Devosia lacusdianchii sp. nov., an attached bacterium inhibited by metabolites from its symbiotic Microcystis.

A novel alphaproteobacterial strain JXJ CY 41T was isolated from a culture mass of Microcystis, collected from Lake Dianchi, south-west, China. Strain JXJ CY 41T was gram-strain-negative, aerobic, motile, with rod-shaped cells (0.4-1.0 × 1.7-3.5 µm). It was positive for catalase and starch hydrolysis, negative for oxidase and hydrolysis of Tweens (20, 40, and 80). Growth occurred at 10-44 °C, pH 5.0-10.0, and 0-5.0% (w/v) NaCl. Major fatty acids included C16:0 (28.1%), 11-methyl C18:1 ω7c (36.7%) and C18:1 ω7c (20.8%). Q10 was the sole ubiquinone. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, glycolipid, and an unidentified lipid. The DNA G + C content was 63.1%. Its 16S rRNA gene sequence showed high similarities with Devosia oryziradicis G19T (99.5%; not validly published), D. yakushimensis Yak96BT (98.3%) and D. ginsengisoli Gsoil 520T (98.1%), and less than 98.1% similarities with other members of the genus Devosia. The digital DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) values between strain JXJ CY 41T and its 5 closest similar strains were 19.9-24.1% and 75.7-80.5%, respectively. Based on the data above, strain JXJ CY 41T was identified as a novel species of the genus Devosia, for which the epithet Devosia lacusdianchii sp. nov. was proposed. The type strain is JXJ CY 41T (= KCTC 72812T = CGMCC 1.17502T). Strain JXJ CY 41T exhibited different interactions with Microcystis aeruginosa FACHB-905 (Maf) under different conditions, and Maf could control the bacterial cellular density by secreting unknown specific chemical compounds according to its nutritional requirements.

Microbacterium lacusdiani sp. nov., a phosphate-solubilizing novel actinobacterium isolated from mucilaginous sheath of Microcystis.

A novel actinobacterium, designated strain JXJ CY 01T, was isolated from a mucilaginous sheath of Microcystis aeruginosa FACHB-905 collected from Lake Dianchi, south-west China. Taxonomic position of the isolate was determined by polyphasic approaches. Strain JXJ CY 01T shared 16S rRNA sequence similarities of 98.9 and 98.0% with Microbacterium marinilacus YM11-607T and Microbacterium paludicola US15T, and less than 98% with other members of the genus Microbacterium. The DNA-DNA relatedness values between strains JXJ CY 01T and M. marinilacus JCM 16546T and M. paludicola JCM 14308T were 53.5±1.4 and 53.8±2.1%, respectively. l-Ornithine was detected in the cell wall, and rhamnose, galactose, glucose, arabinose, fucose and mannose as signature sugars in the whole-cell hydrolysates. Other chemotaxonomic characteristics determined were MK-12 and MK-11 as predominant menaquinones, anteiso-C15:0, iso-C16:0, anteiso-C17:0 and iso-C17:0 as major cellular fatty acids (>10%), and diphosphatidylglycerol, phosphatidylglycerol, an unidentified glycolipid and two unidentified phospholipids as the polar lipids. The DNA G+C content was 70.4 mol%. On the basis of the above taxonomic data, strain JXJ CY 01T is determined to represent a novel species of the genus Microbacterium, for which the name Microbacterium lacusdiani sp. nov. is proposed. The type strain is JXJ CY 01T (= KCTC 29655T=DSM 29188T). The type strain JXJ CY 01T can solubilize both insoluble inorganic (calcium phosphate) and organic phosphate (l-α-phosphatidylcholine) and is possibly one of the mechanism for enhancement of growth of M. aeruginosa FACHB-905.