Taxonomic characterization and secondary metabolic profiling of three novel species of the genus Kinneretia isolated from crater Lake water.

Many species of family Sphaerotilaceae have been isolated from aquatic environments. In this study, we conducted the taxonomic characterization of five novel strains Y2R2-4T, B2R-40T, DJ2R-2T, DJ1R-11 and DJ4R-1, isolated from crater lakes in Da Hinggan Mountain region of northern China. A polyphasic taxonomic approach was employed to determine the taxonomic affiliation of these strains. Based on the 16S rRNA gene sequence analysis, these novel strains showed the highest similarities (98.9-99.9%) to Kinneretia aquatilis CR182T and Kinneretia alba hw1T. While the digital DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) between the five novel strains and their closely related species Kinneretia were significantly below the established taxonomic thresholds for species delineation, further supporting that these strains represent three novel species within the genus Kinneretia. Based on genomic annotation results, their metabolic potentials to produce terpene and RiPP-like compounds were further explored. In summary, the morphological, physiological, and biochemical characteristics of these novel strains indicated that the five isolates represent three novel species within the genus Kinneretia. The names, Kinneretia craterilacus sp. nov., Kinneretia daxingganlingensis sp. nov. and Kinneretia lacustris sp. nov., were proposed for them, with type strain Y2R2-4T (= CGMCC 1.19001T = KCTC 92188T), B2R-40T (= CGMCC 1.19003T = KCTC 92190T) and DJ2R-2T (= CGMCC 1.19002T = KCTC 92189T), respectively.