Genetic diversity of Colletotrichum lupini and its virulence on white lupin (Lupinus albus)

Summary

White lupin (Lupinus albus) is a grain legume known for its high protein content and quality, efficient nutrient acquisition and health benefits 1, 2. Its high yield potential could make it a sustainable alternative to soybean in cooler regions 3. However, since the 1980s anthracnose disease, caused by the air- and seed-borne fungal disease Colletotrichum lupini, threatens lupin cultivations worldwide 4-6. Even low levels of seed infestation can lead up to total yield loss7, 8. To assist white lupin breeding programs, we analyzed the genetic diversity of globally collected lupin-infecting Colletotrichum isolates by multi-locus sequencing 9, 10. First analyses indicate that all isolates belong to the species C. lupini and that the genetic diversity of isolates collected from Europe and Australia is lower compared with isolates collected from South America. An indoor screening assay was developed and validated by field performance, allowing to determine differences in virulence between C. lupini strains under controlled conditions. Currently, virulence tests of selected C. lupini isolates are being performed on two white lupin cultivars, the susceptible variety Feodora and the tolerant breeding line Blu-25 from Erik von Baer. Our study will shed light on the genetic makeup of the species C. lupini and its relation to virulence on white lupin, thereby providing valuable information to improve white lupin breeding programs.