Genomic diversity and molecular basis of pathogenicity of novel oomycete pathogens

Oomycetes are fungus-like eukaryotic organisms which can infect plants and animals. Plant pathogenic

oomycetes are generally well studied due to their impact on horticulture, with notable examples including

Phytophthora infestans (which causes potato blight) and Phytophthora ramorum (which causes sudden

oak death). Despite their impact on aquaculture as well as human health, animal pathogenic oomycetes

have been less well studied due to the lack of a tractable model organism. We recently discovered that

the oomycete Myzocytiopsis humicola is a natural pathogen of the model organism Caenorhabditis

elegans. Therefore we aim to study and elucidate the animal-oomycete interactions that occur during

infection using this model. This project seeks to investigate the effectors secreted by oomycetes during

animal infection which counter host defences and result in successful infection.

Putative virulence factors will be predicted from the genomes of nematode-infecting oomycetes using

bioinformatic analyses and their effect on host immunity and physiology will be assessed upon

heterologous expression in C. elegans. Based upon the virulence factors we discover in nematode-

infecting oomycetes, we aim to predict related virulence factors in animal pathogenic oomycetes such as

Pythium insidiosum. Furthermore, we will investigate how the genetic background of a C. elegans strain

and the genetic background of the infecting oomycete interact to determine the susceptibility of worms to

infection.

Insights gained on the pathogenicity of nematicidal oomycetes will be leveraged to develop biocontrol

strategies for plant-parasitic nematodes, utilising any virulence factors identified.