Diversity of nematophagous fungi in Moroccan olive nurseries: Highlighting prey-predator interactions and efficient strains against root-knot nematodes

• Published in: Biological control Vol. 114; pp. 14 - 23
• Main Authors: Aït Hamza, Mohamed, Lakhtar, Hicham, Tazi, Hafssa, Moukhli, Abdelmajid, Fossati-Gaschignard, Odile, Miché, Lucie, Roussos, Sevastianos, Ferji, Zahra, El Mousadik, Abdelhamid, Mateille, Thierry, Boubaker, Hassan
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01-11-2017; Elsevier
• Subjects: Continental interfaces, environment; Culture substrate; Earth Sciences; Ecology; Environmental Sciences; Fungal antagonists; Olive tree; Root-knot nematode; Sciences of the Universe; Root-knot nematode; Culture substrate; Ecology; Olive tree; Fungal antagonists
• ISSN: 1049-9644; 1090-2112
• DOI: 10.1016/j.biocontrol.2017.07.011

•Nematophagous fungi were isolated for the first time in olive nurseries in Morocco.•ITS sequencing revealed five distinct fungal clusters.•The fungal diversity was affected by the north-south climatic gradient.•The occurrences of nematophagous fungi and of root-knot nematodes were correlated.•Talaromyces assiutensis was the most efficient species against Meloidogyne javanica.
Plant-parasitic nematodes are major pests in agriculture. Microbial antagonists such as nematophagous fungi are of great interest for developing alternative biocontrol strategies to replace nematicide use. This study aims to isolate, identify and assess the diversity and the in vitro predatory activity of nematophagous fungi from various olive nurseries in Morocco. A total of 305 soil samples were collected in 25 nurseries in Moroccan olive-producing areas (Jbala, Guerouane, Haouz and Souss). Seventy-three pure fungal strains from nematophagous fungi were recovered from nursery substrates infested with root-knot nematodes. Diversity indices showed that fungi were more numerous in southern regions, whereas fungal communities were more numerically alike in northern regions, partly depending on the occurrence of root-knot nematodes. One fungal strain, Talaromyces assiutensis, killed all Meloidogyne javanica juveniles during in vitro predation tests. Orbiliaceae (Arthrobotrys spp., Drechslerella brochopaga, Monacrosporium spp.) trapped 50 to 80% of juveniles. Purpureocillium and Trichoderma species killed 30 to 50% of juveniles. The diversity of nematophagous communities could be affected by the north-south climate gradient of Morocco, by their nematode prey expansion, and, to a lesser extent, by the habitat origin of the substrates used. Talaromyces assiutensis was the most efficient nematophagous species against M. javanica. The use of native nematophagous fungi is a promising alternative strategy for nematode control in olive nurseries and to prevent nematode introduction into olive orchards.