P-206 - Profiling the Phytophthora kernoviae secretome during infection of European beech

Trees provide essential crop and ecosystem services such as food, carbon capture, and erosion control. However, as long-lived organisms, they face persistent threats from pests and pathogens. Phytophthora, meaning “plant destroyer,” is a group of eukaryotic microorganisms and is among the greatest disease threats to trees. In the UK and Europe, European beech (Fagus sylvatica) forests are vulnerable to Phytophthora species, notably sudden oak death pathogen P. ramorum, P. kernoviae, P. plurivora, and more. The aim of this project is to characterise the infection mechanisms Phytophthora species use to colonise beech trees. Here, a fluorescently labelled strain of P. kernoviae was imaged in beech stem tissue using a confocal microscope, and pathogen volume was estimated using a machine learning pixel classification method. It was hypothesised that infected stems would contain many cellulose and hemicellulose degrading enzymes, and putative lignin-modifying enzymes such as peroxidases. Vascular fluid was extracted from infected samples and analysed by mass spectrometry, which identified over 100 proteins secreted by P. kernoviae during infection. This work will shed light on how P. kernoviae and other Phytophthora species colonise their woody hosts, and whether this differs from what is known about infections in herbaceous plants.