Trapping devices of nematode-trapping fungi: formation, evolution, and genomic perspectives

Nematode-trapping fungi (NTF) are potential biological control agents against plant-and animal-parasitic nematodes. These fungi produce diverse trapping devices (traps) to capture, kill, and digest nematodes as food sources. Most NTF can live as both saprophytes and parasites. Traps are not only the weapons that NTF use to capture and infect nematodes, but also an important indicator of their switch from a saprophytic to a predacious lifestyle. Formation of traps and their numbers are closely related to the nematicidal activity of NTF, so the mechanisms governing trap formation have become a focus of research on NTF. Recently, much progress has been made in our understanding of trap formation, evolution, and the genome, proteome and transcriptome of NTF. Here we provide a comprehensive overview of recent advances in research on traps of NTF. Various inducers of trap formation, trap development, structural properties and evolution of traps are summarized and discussed. We specifically discuss the latest studies of NTF based on genomic, proteomic and transcriptomic analyses.