Roseateles caseinilyticus sp. nov. and Roseateles cellulosilyticus sp. nov., isolated from rice paddy field soil

Abstract

Two novel Gram-stain-negative strains designated P7^T and P8^T, were isolated from the soil of a paddy field in Goyang, Republic of Korea, and identified as new species within the genus Roseateles through a polyphasic taxonomic approach. These aerobic, rod-shaped, non-sporulating strains demonstrated optimal growth at 30 °C, pH 7, and in the absence of NaCl (0% w/v). Phylogenetic analysis based on 16S rRNA gene sequences indicated close relationships with Roseateles saccharophilus DSM654^T (98.7%) and Roseateles puraquae CCUG 52769^T (98.96%), respectively. The average nucleotide identity (ANI) and digital DNA–DNA hybridization (dDDH) values between the isolates with the most closely related strains with publicly available whole genomes were 82.0–85.5% and 25.0–30.2%, respectively. The predominant fatty acids identified were C_16:0 and summed feature 3 (composed of C_16:1 ω6c and/or C_16:1 ω7c), with minor amounts of C_12:0, C_10:0 3–OH and summed feature 8 (composed of C_18:1 ω7c and/or C_18:1 ω6c; 26.4%). Ubiquinone 8 was the main quinone, and the polar lipid profile included phosphatidylethanolamine, phosphatidylglycerol, two unidentified phosphoaminolipids, one unidentified phosphoglycolipid, three unidentified phospholipids, and one unidentified aminolipid. The draft genome sequences revealed genomic DNA G + C contents of 70.1% for P7^T and 68.2% for P8^T. Comprehensive physiological, biochemical, and 16S rRNA sequence analyses confirm these isolates as novel species of the genus Roseateles, proposed to be named Roseateles caseinilyticus sp. nov for strain P7^T (= KACC 22504^T = TBRC 15694^T) and Roseateles cellulosilyticus sp. nov. for strain P8^T (= KACC 22505^T = TBRC 15695^T).