Flavobacterium psychrotrophum sp. nov. and Flavobacterium panacagri sp. nov., Isolated from Freshwater and Soil.

Abstract

Two novel bacterial strains CJ74^T and CJ75^T belonging to the genus Flavobacterium were isolated from freshwater of Han River and ginseng soil, South Korea, respectively. Strain CJ74^T was Gram-stain-negative, aerobic, rod-shaped, non-motile, and non-flagellated, and did not produce flexirubin-type pigments. Strain CJ75^T was Gram-stain-negative, aerobic, rod-shaped, motile by gliding, and non-flagellated, and produced flexirubin-type pigments. Both strains were shown to grow optimally at 30 °C in the absence of NaCl on R2A medium. Phylogenetic analysis based on 16S rRNA gene sequences showed that strains CJ74^T and CJ75^T belonged to the genus Flavobacterium and were most closely related to Flavobacterium niveum TAPW14^T and Flavobacterium foetidum CJ42^T with 96.17% and 97.29% 16S rRNA sequence similarities, respectively. Genomic analyses including the reconstruction of phylogenomic tree, average nucleotide identity, and digital DNA-DNA hybridization suggested that they were novel species of the genus Flavobacterium. Both strains contained menaquinone 6 (MK-6) as the primary respiratory quinone and phosphatidylethanolamine as a major polar lipid. The predominant fatty acids of both strains were iso-C_15:0 and summed feature 3 (C_16:1 ω7c and/or C_16:1 ω6c). Based on the polyphasic taxonomic study, strains CJ74^T and CJ75^T represent novel species of the genus Flavobacterium, for which names Flavobacterium psychrotrophum sp. nov. and Flavobacterium panacagri sp. nov. are proposed, respectively. The type strains are CJ74^T (=KACC 19819^T =JCM 32889^T) and CJ75^T (=KACC 23149^T =JCM 36132^T).