Collimonas rhizosphaerae sp. nov., a novel species isolated from the beech rhizosphere

Bacterial strain H4R21^T was isolated from beech rhizosphere soil sampled in the forest experimental site of Montiers (Meuse, France). It effectively weathers minerals, hydrolyses chitin and produces quorum sensing signal molecules. The strain is aerobic and Gram-stain-negative. Phylogenetic analysis based on its 16S rRNA gene sequence indicated that strain H4R21^T belongs to the genus Collimonas with high sequence similarity to C. arenae Ter10^T (99.38 %), C. fungivorans Ter6^T(98.97 %), C. pratensis Ter91^T (98.76 %), C. humicola RLT1W51^T (98.46 %) and C. silvisoli RXD178 ^T (98.46 %), but less than 98 % similarity to other strains of the genus Collimonas. The predominant quinone in H4R21^T is ubiquinone-8 (Q8). The major polar lipids are diphosphatidylglycerol, phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol and lipid. The major fatty acids identified were C_12 : 0, C_12:0 3-OH, C_{16  :  0} and C_17:0cyclo. The digital DNA G+C content of the genomic DNA was 59.5 mol%. Furthermore, the strain could be clearly distinguished from its closely related type strains by a combination of phylogenomic and in silico DNA-DNA hybridization results, and phenotypic characteristics. Therefore, strain H4R21^T represents a novel species within the genus Collimonas, for which the name Collimonas rhizosphaerae sp. nov. is proposed, with strain H4R21^T (=CFBP 9203^T=DSM 117599^T) as the type strain.