Genetic diversity of Sclerotinia sclerotiorum isolates by SSR markers

Genetic variability of the 30 isolates from Europe and China was analyzed using SSR markers.Isolates were amplified by three microsatellite primer pairs,which generated a total of 21 polymorphic bands ranging from 158 bp to 358 bp in size,and an average of 7 bands per primer pair.Genetic relationship among isolates was investigated based on the result of SSR markers.Genetic similarity of 30 isolates was rather high.At species level,Nei's genetic diversity was 0.139 3,and Shannon's index of diversity was 0.248 8.Nei's genetic distance of different populations(from 0.009 6 to 0.049 6) was very short,and the genetic distance between Russia and the Austria + the United Kingdom populations was long.From the cluster results,the clusters based on SSR markers showed no clear relationship with geographical origin of the studied isolates.The third cluster was the most distant and from China only,suggesting that the genetic distance for the Chinese isolates of the third cluster was further than the isolates from the other two clusters.At species level,the gene flow was high(2.111 6) although coefficient of gene differentiation value was low(0.191 5).