Evolution of virulence in fungal plant pathogens: exploiting fungal genomics to control plant disease.
The propensity of a fungal pathogen to evolve virulence depends on features of its biology (e.g. mode of reproduction) and of its genome (e.g. amount of repetitive DNA). Populations of Leptosphaeria maculans, a pathogen of Brassica napus (canola), can evolve and overcome disease resistance bred into canola within three years of commercial release of a cultivar. Avirulence effector genes are key fungal genes that are complementary to resistance genes. In L. maculans these genes are embedded within inactivated transposable elements in genomic regions where they are readily mutated or deleted. The risk of resistance breakdown in the field can be minimised by monitoring disease severity of canola cultivars and virulence of fungal populations using high throughput molecular assays and by sowing canola cultivars with different resistance genes in subsequent years. This strategy has been exploited to avert yield losses due to blackleg disease in Australia.
School of Botany, the University of Melbourne, VIC 3010, Australia bhowlett@unimelb.edu.au.
Barbara J
BJ
Howlett
School of Botany, University of Melbourne, VIC 3010, Australia.
Rohan G T
RG
Lowe
Marcroft Grains Pathology, Grains Innovation Park, Horsham, VIC 3400, Australia.
Stephen J
SJ
Marcroft
School of Botany, the University of Melbourne, VIC 3010, Australia.
Angela P
AP
van de Wouw
D019143:Evolution, Molecular; D005658:Fungi / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity*; D016681:Genome, Fungal; D023281:Genomics; D010935:Plant Diseases / Q000382:microbiology* / Q000517:prevention & control; D014774:Virulence
Brassica napus; Leptosphaeria maculans; avirulence; effector