Pochonia chlamydosporia: Multitrophic Lifestyles Explained by a Versatile Genome

Abstract

The nematophagous fungus Pochonia chlamydosporia (Goddard) Zare & Gams is a facultative parasite of nematode females and eggs. This fungus has a world-wide distribution and has the capacity to survive in the absence of the nematodes. Pochonia chlamydosporia is rhizosphere competent and can colonize the rhizosphere of crops of economic importance, such as tomato and barley. The infection of nematode eggs by P. chlamydosporia requires adhesion, differentiation of appressoria, and penetration of their egg shells. Since the 1980s, proteases have been described as the main group of enzymes that the fungus uses to penetrate nematode eggs. Recent studies found that these genes are also expressed when the fungus endophytically colonizes barley roots. The genome of the fungus was sequenced in 2014, this being the first publicly available genome of a fungus parasite of nematode eggs. Since then, many publications based on the fungus genome have been published. Study of the major gene families in the genome shows the tools that the fungus uses in its different lifestyles. Transcriptomic studies using DNA microarrays and RNA-seq have been done to study the molecular mechanisms that regulate endophytic colonization of Pochonia chlamydosporia. A general analysis of the genome allowed us to identify a large number of carbohydrate active enzymes (Cazy) which help the fungus in colonizing plants and infecting nematodes.