Thioclava kandeliae sp. nov., Isolated from the Rhizosphere Soil of Mangrove Plant Kandelia candel.

A Gram-stain-negative, non-motile, aerobic bacterium, designated as strain CPCC 100088, was isolated from a rhizosphere soil sample of Kandelia candel in a mangrove. Growth of strain CPCC 100088 was observed at 15-37 °C, pH 6.0-9.0, and in the presence of 0-7% (w/v) NaCl with optimal growth at 28-32 °C, pH 6.0-7.0 and in the absence of NaCl. This strain was positive for catalase and oxidase activity. The major respiratory quinone was Q-10. Phosphatidylethanolamine and phosphatidylglycerol were the predominant polar lipids. The major fatty acids were C and summed feature 8 (Cω7c/Cω6c). Strain CPCC 100088 shared the highest 16S rRNA gene sequence similarity (96.4%) with Thioclava pacifica DSM 10166 and Thioclava marina 11.10-0-13, followed by 95.5-95.8% with other members of the genus Thioclava. In the phylogenetic trees reconstructed using 16S rRNA gene or based on the whole genomes, strain CPCC 100088 was within the Thioclava phylogenetic clade within the family Paracoccaceae. The whole-genome of strain CPCC 100088 consisted of 4.3 Mbp with the G + C content of 61.3%. The digital DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) values (19.6% and 74.4%) based on whole-genome sequences of strain CPCC 100088 and its closest phylogenetic neighbour species were below the threshold for species delineation. Based on the phenotypic and genotypic data, we propose that strain CPCC 100088 represents a novel species of the genus Thioclava, for which the name Thioclava kandeliae sp. nov. is proposed, with CPCC 100088 (= I07B-00821 = KCTC 32191) as the type strain.