Haliangium ochraceum gen. nov., sp. nov. and Haliangium tepidum sp. nov.: Novel moderately halophilic myxobacteria isolated from coastal saline environments.

Abstract

Phenotypic and phylogenetic studies were performed on two myxobacterial strains, SMP-2 and SMP-10, isolated from coastal regions. The two strains are morphologically similar, in that both produce yellow fruiting bodies, comprising several sessile sporangioles in dense packs. They are differentiated from known terrestrial myxobacteria on the basis of salt requirements (2-3% NaCl) and the presence of anteiso-branched fatty acids. Comparative 16S rRNA gene sequencing studies revealed that SMP-2 and SMP-10 are genetically related, and constitute a new cluster within the myxobacteria group, together with the Polyangium vitellinum Pl vt1 strain as the closest neighbor. The sequence similarity between the two strains is 95.6%. Based on phenotypic and phylogenetic evidence, it is proposed that these two strains be assigned to a new genus, Haliangium gen. nov., with SMP-2 designated as Haliangium ochraceum sp. nov. (= JCM 11303(T) = DSM 14365(T)), and SMP-10 as Haliangium tepidum sp. nov. (= JCM 11304(T)= DSM 14436(T)).