Oryzomicrobium terrae gen. nov., sp. nov., of the family Rhodocyclaceae isolated from paddy soil.

Abstract

A polyphasic approach was used to characterize a novel bacterium, designated strain TPP412T, isolated from a paddy soil in Taiwan. Strain TPP412T was Gram-stain-negative, facultatively anaerobic, rod-shaped, motile with a single polar flagellum and lacked bacteriochlorophyll. Growth was observed at 24-45 °C (optimal 25 °C), at pH 5.0-10.0 (optimal pH 7.0) and with 0-0.75 % (w/v) NaCl. Strain TPP412T showed highest 16S rRNA gene sequence similarity to members of the genera Rhodocyclus (94.1-94.5 %), Azospira (93.9-94.5 %) and Propionivibrio (93.4-94.4 %) and established a discrete taxonomic lineage in phylogenetic analysis. The major fatty acids found in strain TPP412T were C12 : 0, C12 : 0 3-OH, iso-C15 : 0 3-OH, C16 : 0, C16 : 1ω7c/C16 : 1ω6c and C18 : 1ω7c/C18 : 1ω6c. The major polar lipids consisted of phosphatidylmonomethylethanolamine, diphosphatidylglycerol, phosphatidylglycerol and an unidentified lipid. The polyamine pattern showed a predominance of putrescine and a minor amount of spermidine. The DNA G+C content was 58.4 mol% and the predominant quinone system was ubiquinone-8 (Q-8). The low 16S rRNA gene sequence similarity values (≤94.5%) and distinct phylogenetic clustering clearly distinguished strain TPP412T from other representatives of the family Rhodocyclaceae. Based on the discrete phylogenetic, phenotypic and chemotaxonomic traits together with results of comparative 16S rRNA gene sequence analysis, strain TPP412T is considered to represent a novel species of a new genus in the family Rhodocyclaceae, for which the name Oryzomicrobium terrae gen. nov., sp. nov. is proposed. The type strain of Oryzomicrobium terrae is TPP412T (=BCRC 80905T=JCM 30814T).