Phycicoccus sonneraticus sp. nov., a Novel Endophytic Actinobacterium Isolated from the Bark of Sonneratia apetala.

A novel endophytic actinobacterial strain, designated MQZ13P-5, was isolated from a piece of bark of Sonneratia apetala, collected from Guangxi Zhuang Autonomous Region, China. This strain was Gram-stain positive, aerobic, non-spore-forming, non-motile and rod-shaped. Comparative 16S rRNA gene sequence analysis showed that strain MQZ13P-5 was related to the genus Phycicoccus with exhibiting the highest similarity (98.0%) to Phycicoccus endophyticus IP6SC6. The phylogenetic trees based on 16S rRNA gene sequences and core genes indicated that strain MQZ13P-5 belonged to the genus Phycicoccus and could not be assigned to any described species. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strain MQZ13P-5 and type strains of Phycicoccus species were less than 84% and 27%, respectively, below the thresholds for species delineation. This strain showed chemotaxonomic and phenotypic properties consistent with its classification in the genus Phycicoccus. Based on the taxonomic data, strain MQZ13P-5 should represent a novel species of the genus Phycicoccus, for which the name Phycicoccus sonneraticus sp. nov. is proposed, with the type strain MQZ13P-5 (= CGMCC 1.18744 = JCM 34337).