Leptosphaeria maculans is the fungus responsible for the stem canker disease of oilseed rape ( Brassica napus ). AvrLm3 and AvrLm4‐7 , two avirulence effector genes of L. maculans , are involved in an unusual relationship: AvrLm4‐7 suppresses the Rlm3 ‐mediated resistance. Here, we assessed AvrLm3 polymorphism in a collection of 235 L. maculans isolates. No field isolates exhibited deletion or inactivating mutations in AvrLm3...

Pathogen introductions into novel areas can lead to the emergence of new fungal diseases of plants. Understanding the origin, introduction pathways, possible changes in reproductive system and population size of fungal pathogens is essential in devising an integrated strategy for the control of these diseases. We used minisatellite markers to infer the worldwide invasion history of the fungal plant pathogen Leptosphaeria macul...