Flavobacterium movens sp. nov. and Flavobacterium mesophilum sp. nov., two novel bacteria isolated from rhizosphere soil of Litchi (Litchi chinensis Sonn.).

Abstract

Two aerobic, Gram-stain-negative, gliding motility and rod-shaped bacterial strains, designated as B11^T and D4^T, were isolated from rhizosphere soil of Litchi (Litchi chinensis Sonn.) in Guangzhou, Guangdong Province, P.R. China. Phylogenetic analysis based on the 16S rRNA gene sequences showed that strains B11^T and D4^T belonged to the genus Flavobacterium and shared the highest similarity to Flavobacterium ginsenosidimutans THG 01^T (98.2%) and Flavobacterium daemonensis JCM 19455^T (98.0%), respectively. The DNA G+C contents of strains B11^T and D4^T were 33.9 and 34.1 mol%, respectively. Both the genome-derived average nucleotide identity and digital DNA-DNA hybridization values between the two strains and their closely related type species Flavobacterium sharifuzzamanii KCTC 62405^T and Flavobacterium denitrificans DSM 15936^T were below 39.3 and 90.5%, respectively. They all took iso-C_15:0 and summed feature 3 (C_16:1 ω6c and/or C_16:1  ω7c) as the major fatty acids. The polar lipids of strain B11^T contained phosphatidylethanolamine (PE), two unidentified aminophospholipids (APL1-2) and four unidentified lipids (L1-4), while strain D4^T took phosphatidylethanolamine (PE), three aminophospholipids (APL1-3) and four unidentified lipids (L1-4). Menaquinone-6 was their predominant quinone. Based on the phenotypic, chemotaxonomic, phylogenetic and genomic analyses, strains B11^T and D4^T should be considered as two novel species of the genus Flavobacterium, for which the names Flavobacterium movens (type strain B11^T=GDMCC 1.4103^T=JCM 36423^T) and Flavobacterium mesophilum (type strain D4^T=GDMCC 1.4105^T=JCM 36424^T) are proposed.