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 <i>Sonneratia apetala</i> 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 <i>Micropruina glycogenica</i> Lg2^T and shared the highest 16S rRNA gene sequence similarity of 98.2% with <i>M. glycogenica</i> Lg2^T. The average nucleotide identity and estimated digital DNA-DNA hybridization values between strain KQZ13P-5^T and <i>M. glycogenica</i> 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(H₄) as the predominant menaquinone. The cell wall diagnostic diamino acid was <i>meso</i>-diaminopimelic acid (DAP). Based on phylogenetic, genomic, phenotypic and chemotaxonomic data, strain KQZ13P-5^T represents a novel species of genus <i>Micropruina</i> for which the name <i>Micropruina sonneratiae</i> sp. nov. is proposed. The type strain is KQZ13P-5^T (=JCM 34552^T= CGMCC 1.18968^T). The description of the genus <i>Micropruina</i> has also been emended.