AvrLm4-7 is found in Leptosphaeria maculans, an ascomycete fungus in the dothideomycete group which is responsible for stem canker (blackleg) of Brassica napus (oilseed rape, OSR) and other crucifers. AvrLm4-7 is one of six avirulence genes which enc ...
AvrLm4-7 is found in Leptosphaeria maculans, an ascomycete fungus in the dothideomycete group which is responsible for stem canker (blackleg) of Brassica napus (oilseed rape, OSR) and other crucifers. AvrLm4-7 is one of six avirulence genes which encodes a small secreted protein strongly over-expressed at the onset of plant infection. This gene confers a dual recognition specificity by two distinct resistance genes of OSR, Rlm4 and Rlm7 and loss of AvrLm4 avirulence was demonstrated to be associated with a strong fitness cost. Structure and functional analysis of AvrLm4-7 protein show that it contains the motifs RAWG and RYRE, part of a well-structured protein region held together by disulfide bridges. Mutations in the RAWG motif or in the RYRE motif (especially mutations in both motifs) almost abolished the translocation of AvrLm4-7 into cells. Furthermore, loss of recognition of AvrLm4-7 by Rlm4 is caused by the mutation of a single glycine to an arginine residue located in a loop of the protein [1].
