Analysis of fungal community structure in the rhizosphere of different tomato genotypes grown in suppressive and conductive soils

Suppressive soils are defined as soils capable of containing disease severity and incidence in spite of the presence of pathogens and susceptible host plants: microbial community is responsible for this feature and the microbiota which colonizes the rhizosphere (i.e. the root-surrounding soil) is of particular importance. Fungi play a key role in soil ecosystem and are classified as decomposers, plant pathogens or biocontrol agents. The aim of the present study was to identify the fungal assemblages in the rhizosphere of tomato plants (Solanum lycopersicum), resistant and susceptible to Fusarium wilt, grown either in suppressive or conductive soil. Fungi were isolated with the soil dilution plate method and kept in the biological resource centre (Mycoteca Univarsitatis Taurinesis-MUT). Identification was carried out by both morphological and molecular approach. A total of 375 strains ascribed to 70 species were isolated in pure culture. Preliminary results showed a strong presence of species belonging to the genus Fusarium, Trichoderma and Penicillium. Besides, the suppressive soil appears to be less species-rich than the conductive one. Interesting interactions between individual species are beginning to emerge. In addition, the fungal community in the rhizosphere appears to be influenced by both plant cultivar and soil. In parallel, a culture-independent meta-barcoding analysis (amplification of the ITS2 region) is being carried out to uncover the diversity of unculturable fungi.