Submitted to: Systematic and Applied Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 2, 2010
Publication Date: February 1, 2010
Citation: Bull, C.T., Lesaux, M., Manceau, C., Lydon, J., Kong, H.N., Vinatzer, B.A. 2010. Pseudomonas cannabina pv.cannabina pv. nov., and Pseudomonas cannabina pv. alisalensis(Cintas Koike and Bull 2000)comb. nov., are members of the emended species Pseudomonas cannabina(ex Šutic & Dowson 1959)Gardan et al., 1999. Systematic and Applied Microbiology. doi:10.1016/j.syapm.2010.02.001. Interpretive Summary: The control of bacterial plant pathogens is fundamental to providing high quality food and fiber to consumers. Disease control and prevention is dependant upon understanding what organisms are causing the diseases. This manuscript describes similarities between two pathogens that cause disease of crucifers such as broccoli, cauliflower, rutabega, arugula and broccoli raab and their relationship to a pathogen of hemp. The work demonstrated that the hemp pathogen and one of the crucifer pathogens are the same species although they cause disease on a different crop plants. Additionally, the manuscript provides descriptions of characters that can be used to distinguish between the two crucifer pathogens. These data are useful in rapid identification of these and similar pathogens and to design disease control strategies.
Technical Abstract: Phenotypic data suggested that the crucifer pathogen Pseudomonas syringae pv. alisalensis belongs to P. syringae sensu lato and this was confirmed by sequence similarity in the 16S rDNA gene demonstrated in this research. Labeled DNA from P. syringae pv. alisalensis was used as a probe in DNA/DNA hybridization experiments against representatives from the 8 previously delineated genomospecies into which pathovars of P. syringae have been assigned. DNA-relatedness was low (below 43%) between P. syringae pv. alisalensis and the reference strain from genomospecies 3 (P. syringae pv. tomato) although the well-known crucifer pathogen, P. syringae pv. maculicola, also belongs to genomospecies 3. In contrast a high degree of DNA-relatedness, 69-100%, was shown between P. syringae pv. alisalensis strains and the type strain of P. cannabina (genomospecies 9) in reciprocal hybridizations. For six additional genomospecies, DNA-DNA hybridization levels were below 48%. Additional evidence that P. syringae pv. alisalensis belongs to P. cannabina was the sequence identity or similarity in seven gene fragments used in Multilocus Sequence Typing (MLST), as well as similar rep-PCR patterns when using the BOX-A1R primers. Because the strains previously designated as P. syringae pv. alisalensis differ phenotypically from P. cannabina, the description of P. cannabina has been emended to include these strains. Host range testing demonstrated that P. syringae pv. alisalensis strains, originally isolated from broccoli, broccoli raab or arugula, were not pathogenic on Cannabis sativa (family Cannabinaceae). Additionally, P. cannabina strains, originally isolated from the C. sativa were not pathogenic on broccoli raab or oat while P. syringae pv. alisalensis strains were pathogenic on these hosts. Distinct host ranges for these two groups indicate that P. cannabina emend. consists of at least two distinct pathovars, P. cannabina pv. cannabina pv. nov., and P. cannabina pv. alisalensis comb. nov.. Pseudomonas syringae pv. maculicola strain CFBP 1637 is a member of P. cannabina.