Curtobacterium ammoniigenes sp. nov., an ammonia-producing bacterium isolated from plants inhabiting acidic swamps in actual acid sulfate soil areas of Vietnam

Abstract

The ammonia-producing bacteria B55T, CA73, SA69 and SA72 were isolated from the waterweeds Ludwigia adscendens (B55T) and Eleocharis dulcis (CA73, SA69 and SA72) grown in highly acidic swamps (pH 2–4) in actual acid sulfate soil areas of Vietnam. The isolates were Gram-positive, irregular rod-shaped, non-spore-forming bacteria. On the basis of 16S rRNA gene sequence similarity, strain B55T was shown to belong to the genus Curtobacterium of the class Actinobacteria. Chemotaxonomic data (MK-9 as major isoprenoid quinone, d-ornithine as cell-wall diamino acid, acetyl as the acyl type of peptidoglycan) supported the affiliation of all four strains to this genus. Although their 16S rRNA gene sequence similarity was 99 % to species with validly published names within the genus, they formed a group that was distinct in the phylogenetic tree, and DNA–DNA relatedness values to these established species were less than 10 %. The results of physiological and biochemical tests and major fatty acids (cyclohexyl-C17 : 0, anteiso-C17 : 0 and cyclohexyl-C19 : 0) allowed phenotypic differentiation of these strains from the species of Curtobacterium with validly published names. Therefore, strains B55T, CA73, SA69 and SA72 represent a novel species, for which the name Curtobacterium ammoniigenes sp. nov. is proposed. The type strain is B55T (=NBRC 101786T=VTCC D6-11T=JCM 14609T).