Identifing Pathogeny Of Bacteroidal Leaf Spot Disease In The Yam

Leaf spot disease is the new disease found in the yam. There is no report about studing it. The disease is confirmed bacteroidal disease preliminarily in our study, according to the disease state of yam and the experiment of microscope checking.Fourbacterium(YLS-1,YLS-2,YLS-3,YLS-4) which had different cultivate character were isolated from the leaf of susceptible yam and infected yam back under the fitting circumstance. Only strain YLS-2 can cause disease, and the disease symptom was consistant with the former diseased leaf. Cultivated bacterium isolated from diseased yam was consistant with the foregone, the results accord with Koch's Postulate. The isolated matter(YLS-2) from bacterium was tested be a pathogeny of leaf spot disease in the yam.Three standard strain were used in the experiments of observing morphology andphysiology and biochemistry, such as 2584(Curtobacterium flaccumfaciens pv. Flaccumfaciens),T30(Cur. f'. pv. Beticila)and ICMP3023(Pseudomonas syringae pv. Syringae). YLS-2,T30 and 2584 were tested be most similar, may be they are similary strip.The full sequences of YLS-2 genome was taken as the template for PCR amplifying using current 16SrDNA primer. About1500bp special band was recovered, cloned and sequenced, the 1485bp band was got. This sequence was submitted to genebank and search its homologous sequence by blast. In the former 39 sequences which has near relative, the former 35 sequences belong to Curtobacterium. Using DNA star soft to analyze, both leaf spot disease strain and Curtobacterium flaccumfaciens pv. basellae (logging code: AY273210) singly belong to the same branch according to the phylogenetic tree, and their homology reach to 98.7 %. The results showed leaf spot disease of yam bacterium is a great probability of the mution.causing disease of Cur.flaccumfaciens.Current ITS primer was used to amplify the full sequences of YLS-2 genome. The special band was recovered,cloned and sequenced, and we got the 501bp band. This ITS sequence was submitted to genebank and search its homologous sequence by...