Rhodovastum atsumiense gen. nov., sp. nov., a phototrophic alphaproteobacterium isolated from paddy soil

Abstract

A photoorganotrophic alphaproteobacterium designated strain G2-11T was isolated from submerged paddy soil. This bacterium had relatively large, oval to rod-shaped cells (2.0-3.0×3.0-10 μm). Cells were motile by means of single polar flagella. The color of phototrophically growing cultures was reddish-brown. The cell extract had absorption maxima at 375, 465, 492, 529, 592, 804, and 844 nm, Indicating the presence of bacterioghlorophyll a and carotenoides of the spirilloxanthin series. Vesicular intracytoplasmic membranes were present. The main component of cellular fatty acids was C18:1 ω7c. Ubiquinone-10 and rhodoquinone-10 were the major quinones. A 16S rRNA gene sequence analysis revealed that the isolate is closest to the acidophilic aerobic photosynthetic bacterium Acidisphaera rubrifaciens strain HS-AP3T (93.3% similarity). The G+C content of genomic DNA is 67.8 mol%. The name Rhodovastum atsumiense gen. nov., sp. nov. is proposed for the novel isolate. The type strain is strain G2-11T (=NBRC 104268T=KCTC 5708T).