Molecular Mechanism of Nematophagous Fungi Infection of Nematodes

Abstract

Nematophagous fungi are an important group of soil microorganisms that can suppress the populations of plant-parasitic nematodes. At present, the detailed molecular pathogenic mechanisms against nematodes by nematophagous fungi have not yet been fully elucidated. However, increasing evidence show that extracellular hydrolytic enzymes including proteases, collagenase, and chitinase may be involved in nematode-cuticle penetration and host-cell digestion. Recently, the crystal structures of proteases (Ver112 and PL646) and chitinase CrChi1 from nematophagous fungi were resolved, which can help us to identify the active site residues and to elucidate the catalytic mechanism of these enzymes involved in infection against hosts. The expression and regulation of protease PrC from Clonostachys rosea by different environmental conditions has also been reported. The genome of Arthrobotrys oligospora has been sequenced, and a model of nematode trap formation in A. oligospora suggested; thus the genome data may serve as a roadmap for further investigations into the interaction between nematode-trapping fungi and their host nematodes, providing broad foundations for research on the biocontrol of pathogenic nematodes. In this chapter, we describe the characterization of extracellular enzymes from nematophagous fungi, the expression and regulation of serine protease prC in Clonostachys rosea, and the genome and proteomic analyses of the nematode-trapping fungus Arthrobotrys oligospora.