Rhizobium glycinendophyticum sp. nov., isolated from roots of Glycine max (Linn. Merr.).

A Gram-stain-negative, rod-shaped and aerobic bacterium, designated CL12, was isolated from roots of Glycine max (Linn. Merr.) collected from an experimental field in the campus of South China Agricultural University, PR China (22°5846″S, 110°51'10″E). Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain CL12 belongs to the genus Rhizobium, closely related to Rhizobium wuzhouense W44 (99.3%), followed by Rhizobium rosettiformans W3 (98.0%) and Rhizobium ipomoeae Shin9-1 (97.9%). The results of analysis of sequences of four housekeeping genes (recA, atpD, rpoB and glnA) also revealed strain CL12 to be closely related to R. wuzhouense W44 with the similarities 91.0%, 95.0%, 94.2% and 90.5%, respectively. The major fatty acid of strain CL12 was Summed Feature 8 (Cω7c and/or Cω6c). Strain CL12 had not the nodulation genes (nodC and nodA) and nitrogenase reductase gene (nifH), and could not cause formation of nodule on soybean. The draft genome size of strain CL12 was 4.84 Mbp with a genomic DNA G + C content of 61.1 mol%. The digital DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) of strain CL12 and R. wuzhouense W44 were 27.4% and 84.7%, respectively. Based on genomic, phenotypic and phylogenetic analysis, strain CL12 is suggested to represent a new species of the genus Rhizobium, for which the name Rhizobium glycinendophyticum sp. nov. is proposed. The type strain is CL12 (=GDMCC 1.1597 = KACC 21281).