Duganella phyllosphaerae sp. nov., isolated from the leaf surface of Trifolium repens and proposal to reclassify Duganella violaceinigra into a novel genus as Pseudoduganella violceinigra gen. nov., comb. nov.

A bright yellow pigmented bacterium was isolated from the leaf surface of Trifolium repens in Germany. Comparative analysis of 16S rRNA gene sequences showed that this bacterium is most closely related to Duganella zoogloeoides IAM 12670T, with a similarity of 99.3%, but revealed only a moderate similarity (96.8%) to the second Duganella species, Duganella violaceinigra YIM 31327T. Strain T54T is clearly different from D. zoogloeoides IAM 12670T in that DNA-DNA hybridization revealed a similarity value of 46% (reciprocal 42%). Ubiquinone (Q-8) was the respiratory quinone and the predominant polar lipids consisted of phosphatidylglycerol, phosphatidylethanolamine, three unknown phospholipids and one aminolipid. Strain T54T can be distinguished from D. zoogloeoides by the carbon substrate utilization tests of d-trehalose, cis-aconitate, trans-aconitate, glutarate and dl-3-hydroxybutyrate, and 4-hydroxybenzoate in addition to a different polar lipid profile. The name Duganella phyllosphaerae sp. nov. is proposed for this novel species, with the type strain T54T (=LMG 25995T=CCM 759T). In addition, it is proposed to reclassify D. violaceinigra into a novel genus Pseudoduganella gen. nov. as the novel species Pseudoduganella violaceinigra comb. nov. because of the low 16S rRNA gene sequence similarities to the other Duganella species (<97%) and striking differences in chemotaxonomic (lipid profiles and fatty acid patterns) and other phenotypic features, including the colony pigmentation.