Leptosphaeria maculans is a serious concern for canola production worldwide.For effective disease management,knowledge of the pathogen’s genetic variability and population structure is a prerequisite.In this study,wh...Leptosphaeria maculans is a serious concern for canola production worldwide.For effective disease management,knowledge of the pathogen’s genetic variability and population structure is a prerequisite.In this study,whole-genome sequencing was performed for 162 of 1590 L.maculans isolates collected in the years 2007e2008 and 2012e2014 in Western Canada.DNA variants in genome-wide and specific regions including avirulence(Avr)genes were characterized.A total of 31,870 high-quality polymorphic DNA variants were used to study L.maculans genetic diversity and population structure.Cluster analysis showed that 150 isolates were clustered into 2 main groups and 4 subgroups by DNA variants located in either Avr or small secreted protein-encoding genes and into 2 main groups and 6 subgroups by genome-wide variants.The analysis of nucleotide diversity and differentiation also confirmed genetic variation within a population and among populations.Principal component analysis with genome-wide variants showed that the isolates collected in 2012e2014 were more genetically diverse than those collected in 2007e2008.Population structure analysis discovered three distinct sub-populations.Although isolates from Saskatchewan and Alberta were of similar genetic composition,Manitoba isolates were highly diverse.Genome-wide association study detected DNA variants in genes AvrLm4-7,Lema_T86300,and Lema_T86310 associated with the years of collection.展开更多
文摘Leptosphaeria maculans is a serious concern for canola production worldwide.For effective disease management,knowledge of the pathogen’s genetic variability and population structure is a prerequisite.In this study,whole-genome sequencing was performed for 162 of 1590 L.maculans isolates collected in the years 2007e2008 and 2012e2014 in Western Canada.DNA variants in genome-wide and specific regions including avirulence(Avr)genes were characterized.A total of 31,870 high-quality polymorphic DNA variants were used to study L.maculans genetic diversity and population structure.Cluster analysis showed that 150 isolates were clustered into 2 main groups and 4 subgroups by DNA variants located in either Avr or small secreted protein-encoding genes and into 2 main groups and 6 subgroups by genome-wide variants.The analysis of nucleotide diversity and differentiation also confirmed genetic variation within a population and among populations.Principal component analysis with genome-wide variants showed that the isolates collected in 2012e2014 were more genetically diverse than those collected in 2007e2008.Population structure analysis discovered three distinct sub-populations.Although isolates from Saskatchewan and Alberta were of similar genetic composition,Manitoba isolates were highly diverse.Genome-wide association study detected DNA variants in genes AvrLm4-7,Lema_T86300,and Lema_T86310 associated with the years of collection.
