Micropruina sonneratiae sp. nov., a novel endophytic actinobacterium isolated from bark of Sonneratia apetala and emended description of the genus Micropruina

A novel strain, KQZ13P-5 T , was isolated from the bark of Sonneratia apetala collected from Maowei Sea Mangrove Nature Reserve of Guangxi Zhuang Autonomous Region, China. Cells of strain KQZ13P-5 T were Gram-stain-positive, aerobic and non-spore producing. A polyphasic taxonomic approach was investigated to resolve its taxonomic position. The conditions for the growth of strain KQZ13P-5 T were at 20–37 °C (optimum 30–37 °C), pH 5.0–8.5 (optimum pH 6.5–7.5) and with 0–4% (w/v) NaCl (optimum 0%). Phylogenetic analysis based on 16S rRNA gene sequence and genome sequence showed that strain KQZ13P-5 T formed a stable and coherent branch with Micropruina glycogenica Lg2 T and shared the highest 16S rRNA gene sequence similarity of 98.2% with M. glycogenica Lg2 T . The average nucleotide identity and estimated digital DNA–DNA hybridization values between strain KQZ13P-5 T and M. glycogenica Lg2 T were 80.2% and 24.0%, respectively, far below the interspecies threshold. The G+C content of DNA of strain KQZ13P-5 T was 70.5%. The polar lipids included diphosphatidylglycerol, phosphatidylglycerol, two unidentified lipids and one unidentified glycolipid. It contained anteiso-C 15 : 0 , iso-C 16 : 0 and C 16 : 0 as the major fatty acids and MK-9(H 4 ) as the predominant menaquinone. The cell wall diagnostic diamino acid was meso -diaminopimelic acid (DAP). Based on phylogenetic, genomic, phenotypic and chemotaxonomic data, strain KQZ13P-5 T represents a novel species of genus Micropruina for which the name Micropruina sonneratiae sp. nov. is proposed. The type strain is KQZ13P-5 T (=JCM 34552 T = CGMCC 1.18968 T ). The description of the genus Micropruina has also been emended.