Race structure and frequency of avirulence genes in the western Canadian Leptosphaeria maculans pathogen population,the causal agent of blackleg in brassica species          下载免费PDF全文

S. H. Liban  D. J. Cross  H. R. Kutcher  G. Peng  W. G. D. Fernando 《Plant pathology》2016,65(7):1161-1169

Leptosphaeria maculans is the causal agent of blackleg, a serious disease on canola/rapeseed in western Canada, Australia and Europe. Genetic resistance and extended crop rotation provided effective disease control in western Canada for years but the emergence of new pathogen races has reduced the effectiveness of current management strategies. The objective of this study was to analyse L. maculans isolates derived from canola stubble in commercial fields collected in 2010 and 2011 across western Canada for the presence and frequency of avirulence (Avr) genes. A total of 674 isolates were examined for the presence of Avr alleles AvrLm1, AvrLm2, AvrLm3, AvrLm4, AvrLm6, AvrLm7, AvrLm9, AvrLepR1, AvrLepR2 and AvrLmS using a set of differential host genotypes carrying known resistance genes or PCR amplification of AvrLm1, AvrLm6 and AvrLm4–Lm7. Certain alleles were more prevalent in the pathogen population, with AvrLm6 and AvrLm7 present in >85% of isolates, while AvrLm3, AvrLm9 and AvrLepR2 were present in <10% of isolates. A total of 55 races (different combinations of Avr alleles) were detected, with the two most common ones being AvrLm2–Lm4–Lm6–Lm7 and AvrLm2–Lm4–Lm6–Lm7–LmS. Races carrying as many as seven and as few as one known Avr allele were detected. Selection pressure from the race‐specific resistance genes carried in canola cultivars has probably played a significant role in the current Avr profile, which may have also contributed to the recent increase in blackleg observed in western Canada.  相似文献   

Comparing the effectiveness of R genes in a 2-year canola–wheat rotation against Leptosphaeria maculans,the causal agent of blackleg disease in Brassica species     

Rashid  M. Harunur  Liban  Sakaria H.  Zhang  Xuehua  Parks  Paula S.  Borhan  Hossein  Fernando  W. G. Dilantha 《European journal of plant pathology / European Foundation for Plant Pathology》2022,163(3):573-586

European Journal of Plant Pathology - Blackleg, which is caused by the ascomycete fungus Leptosphaeria maculans, is a major disease of canola in Canada and worldwide. In Canada, canola is usually...  相似文献