Acetic Acid: a Selective Nematicidal Metabolite From Culture Filtrates of Paecilomyces Lilacinus (Thom) Samson and Trichoderma Longibrachiatum Rifai

TLDR: The nematotoxic activity, efficient against plant-parasitic species, found in the culture filtrates of two Hyphomycetes: Paecilomyces lilacinus (nematophagous fungus) and Trichoderma longibrachiatum was characterized and selective permeability of different cuticle zones of nematodes for non-charged substances (non-polar) was confirmed.

Abstract: The nematotoxic activity, efficient against plant-parasitic species, found in the culture filtrates of two Hyphomycetes: Paecilomyces lilacinus (nematophagous fungus) and Trichoderma longibrachiatum was characterized. Purification was performed by distillation and liquid chromatography and identification by gas-chromatography coupled with a DCI system (dynamic headspace). The active substance has been identified as acetic acid which, produced abundantly during fungal growth in liquid medium (up to 0.044 mols of CH 3 COOH per culture filtrate litre), inhibited movement of infesting juvenile nematodes. These results were confirmed by comparative studies using the commercial molecule as for the 1 H NMR as the biological tests. The toxic activity appeared only when the carboxylic function was in its undissociated form, hence the real interest of pH when studying this nematicidal activity. A study of the literature confirmed the selective permeability of different cuticle zones of nematodes for non-charged substances (non-polar).