|De Silva, A|
Submitted to: Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/27/2003
Publication Date: 9/1/2003
Citation: Yu, Q., Alvarez, M., Moore, P.H., Zee, F.T., Kim, M.S., De Silva, A., Hepperly, P.R., Ming, R. 2003. Molecular diversity of Ralstonia solanacearum ginger strains. Phytopathology 93: 1124-1130. 2003. Interpretive Summary: Ralstonia solanacearum is a complex and heterogeneous species of soil borne plant pathogenic bacteria causing wilt diseases that includes diverse strains differing in genotype, phenotypic properties, and pathogenic potential on potato, tomato, and ginger root. The ability to distinguish among isolates of this pathogen species would facilitate their evaluation as pathotypes that might differ in aggressiveness and methodology for control on different plant species and cultivars. A collaborative project among scientists of ARS, University of Hawaii, and the Hawaii Agricultural Research Center showed that the DNA of races of Ralstonia collected in Hawaii differed among isolates from heliconia, tomato, and ginger root. The ability to fingerprint isolates and determine the phylogenetic relationship among them allows for definitive pathology evaluations not previously possible.
Technical Abstract: The genetic diversity of Ralstonia solanacearum strains isolated from ginger (Zingiber officinale Roscoe) growing on the island of Hawaii was determined by analysis of amplified fragment length polymorphisms (AFLPs). Initially 28 strains of R. solanacearum collected from five host plant species worldwide were analyzed by AFLP. A second analysis was conducted on 55 R. solanacearum strains collected from three ginger farms along the Hamakua Coast of the island of Hawaii, the principle area of ginger cultivation in the state. From the initial analysis R. solanacearum strains from ginger in Hawaii showed a high degree of similarity at 0.853. In contrast, the average genetic similarity between R. solanacearum from heliconia and ginger was only 0.165, and strains from ginger showed little similarity with strains from all other hosts. The second analysis of 55 strains from ginger on different Hawaiian farms confirmed that they were distinct from race 1 strains from tomato. Strains from ginger also showed greater diversity among themselves in the second analysis, and the greatest diversity occurred among strains from a farm where ginger is frequently imported and maintained. Our results provide evidence that R. solanacearum strains from ginger in Hawaii are genetically distinct from local strains from tomato (race 1) and heliconia (race 2).