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

ABSTRACT

Bacterial strain H4R21T 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 H4R21T belongs to the genus Collimonas with high sequence similarity to C. arenae Ter10T (99.38 %), C. fungivorans Ter6T(98.97 %), C. pratensis Ter91T (98.76 %), C. humicola RLT1W51T (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 H4R21T is ubiquinone-8 (Q8). The major polar lipids are diphosphatidylglycerol, phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol and lipid. The major fatty acids identified were C12  0, C120 3-OH, C16    0 and C170 cyclo. 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 H4R21T represents a novel species within the genus Collimonas, for which the name Collimonas rhizosphaerae sp. nov. is proposed, with strain H4R21T (=CFBP 9203T=DSM 117599T) as the type strain.