Sugarcane leaf scald disease in sugarcane planting areas of Beihai,Guangxi

ObjectiveSugarcane with suspected leaf scald disease in Beihai sugarcane fields in Guangxi were identi-fied by PCR test to determine whether the disease occurs in Beihai,Guangxi,and to provide scientific basis for the con-trol of sugarcane leaf scald.MethodIn November,2016,372 sugarcane samples with suspected leaf scald disease in Hepu County,Yinhai District and Tieshangang District of Beihai,Guangxi were collected,which belonged to 19 varie-ties/lines. PCR test was conducted on DNA of the samples collected using specific primers XAF1 and XAR1 of Xan-thomonas albilineans(Ashby)Dowson(pathogeny of sugarcane leaf scald).PCR products with positive bands were reco-vered and sequenced,than BLAST comparison of the results were conducted in NCBI.ResultIn the 372 samples,there were 78 samples amplified target bands with positive detection rate being 20.97%.Out of 19 sugarcane varieties,13 ones had target band with positive detection rate being 68.42%.The sugarcane varieties with high positive detection rate of sugar-cane leaf scaldwere Liucheng 07-95(75.00%),Guitang 46(68.75%),Guitang 42(48.15%),Liucheng 07-536(33.33%). Partial positive bands were cloned and sequenced,then BLAST comparison of their sequences were conducted in NCBI. The results showed that they had 99% homology with the Guangxi leaf scald disease isolate KY315212.1,which con-firmed that they belonged to leaf scald disease gene fragment sequences.ConclusionSugarcane leaf scald disease occurs in Beihai,Guangxi.Therefore,quarantine must be strengthened and diseased sugarcane cannot be transported from in-fected area to prevent the further spread of the disease.