PHENOTYPIC DIVERSITY OF PSEUDOALTEROMONAS-CITREA FROM DIFFERENT MARINE HABITATS AND EMENDATION OF THE DESCRIPTION

Four strains of marine, aerobic, agar-decomposing bacteria with one po lar flagellum and with DNA G+C contents of 38.9-40.2 mol% were isolate d from the Far-Eastern mussels Crenomytilus grayanus and Patinopecten yessoensis. These four strains were identified as Pseudoalteromonas; h owever, they were phenotypically different from species described prev iously according to carbon compound utilization tests and the BIOLOG i dentification system. High alpha-gara-decomposing activity was found i n two strains, in one of which agarase, alpha-galactosidase, pustulana se and laminarinase had been detected. The level of DNA homology of th ree of the strains was 70-100 %. The fourth isolate was genetically le ss related to the others (67 % DNA relatedness) and phenotypically was more distant from other members of this group; however, all four stra ins were assigned to a single species genotypically. DNA from the stra ins isolated from mussels showed 40-45 % genetic relatedness with the DNA of Alteromonas atlantica, 8-36 % with DNA of Pseudoalteromonas hal oplanktis subsp, haloplanktis, Pseudoalteromonas haloplanktis subsp. t etraodonis, Pseudoalteromonas undina, Pseudoalteromonas nigrifaciens a nd Pseudoalteromonas carrageenovora, 53% with Pseudoalteromonas elyako vii, 32-48 % with marine P. nigrifaciens from mussels and 14-16 % with Alteromonas macleodii. The DNA-DNA hybridization data revealed that t he levels of relatedness between the strains isolated and the type str ains of Pseudoalteromonas citrea and Pseudoalteromonas fuliginea descr ibed recently were significant (95-85 %). These results were confirmed by serological data employing polyclonal antibodies to cell surface a ntigens. The strains isolated from mussels were identified as P. citre a. The hybridization data showed that the name P. fuliginea Romanenko et al. 1994 should be recognized as a junior subjective synonym of P. citrea Gauthier 1977. A notable phenotypic diversity of P. citrea whic h might be a reflection of their ecological habitats is discussed.