P-189 - Phylogenomic and effectorome analysis of Australian clubroot isolates

Clubroot is a major soil-borne plant disease infecting a broad range of brassica crops, leading to significant yield loss internationally. In Australia, clubroot disease is a serious problem in brassica vegetable crops. With the increasing acreage of canola-growing regions, Australia is on its way to facing a serious clubroot problem similar to current outbreaks in Canada. Although the Canadian isolate of the clubroot causal agent, Plasmodiophora brassicae, was recently sequenced, comparative genomic studies remain limited due to the lack of complete genomes from a diverse geographic range. Here we address the lack of genomic and phylogenomic data for Australian clubroot isolates. We have generated the first telomere-to-telomere complete genome assemblies for Australian field-sampled clubroot isolates. We have further sequenced a set of 13 clubroot samples collected across a wide geographic range to build the high-confidence phylogenetic tree, placing the Australian isolates into an international context. Finally, we leveraged genomic data to identify shared small secreted proteins across multiple isolates, constructing the effectorome of the clubroot pathogen. These reference-quality whole genome assemblies, phylogenomic analyses and effectorome predictions are foundational resources for studies on clubroot evolutionary dynamics and the molecular interplay between this pathogen and its host.