Chitinolytic capacity of fungi isolated from agricultural soils infested with the root-knot nematode (Meloidogyne spp.) in Puerto Rico

Abstract

In order to identify microorganisms with potential for the control of the root-knot nematode Meloidogyne incognita, the chitinolytic capacity of the mycoflora associated with the nematode was determined in agricultural soils in the municipalities of Adjuntas, Barranquitas, Jayuya and Maricao, Puerto Rico. Out of 74 fungal isolates, 19 showed chitinolytic capacity in vitro: Trichoderma sp., T. harzianum, Gliocladium roseum, Paecilomyces lilacinus, P. marquandi (Types I, II and III), Dihetetospora chlamydosporia, Acremonium fusidioides, Myrothecium verrucaria, M. roridum, Chaetomium globosum, Metarrhizium anisoptiae, Penicillium melinii, P. purpurogenum, P. simplicissimum, P. thomii, Scopulariopsis sp. and Aspergillus fumigatus. Soil pH, texture and temperature were similar in all localities. The variation among localities in organic matter content, relative soil humidity and soil elements (phosphorus, potassium, calcium, magnesium and manganese) affected the distribution of fungi species in each locality. These organisms have great potential as nematode biocontrol agents since most of them have been found associated with eggs, larvae and females of Meloidogyne spp. and Heterodera spp. They are endemic to the area and have good chitinoliytic capacity.