Soil biodiversity and microbial antagonism for suppression of plant-parasitic nematodes

Plant parasitic nematodes (PPN) cause significant economic losses in agriculture and the use of nematicides is the most common management practice applied today. However, due to the impact of such chemicals, more sustainable methods are needed. Current trends consider the exploitation of indigenous soil microbial communities. In this review we discuss some concepts required for the conservation and management of soil microorganisms, considered as a fundamental natural resource. Co-evolution and co-speciation are basic evolutionary processes of soil taxa involved in soil ecosystem services such as nematode regulation. The microorganisms showing a host-parasite co-evolution hold potential for the insurgence or re-construction of a natural equilibrium in soil, aiming at nematode regulation. The impact on soil microbial diversity of farming intensification and PPN management through nematicides is also discussed. Some examples of soil microbial resources and their impact including antagonists like nematophagous fungi (NF), aquatic parasites and bacteria are also briefly reviewed.