Evolution of Linked Avirulence Effectors in Leptosphaeria maculans Is Affected by Genomic Environment and Exposure to Resistance Genes in Host Plants
MetadataShow full item record
©2010 Van de Wouw et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Brassica napus (canola) cultivars and isolates of the blackleg fungus, Leptosphaeria maculans interact in a ‘gene for gene’ manner whereby plant resistance (R) genes are complementary to pathogen avirulence (Avr) genes. Avirulence genes encode proteins that belong to a class of pathogen molecules known as effectors, which includes small secreted proteins that play a role in disease. In Australia in 2003 canola cultivars with the Rlm1 resistance gene suffered a breakdown of disease resistance, resulting in severe yield losses. This was associated with a large increase in the frequency of virulence alleles of the complementary avirulence gene, AvrLm1, in fungal populations. Surprisingly, the frequency of virulence alleles of AvrLm6 (complementary to Rlm6) also increased dramatically, even though the cultivars did not contain Rlm6. In the L. maculans genome, AvrLm1 and AvrLm6 are linked along with five other genes in a region interspersed with transposable elements that have been degenerated by Repeat-Induced Point (RIP) mutations. Analyses of 295 Australian isolates showed deletions, RIP mutations and/or non-RIP derived amino acid substitutions in the predicted proteins encoded by these seven genes. The degree of RIP mutations within single copy sequences in this region was proportional to their proximity to the degenerated transposable elements. The RIP alleles were monophyletic and were present only in isolates collected after resistance conferred by Rlm1 broke down, whereas deletion alleles belonged to several polyphyletic lineages and were present before and after the resistance breakdown. Thus, genomic environment and exposure to resistance genes in B. napus has affected the evolution of these linked avirulence genes in L. maculans.
Showing items related by title, author, creator and subject.
Allelic barley MLA immune receptors recognize sequence-unrelated avirulence effectors of the powdery mildew pathogenLu, X.; Kracher, B.; Saur, I.; Bauer, S.; Ellwood, Simon; Wise, R.; Yaeno, T.; Maekawa, T.; Schulze-Lefert, P. (2016)© 2016, National Academy of Sciences. All rights reserved. Disease-resistance genes encoding intracellular nucleotide-binding domain and leucine-rich repeat proteins (NLRs) are key components of the plant innate immune ...
Comparative analysis of the predicted secretomes of Rosaceae scab pathogens Venturia inaequalis and V. pirina reveals expanded effector families and putative determinants of host rangeDeng, C.; Plummer, K.; Jones, Darcy; Mesarich, C.; Shiller, J.; Taranto, A.; Robinson, A.; Kastner, P.; Hall, N.; Templeton, M.; Bowen, J. (2017)© 2017 The New Zealand Institute for Plant and Food Research Limited. Background: Fungal plant pathogens belonging to the genus Venturia cause damaging scab diseases of members of the Rosaceae. In terms of economic impact, ...
The Nuclear Immune Receptor RPS4 Is Required for RRS1(SLH1)-Dependent Constitutive Defense Activation in Arabidopsis thalianaSohn, K.; Segonzac, C.; Rallapalli, G.; Sarris, P.; Woo, J.; Williams, S.; Newman, Toby; Paek, K.; Kobe, B.; Jones, J. (2014)Plant nucleotide-binding leucine-rich repeat (NB-LRR) disease resistance (R) proteins recognize specific “avirulent” pathogen effectors and activate immune responses. NB-LRR proteins structurally and functionally resemble ...