Phycicoccus flavus sp. nov., a novel endophytic actinobacterium isolated from branch of Kandelia candel

A Gram-stain-positive, aerobic, non-motile, non-endospore-forming and rod-shaped actinobacterium, designated strain CMS6Z-2(T), was isolated from a surface-sterilized branch of Kandelia candel collected from the Maowei Sea, Guangxi Zhuang Autonomous Region, PR China. Strain CMS6Z-2(T) grew at 10-37 degrees C (optimum, 37 degrees C), pH 6.0-9.0 (optimum, pH 7.0-8.0) and in the presence of 0-10.0% (w/v) NaCl (optimum, 0-1.0%). Strain CMS6Z-2(T) possessed meso-diaminopimelic acid as the diamino acid of the peptidoglycan and MK-8 (H 4) as the predominant menaquinone. The major fatty acids were iso-C 15:0, C 16:0 and C 18:1.9c. The polar lipids comprised diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and two unknown phospholipids. The G+C content of the genomic DNA was 74.1mol%. Comparative analysis of 16S rRNA genes showed that strain CMS6Z-2(T) should be assigned to the genus Phycicoccus and its closest relative was Phycicoccus endophyticus IP6SC6(T) with 98.3% similarity. Phylogenetic analyses based on 16S rRNA gene sequence and phylogenomic analysis based on core proteomes alignment revealed that strain CMS6Z-2(T) belonged to the genus Phycicoccus and formed a robust cluster with Phycicoccus endophyticus IP6SC6(T) within the genus Phycicoccus. The average nucleotide identity value and estimated digital DNA-DNA hybridization value between strain CMS6Z-2(T) and the type strain of Phycicoccus endophyticus were 81.5 and 23.9%, respectively. On the basis of phylogenetic, phenotypic and chemotaxonomic characteristics, strain CMS6Z-2(T) represents a novel species of the genus Phycicoccus, for which the name Phycicoccus flavus sp. nov. is proposed. The type strain is CMS6Z-2(T) (=KCTC 49240(T)=CGMCC4.7549(T)).