Four new members of the family Cytophagaceae: Chryseosolibacter histidini gen. nov., sp. nov., Chryseosolibacter indicus gen. nov., sp. nov., Dawidia cretensis, gen. nov., sp. nov., and Dawidia soli, gen. nov., sp. nov. isolated from diverse habitat

Abstract

Four novel strains were isolated: PWU4T and PWU20T were both from soil in Germany, PWU5T was isolated from soil in India and PWU37T was obtained from sheep faeces collected on the Island of Crete. Cells of each were observed to be Gram-negative, strictly aerobic, rod shaped, and to grow optimally between 28 and 34 °C, between pH 7.0 and 8.0 and without the addition of NaCl. The strains were found to be catalase and oxidase-negative and able to grow on most mono- and disaccharides, a few polysaccharides and organic acids. Their predominant menaquinone was identified as MK-7. Their major fatty acids were identified as C16:1ω7c (PWU4T and PWU20T) and C16:1ω5c (PWU5T and PWU37T). The DNA G + C contents of strains PWU4T, PWU20T, PWU5T and PWU37T were determined to be 50.2 mol%, 51.6 mol %, 39.8 mol% and 53.8 mol%, respectively. The 16S rRNA gene sequence analysis revealed that the close relatives Ohtaekwangia koreensis 3B-2T and Ohtaekwangia kribbensis 10AOT share less than 93.8% sequence similarity. The strains were classified in two groups, where PWU4T and PWU20T share 93.0% sequence similarity, and PWU5T and PWU37T share 97.5% sequence similarity. However, the members of each group were concluded to represent different species based on the low average nucleotide identity (ANI) of their genomes, 69.7% and 83.8%, respectively. We propose that the four strains represent four novel species of two new genera in the family Cytophagaceae. The type species of the novel genus Chryseosolibacter is Chryseosolibacter histidini gen. nov., sp. nov. with the type strain PWU4T (= DSM 111594T = NCCB 100798T), whilst strain PWU20T (= DSM 111597T = NCCB 100800T) is the type strain of a second species, Chryseosolibacter indicus sp. nov. The type species of the novel genus Dawidia is Dawidia cretensis gen. nov., sp. nov. with the type strain PWU5T (= DSM 111596T = NCCB 100799T), whilst strain PWU37T (= DSM 111595T = NCCB 100801T) is the type stain of a second species, Dawidia soli sp. nov.

Arcicella gelida sp. nov. and Arcicella lustrica sp. nov., isolated from streams in China and re-examining the taxonomic status of all the genera within the families Spirosomataceae and Cytophagaceae

“…Although previous studies have improved the taxonomic classification of Bacteroidota , the current taxonomic problems among the species of these three families were mainly caused by the novel species proposed after 2019. The genera Aquirufa [7], Arundinibacter [37], and Tellurirhabdus [38] reported in 2019, Chryseotalea [39] and Sandaracinomonas [40] reported in 2020, and ‘ Chryseosolibacter ’ and ‘ Dawidia ’ [41] reported in 2022 were all assigned to the family Cytophagaceae . The genus Marinilongibacter reported in 2023 was assigned to the family Spirosomataceae [42].…”

International Committee on Systematics of Prokaryotes: Subcommittee on the taxonomy of aerobic Bacteroidota. Minutes of the online meeting 25 April 2023

“…Though focused mainly on myxobacteria, Richard Hahnke indicated some Bacteroidota genera have been described (e.g. ‘ Chryseosolibacter’ , ‘ Dawidia ’) [7] and further new discoveries could be possible. Ellen Frandsen heralded her retirement in October 2023 and also suggested a new member for the Subcommittee (action item 5).…”