum nematicidal activity of 62% against second-stage juveniles after 48 h at 5000 mg/L. Gas chromatography coupled with mass spectrometry (GC-MS) analysis of this fraction revealed five major compounds, viz., 2-ethyl butyric acid, phenyl ethyl alcohol, benzoic acid, benzene acetic acid, and 3,5-Di-t-butylphenol. These biocompounds have potential biocontrol applications in agriculture, but further in vivo studies are warranted.