Diversity of fungal communities in the soil of three nurseries in Tlemcen (North-West of Algeria)

Fungi play a central role in most ecosystems and seem to dominate the microbial biomass in soil habitats, where they are important decomposers and occupy a notable position in the natural carbon, nitrogen and phosphorus cycles. Despite the fact that fungal species have been studied in several contexts, the diversity of some soil fungal species in nurseries is still unknown. This study aimed to explore the diversity of fungal species occurring in nursery soil of Tlemcen province (North-west of Algeria) and to test the antagonist effect of some isolates of Trichoderma sp. on species of the genus Pythium and those of Diplodia. Soil and root samples from young seedlings showing symptoms of oomycete infection and other fungal were collected in three nurseries of Tlemcen region. Following a soil baiting using fresh ornamental leaves, three Phytophthora species were isolated and identified based on morphology and microscopic observation. About the others groups, the dilution method using physiological water, revealed the presence of significant fungal biodiversity on the PDA medium. Twelve fungal species and five oomycetes have been isolated and identified, namely: D. sapinea, Lasio. exigua, F. oxysporum, Aspergillus sp., Penicellium sp., Mucor sp., Trichoderma sp., Alternaria sp. P. cinnamomi, P. gonapodyides, P. ramorum, Py. ultimum and Py. Polare. Significant antagonist activity was recorded for isolates of Trichoderma sp. against Pythium sp. and Diplodia sp.