Bacteria can mobilize nematode-trapping fungi to kill nematodes
نویسندگان
چکیده
In their natural habitat, bacteria are consumed by bacterivorous nematodes; however, they are not simply passive preys. Here we report a defensive mechanism used by certain bacteria to mobilize nematode-trapping fungi to kill nematodes. These bacteria release urea, which triggers a lifestyle switch in the fungus Arthrobotrys oligospora from saprophytic to nematode-predatory form; this predacious form is characterized by formation of specialized cellular structures or 'traps'. The bacteria significantly promote the elimination of nematodes by A. oligospora. Disruption of genes involved in urea transport and metabolism in A. oligospora abolishes the urea-induced trap formation. Furthermore, the urea metabolite ammonia functions as a signal molecule in the fungus to initiate the lifestyle switch to form trap structures. Our findings highlight the importance of multiple predator-prey interactions in prey defense mechanisms.
منابع مشابه
Screening of Soil and Sheep Faecal Samples for Predacious Fungi: Isolation and Characterization of the Nematode-Trapping Fungus Arthrobotrys oligospora
Over one-year period, 150 pasture soil samples and 138 sheep faecal samples, collected from different parts of Iran were screened for the presence of nematophagous fungi. The samples were cultured at 25ºC on chloramphenicol-2% water agar (CHF-WA) plates in the presence of Haemonchus contortus third stage larvae (L3) and checked over a two-month period for characteristic conidia, conidiophores a...
متن کاملGenomic Mechanisms Accounting for the Adaptation to Parasitism in Nematode-Trapping Fungi
Orbiliomycetes is one of the earliest diverging branches of the filamentous ascomycetes. The class contains nematode-trapping fungi that form unique infection structures, called traps, to capture and kill free-living nematodes. The traps have evolved differently along several lineages and include adhesive traps (knobs, nets or branches) and constricting rings. We show, by genome sequencing of t...
متن کاملRhizosphere Colonization and Control of Meloidogyne spp. by Nematode-trapping Fungi.
The ability of nematode-trapping fungi to colonize the rhizosphere of crop plants has been suggested to be an important factor in biological control of root-infecting nematodes. In this study, rhizosphere colonization was evaluated for 38 isolates of nematode-trapping fungi representing 11 species. In an initial screen, Arthrobotrys dactyloides, A. superba, and Monacrosporium ellipsosporum were...
متن کاملNematode-Trapping Fungi Eavesdrop on Nematode Pheromones
The recognition of molecular patterns associated with specific pathogens or food sources is fundamental to ecology and plays a major role in the evolution of predator-prey relationships. Recent studies showed that nematodes produce an evolutionarily highly conserved family of small molecules, the ascarosides, which serve essential functions in regulating nematode development and behavior. Here,...
متن کاملEvolution of parasitism in nematode-trapping fungi.
We are studying the evolution of parasitism in a group of soil-living ascomycetes that can grow as saprophytes as well as parasites by forming special morphological structures called traps. Analyses of 18S ribosomal DNA sequences have shown that these fungi form a monophyletic and isolated clade among the ascomycetes. The phylogenetic patterns within this clade are concordant with the morpholog...
متن کامل