Telomere-to-telomere genome assembly of the clubroot pathogen Plasmodiophora brassicae

ABSTRACT Plasmodiophora brassicae (Woronin, 1877), a biotrophic, obligate parasite, is the causal agent of clubroot disease in brassicas. The clubroot pathogen has been reported in more than 80 countries worldwide, causing economic losses of hundreds of millions every year. Despite its widespread impact, very little is known about the molecular strategies it employs to induce the characteristic clubs in the roots of susceptible hosts during infection, nor about the mechanisms it uses to overcome genetic resistance. Here, we provide the first telomere-to-telomere complete genome of Plasmodiophora brassicae. We generated ∼ 27 Gb of Illumina, Oxford Nanopore, and PacBio HiFi data from resting spores of strain Pb3A and produced a 25.3 Mb assembly comprising 20 chromosomes, with an N50 of 1.37 Mb. The BUSCO score, the highest reported for any member of the group Rhizaria (Eukaryota: 88.2%), highlights the limitations within the Eukaryota database for members of this lineage. Using available transcriptomic data and protein evidence, we annotated the Pb3A genome, identifying 10,521 protein-coding gene models. This high-quality, complete genome of Plasmodiophora brassicae will serve as a crucial resource for the plant pathology community to advance the much-needed understanding of the evolution of the clubroot pathogen. SIGNIFICANCE Plasmodiophora brassicae (Woronin, 1877) is a devastating plant pathogen, member of the Rhizaria group, and is putting at risk the oilseed rape and cruciferous vegetable industry worldwide. Here, we present the first telomere-to-telomere genome of P. brassicae, and the first complete genome for a member of the Rhizaria taxon. We also provide a high-quality genome annotation featuring an enhanced gene model relative to previous studies. This complete genome will be of great interest to researchers focused on the ecology and evolution of the clubroot pathogen, as well as those studying other members of the Rhizaria group.