Root-knot nematodes ( Meloidogyne spp.) are major threats to agriculture worldwide .They are obligate endoparasites that infect a large range of crop plants, leading to considerable economic losses. In the last decades, environmental and human health concerns have steadily reduced the availability of efficient commercial nematicides. Therefore, environmentally friendly substances for effective nematode control are needed to be developed. Endophytes fungi produce biologically active natural products that may be involved in the host-endophyte relationship. Therefore, these microorganisms represent a biotechnological source of bioactive metabolites. As part of our ongoing study of the endophyte biodiversity of the Canarian Laurel Forest, we have obtained an isolate of endophytic fungus Guignardia sp from Perseo indica, one of the dominant Lauraceae tree species reported as a potential source of insect-control agents. This Guignardia sp. endophytic isolate {YCC4) was ferme nted in liquid medium for 20 days. The organic extract was obtained by liquid extraction of culture medium with ethyl acetate. The organic extract (1 µg/µI) showed strong nematicidal in vitro activity against root-knot nematode M. javanica (infective juveniles mortality and long-term egg hatching inhibition effects). Based on bioassay-guided fractionation, three metabolites inducing high nematicidal effects were obtained. Several in vivo tests of organic extract from isolate YCC4 on tomato plants showed strong effects, supressing the infectivity of juveniles and reducing the reproduction index of the nematode population. In conclusion, this study demonstrates that secondary metabolites from endophytic fungi are promising sources of new nematicide products.

Trabajo presentado en Natural Products and Biocontrol Congress, celebrado en Perpignan (France) del 21 al 23 de septiembre de 2016.

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