Pseudomonas rhizoryzae sp. nov., isolated from rice

Two yellow-pigmented, Gram-stain-negative and rod-shaped bacterial strains, designated as RY24(T) and ZYY160, were isolated from rice. Results of phylogenetic analysis based on 16S rRNA gene sequences showed that strains RY24(T) and ZYY160 belonged to the genus Pseudomonas, and the 16S rRNA gene sequence similarity was 100 % The DNA homology between the two strains was 99.7 %. The 16S rRNA and rpoD gene sequences of the two strains showed highest similarity values to Pseudomonas oryzihabitans CGMCC 1.3392(T) and Pseudomonas psychrotolerans DSM 15758(T) (sharing 99.31 and 94.34 %, respectively). The major fatty acids of two strains were identified as summed feature 8 (C im agc and/or C-18:1 omega 6c), C-16.0 and summed feature 3 (C-16:1 omega 7c and/or C-16:1 omega 6c), and the major respiratory quinone was identified as ubiquinone Q-9, which are typical chemotaxonomic features of members of the genus Pseudomonas. The genomic DNA G+C contents of strains RY24(T) and ZYY160 were determined to be 64.25 and 64.21 mol%, respectively. The DNA-DNA relatedness and average nucleotide identity values between the two strains and their closely related type strains were below 36 and 90 %, which supported that RY24(T) and ZYY160 represent a novel species in the genus Pseudomonas. Phylogenetic and chemotaxonomic evidence, together with phenotypic characteristics, showed that the two isolates constitute a novel species of the genus Pseudomonas. The type strain is RY24(T) (JCM 33201(T)=ACCC 61555(T)), for which the name Pseudomonas rhizoryzae sp. nov. is proposed.