Neorhizobium turbinariae sp. nov., a coral-beneficial bacterium isolated from Turbinaria peltata

Coral reef ecosystems are facing decline due to climate change, overfishing, habitat destruction and pollution. Bacteria play an essential role in maintaining the stability of coral reef ecosystems, influencing the well-being and fitness of coral hosts. The exploitation of coral probiotics has become an urgent issue. A short-rod shaped aerobic bacterium, designated NTR19 T , was isolated in a healthy coral Turbinaria peltata from Daya Bay, Shenzhen, PR China. Its cells were Gram-negative, motile with a polar flagellum. The activities of catalase and oxidase were positive. Strain NTR19 T grew at 10–41 °C (optimum, 28 °C), with NaCl concentrations of 0–4 % (w/v; optimum, 0.5 %) and at pH 5.0–9.5 (optimum, pH 7.0–7.5). The predominant fatty acids (>10 %) were summed feature 8 (57.6 %), C 19 : 0 cyclo ω8 c (12.6 %) and C 16 : 0 (12.0 %). The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phospholipid and phosphatidylcholine. The major respiratory quinone was Q-10. The draft genome was 4.68 Mbp with 61.2 mol% DNA G+C content. In total, 4477 coding sequences were annotated and there were 64 RNA genes. The average nucleotide identity (ANI) and average amino acid identity (AAI) values between strain NTR19 T and the related Neorhizobium species were 78.23–79.70% and 80.26–80.50 %, respectively. This strain encoded many proteins for the activities of catalase and oxidase in the genome. Strain NTR19 T was clearly distinct from its closest neighbours Rhizobium oryzicola ACCC 05753 T and Neorhizobium petrolearium ACCC 11238 T with the 16S rRNA gene sequence similarity values of 96.86 and 96.36 %, respectively. The results of phylogenetic analysis, as well as ANI and AAI values, revealed that strain NTR19 T belongs to Neorhizobium and was distinct from other species of this genus. The physiological, biochemical and chemotaxonomic characteristics also supported the species novelty of strain NTR19 T . Thus, strain NTR19 T is considered to be classified as a novel species in the genus Neorhizobium , for which the name Neorhizobium turbinariae sp. nov. is proposed. The type strain is NTR19 T (=JCM 35342 T =MCCC 1K07226 T ).