Arboriscoccus pini gen. nov., sp. nov., an endophyte from a pine tree of the class Alphaproteobacteria, emended description of Geminicoccus roseus, and proposal of Geminicoccaceae fam. nov.

Bacterial strain B29T1T was isolated from the endophytic microbial community of a Pinus pinaster tree trunk and characterized. Strain B29T1T stained Gram-negative and formed diplococci that grew optimally at 26-30°C and at pH 6.0-7.0. The G+C content of the DNA was 61.6mol%. The respiratory quinone was ubiquinone 10 (UK-10), and the major fatty acids were C16:0 , cyclo-C19:0 ω8c and C18:0 12-methyl, representing 64% of the total fatty acids. Phylogenetic analyses based on the 16S rRNA gene sequences placed strain B29T1T within the order Rhodospirillales in a distinct lineage that also included the genus Geminicoccus. The 16S rRNA gene sequence similarities of B29T1T to that of Candidatus Alysiomicrobium bavaricum, Geminicoccus roseus and Candidatus Alysiosphaera europeae were 92.6%, 89.9% and 89.2%, respectively. The analysis of the available genomes from the closest families showed 177 core genes that reveals a novel family-level clade including the type strain of the genus Geminicoccus and the strain B29T1T . Analysis of B29T1T genome revealed all the genes involved in autotrophic carbon dioxide fixation via the reductive pentose phosphate pathway and genes encoding for starch/glycogen and chitin degradation. The phylogenetic, phenotypic and chemotaxonomic data showed that strain B29T1T (=CIP 110763T , =LMG 27745T ) represents the type of a novel species and genus, for which we propose the name Arboriscoccus pini gen. nov., sp. nov. A new family (Geminicoccaceae fam. nov.) is proposed for Arboriscoccus, Geminicoccus, Candidatus Alysiomicrobium and Candidatus Alysiosphaera. The description of the Geminicoccus roseus DSM 18922T is also emended.