Genetic diversity of Colletotrichum lupini

Lupin cultivation worldwide is threatened by anthracnose, a destructive disease caused by the seed- and air-borne fungal pathogen Colletotrichum lupini. In this study we explored the intraspecific diversity of 39 C. lupini isolates collected from different lupin cultivating regions around the world, and representative isolates were screened for their pathogenicity and virulence on white and Andean lupin. Multi-locus phylogeny and morphological characterizations showed intraspecific diversity to be greater than previously shown, distinguishing a total of six genetic groups and ten distinct morphotypes. Highest diversity was found across South America, indicating it as the center of origin of C. lupini. The isolates that correspond to the current pandemic belong to a genetic and morphological uniform group, were globally widespread, and showed high virulence on tested white and Andean lupin accessions. Isolates belonging to the other five genetic groups were mostly found locally and showed distinct virulence patterns. Two highly virulent strains were shown to overcome resistance of advanced white lupin breeding material.

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Fig: Symptoms on lupin tissue associated with Collletotrichum lupini. (A) typical stem twisting (Lupinus mutabilis); (B) on the leaves (L. albus); (C) on the main stem (L. albus); (D–F) on the pods (L. albus). Photos by Alkemade JA. 

This stresses the need to be careful with international seed transports in order to prevent spread of currently confined but potentially highly virulent strains. This study improves our understanding of the diversity, phylogeography and pathogenicity of a member of one of the world’s top 10 plant pathogen genera, providing valuable information for breeding programs and future disease management.

Alkemade, J.A., Messmer, M.M., Voegele, R.T. et al. Genetic diversity ofColletotrichum lupini and its virulence on white and Andean lupin. Sci Rep 11, 13547 (2021). https://doi.org/10.1038/s41598-021-92953-y

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