Microbe-Host Interactions

We’re exploring how a deeper understanding of pathogen–host interactions could generate new tools, technologies, and approaches for protecting whole ecosystems from disease. This project builds, in part, on the National Science Project (Ngā Rākau Taketake), which generated a high-quality genome sequence and chromosome-level assembly for the kauri dieback pathogen Phytophthora agathidicida.

From this new genome sequence, we’re creating gene models that will be evaluated to determine their potential roles in kauri dieback. The discovery that Phytophthora agathidicida can complete its life cycle in the model plant Nicotiana benthamiana provides an excellent pathosystem for this evaluation. We’re also planning a proteomics experiment to identify the proteins secreted into the apoplast by both the pathogen and the host.

This project also focuses on Phytophthora cinnamomi, a broad-ranging pathogen often found in kauri forests. The first stage of this work is to assess the genetic diversity of isolates collected from different hosts.

To do this, we’ve obtained a set of isolates from the Scion collection, confirmed their identity, and are now preparing DNA for genome sequencing. Proteomics analysis of this species in Nicotiana benthamiana will follow, enabling comparative studies with Phytophthora agathidicida.

We’re learning how fundamental research can lead to new approaches for managing pests and pathogens. By focusing on effector proteins from the broad host-range pathogen Phytophthora cinnamomi and the kauri dieback pathogen Phytophthora agathidicida, researchers are uncovering how these effectors interact with each other — and how those interactions may influence disease outcomes in forest ecosystems.

The findings show that Phytophthora effectors can trigger immune or defence responses in host plants, slowing infection. But not all hosts respond the same way. Gymnosperms and angiosperms show different defence patterns, offering important clues about how to tailor bioprotection strategies.