A new set of international Leptosphaeria maculans isolates as a resource for elucidation of the basis and evolution of blackleg disease on Brassica napus
Résumé
Abstract A collection of isolates of the fungi Leptosphaeria maculans and L . biglobosa , which cause blackleg disease on Brassica napus (canola/oilseed rape) and other Brassicaceae species, was assembled to represent the global diversity of these pathogens and a resource for international research. The collection consists of 226 isolates (205 L . maculans and 21 L . biglobosa ) from 11 countries. The genomes of all 205 L . maculans isolates were sequenced, and the distribution and identity of avirulence gene alleles were determined based on genotypic information and phenotypic reactions on B . napus lines that hosted specific resistance genes. Whilst the frequencies of some avirulence alleles were consistent across each of the regions, others differed dramatically, potentially reflecting the canola/oilseed rape cultivars grown in those countries. Analyses of the single‐nucleotide polymorphism (SNP) diversity within these L . maculans isolates revealed geographical separation of the populations. This "open access" resource provides a standardized set of isolates that can be used to define the basis for how these fungal pathogens cause disease, and as a tool for discovery of new resistance traits in Brassica species.
