Pathogen Identification and Phylogenetic Analysis of Sugarcane Rust in Plateau Areas at Low Latitudes

[Objectives]This study was conducted to clarify the species,occurrence and distribution characteristics of sugarcane rust pathogens in low-latitude plateau sugarcane rust areas of Yunnan Province and the phylogenetic relationship between the pathogens and that between them and other rust fungi of the genus Puccinia.[Methods]Fifty seven sugarcane rust samples collected from the sugarcane areas of Baoshan,Lincang,Menghai,Menglian,Ximeng,Lancang and Wenshan in Yunnan were subjected to molecular identification.[Results]The four sugarcane rust samples from Haiyin1 hao in Menghai,Yunnan Province belonged to orange rust of sugarcane,and the pathogen was Puccinia kuehnii Butler.;and other 53 samples of sugarcane rust belonged to brown rust of sugarcane,and the pathogen was Puccinia melanocephala Syd.et P.Syd.The rDNA sequences of other rust fungi from the genus Puccinia were downloaded from GenBank and used for the construction of an NJ tree for systematic evolution analysis together with the sequences obtained in this study.The results showed that the four P.kuehnii sequences obtained in this study were clustered with Puccinia polysora(GenBank accession number:GU058024)into one group,and they were close genetically;the 53 P.melanocephala sequences were clustered with P.nakanishikii(GenBank accession number:GU058002),P.rufipes(GenBank accession number:AJ296545),Aecidium deutziae(GenBank accession number:KU309317)and P.coronata(GenBank accession number:DQ354526)into one group,and they had a close genetic relationship;and the genetic relationship of the two species of sugarcane rust fungi identified in this study was relatively distant.[Conclusions]This study provides a scientific basis for sugarcane rust epidemic prediction,disease resistance breeding,and precise prevention and control.

The Quarantine Disease Sugarcane Leaf Scald Found in Xinping Sugarcane Area in Yunnan Province

[Objectives]This study was conducted to clarify the pathogens causing suspected sugarcane leaf scald symptoms in sugarcane plants found in the Xinping sugarcane area of Yunnan in 2019.[Methods]The XAF1/XAR1 specific primers of Xanthomonas albilineans were used to detect 8 suspected samples from Xinping County,Yunnan Province.[Results]The specific band 600 bp in size was detected.The sequencing results showed that the sequences detected were all 608 bp,and were 100%identical.The BLAST search results showed that the obtained sequence was 100%identical to the nucleotide sequence of X.albilineans GPE PC73 strain(GenBank accession number:FP565176)from France,and they were located in the same branch of the phylogenetic tree.According to the field symptom diagnosis and molecular identification results,the sugarcane disease in Xinping,Yunnan was confirmed to be the quarantine disease sugarcane leaf scald caused by X.allbilineasn.[Conclusions]The pathogens were identified by molecular biological identification methods,providing a scientific basis for the prevention and control of leaf scald disease in the future.