Metagenomic approach for the analysis of nematode diversity and their use as biological indicators

Soil nematodes are organisms that quickly respond to changes (stress and pollutants) in the environment and can be useful ecological indicators of environmental disruption. Since they occur in any environment containing organic carbon, they do not quickly escape from stressful conditions, occupy key positions in soil food webs and can be classified in easily identifiable trophic groups (Bongers and Ferris, 1999). While there are many indices of biological diversity, specific tools have been developed for nematodes, such as the Maturity Index (MI) and the 3 Enrichment lndex (El). These indices are based on an ecological classification where to each taxonomic family is assigned an ecological value that ranges from l (typical families of polluted soils or sediments) to 5 (typical families of soils or sediments). The lower values (1 and 2) belong to colonizer nematodes (c), i.e. opportunists, characterized by a rapid biological cycle and able to quickly invade unstable or polluted habitats. High values (3 to 5) belong to persister nematodes (p), characterized by a slow reproduction rate. Persisters are more sensitive to pollutants and 1 other disturbances than colonizers, therefore MI also serve to measure the impact of mixtures of pollutants and the effect of their complex interactions with biotic and abiotic environment. The aim of this study was to identify the nematofauna, recovered from three different habitats, at morphological and molecular level to provide useful information on the soil features and any possible disturbances by calculating ecological indexes of soil biodiversity