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Title: GENETIC CHARACTERIZATION AND DIVERSITY OF RATHAYIBACTER TOXICUS

Author
item Schaad, Norman
item AGARKOVA, I - UNIVERSITY OF NEBRASKA
item VIDAVER, A - UNIVERSITY OF NEBRASKA
item POSTNIKOVA, E - NATIONAL CANCER INSTITUTE
item RILEY, I - UNIV.ADELAIDE, AUSTRALIA

Submitted to: Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/21/2006
Publication Date: 11/10/2006
Citation: Schaad, N.W., Agarkova, I.V., Vidaver, A.K., Postnikova, E.N., Riley, I.T. 2006. Genetic characterization and diversity of rathayibacter toxicus. Phytopathology. 96:1270-1277

Interpretive Summary: The bacterium Rathayibacter toxicus is responsible for a serious gumming disease and toxin production in several grasses in Australia. Livestock and sheep that consume infected pasture grass suffer a toxicosis characterized by neurological symptoms, often leading to death. Little is known about the molecular characterization of the organism. Using a DNA fingerprinting technique called Amplified fragment length poymorphism (AFLP), we determined the genetic diversity and fingerprinted 22 strains of the bacterium. The strains typed into three genetic clusters that correspond to their geographic origin within Australia. If the pathogen were to be introduced accidentally or deliberately into the USA, the organism and its source could be quickly and easily determined using our method.

Technical Abstract: Twenty-two strains of Rathayibacter toxicus from Australia were characterized using amplified fragment length polymorphism (AFLP) and pulse field gel electrophoresis (PFGE). No plasmids were detected. AFLP analysis grouped the 22 strains into three genetic clusters that correspond to their geographic origin. The mean similarity between the three clusters was 85-86%. PFGE analysis generated three different banding patterns that enabled typing the strains into three genotypic groups corresponding to the same AFLP clusters. The similarity coefficient was 63-81% for XbaI and 79-84% for SpeI. AFLP and PFGE analyses exhibited an analogous level of discriminatory power and produced congruent results. PFGE analysis indicated that the R. toxicus genome was represented by a single linear chromosome, estimated to be 2.214-2.301 Mbp.