Pseudorivibacter rhizosphaerae gen. nov., sp. nov., isolated from rhizosphere soil of Camellia sinensis (L.) O. Ktze and emended description of the genus Rivibacter.

A Gram-stain-negative, facultative anaerobic, motile and straight rod-shaped bacterium, designated strain C1-9T, was isolated from rhizosphere soil of Camellia sinensis (L.) O. Ktze collected from a tea garden in Huize, south-western PR China. Cells were oxidase-positive and catalase-negative. Growth occurred at 20-40 °C and pH 6.0-10.0, with an optimal growth at 30 °C and pH 7.0. The respiratory quinone was detected as ubiquinone-8 (Q-8). The major fatty acids were identified as summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), C16 : 0 and summed feature 8 (C18 : 1ω7c or C18 : 1ω6c). The cellular polar lipids contained phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, three unidentified phospholipids, two unidentified lipids, one unidentified aminophospholipid and one unidentified aminolipid. The polyamine types were detected as 1,8-diaminooctane and 2-hydroxyputrescine. The genomic DNA G+C content was 68.6 mol%. Based on the results of 16S rRNA gene sequence analysis, strain C1-9T (MF687442) showed highest sequence similarity to Rivibacter subsaxonicus DSM 19570T (97.1 %). The phylogenetic tree based on 16S rRNA gene sequences showed that strain C1-9T clustered close to R. subsaxonicus DSM 19570T, Methylibium petroleiphilum CCTCC AB 2014193T and species belonging to the genera Rhizobacter and Piscinibacter. The phylogenomic tree indicated that strain C1-9T formed a clade with R. subsaxonicus. The average nucleotide identity value was 76.0 % between strain C1-9T and R. subsaxonicus DSM 19570T, which is lower than the prokaryotic species delineation threshold of 95.0-96.0 %. The polyphasic taxonomic characteristics indicated that strain C1-9T represents a novel species of a new genus within the order Burkholderiales, for which the name Pseudorivibacter rhizosphaerae gen. nov., sp. nov. (type strain C1-9T = KCTC 62325T=CGMCC 1.13864T) is proposed.

Flavisolibacter nicotianae sp. nov., isolated from rhizosphere soil of Nicotiana tabacum L.

A Gram-stain-negative, aerobic, non-motile and rod-shaped bacterium, designated strain X7XT, was isolated from a rhizosphere soil sample of Nicotiana tabacum L. collected from a tobacco factory located in Kunming, south-western China. The cells showed oxidase-positive and catalase-positive reactions. Growth occurred at 20-40 °C and pH 6.0-8.0, with optimal growth at 30 °C and pH 7.0. The predominant respiratory quinone was MK-7. The major fatty acids were identified as iso-C15 : 0, iso-C17 : 0 3OH and summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c). The cellular polar lipids contained phosphatidylethanolamine, an unidentified aminophospholipid, two unidentified glycolipids, four unidentified aminolipids and four unidentified lipids. The genomic DNA G+C content was 49.7 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain X7XT should be affiliated to the genus Flavisolibacter. Results from further analysis showed that strain X7XT had highest 16S rRNA gene sequence similarity to Flavisolibacter metallilatus TX0661T (96.4 %) and 'Flavisolibacter swuensis' SR2-4-2T (96.4 %), followed by other species of the genus Flavisolibacter. The polyphasic taxonomic characteristics indicated that strain X7XT represents a novel species of the genus Flavisolibacter, for which the name Flavisolibacternicotianae sp. nov. (type strain X7XT=KCTC 62326T=CGMCC 16451T) is proposed.