Limnobacter alexandrii sp. nov., a thiosulfate-oxidizing, heterotrophic and EPS-bearing Burkholderiaceae isolated from cultivable phycosphere microbiota of toxic Alexandrium catenella LZT09

• Published in: Antonie van Leeuwenhoek 2020-11, Vol.113 (11), p.1689-1698
• Main Authors: Duan, Yuhan, Jiang, Zhiwei, Wu, Zheng, Sheng, Zhi, Yang, Xi, Sun, Jingya, Zhang, Xiaoling, Yang, Qiao, Yu, Xinwei, Yan, Jianbo
• Format: Article
• Language: English
• Subjects: Biomedical and Life Sciences; Life Sciences; Medical Microbiology; Microbiology; Original Paper; Plant Sciences; Soil Science & Conservation
• ISSN: 0003-6072; 1572-9699
• DOI: 10.1007/s10482-020-01473-8

A novel Gram-negative, aerobic, motile and short rod-shaped bacterium with exopolysaccharides production, designated as LZ-4 T , was isolated from cultivable phycosphere microbiota of harmful algal blooms-causing marine dinoflagellate Alexandrium catenella LZT09 which produces paralytic shellfish poisoning toxins. Strain LZ-4 T was able to use thiosulfate (optimum concentration 10 mM) as energy source for bacterial growth. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain LZ-4 T belonged to the genus Limnobacter , showing high 16S rRNA gene sequences similarities with L. thiooxidans DSM 13612 T (99.4%), L. humi NBRC 11650 T (98.2%) and L. litoralis NBRC 105857 T (97.2%), respectively. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between LZ-4 T and L. thiooxidans DSM 13612 T were 78.9 and 21.9%, respectively. Both values were far lower than the thresholds (95–96% for ANI and 70% for dDDH) generally accepted for new species delineation. The respiratory quinone of strain LZ-4 T was Q-8. The dominant cellular fatty acids were determined as summed feature 3 (C 16:1 ω 6c/ ω 7c), summed feature 8 (C 18:1 ω 6c/ ω 7c) and C 16:0 . Polar lipids profile consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, two unidentified aminolipids and three unidentified polar lipids. The genomic DNA G+C content of strain LZ-4 T was 52.5 mol%. Based on polyphasic characterization, strain LZ-4 T represents a novel species of the genus Limnobacter , for which the name Limnobacter alexandrii sp. nov. is proposed. The type strain is LZ-4 T (=CCTCC AB 2019004 T  =KCTC 72281 T ).