Polyphasic taxonomy of glacier-derived Variovorax strains reveals 13 novel species

Seventeen bacterial strains were isolated from cryoconite and glacial ice samples collected from five glaciers in China. Phylogenetic analyses based on 16S rRNA gene sequences placed these strains within the genus <i>Variovorax</i>. Pairwise average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) comparisons among the 17 strains supported their assignment to 13 separate genomic species. The highest ANI (≤94.2%) and dDDH (≤60.5%) values between them and their closest type strains were below the accepted species thresholds, indicating that they cannot be assigned to any known <i>Variovorax</i> species. Consistently, the phylogenomic tree resolved 13 well-supported, independent lineages corresponding to these genomic species. The major cellular fatty acids in the majority of strains were C<sub>16 : 0</sub>, summed feature 3 (C<sub>16:1</sub> <i>ω</i>7<i>c</i> and/or C<sub>16:1</sub> <i>ω</i>6<i>c</i>) and summed feature 8 (C<sub>18:1</sub> ω7c and/or C<sub>18:1</sub> <i>ω</i>6<i>c</i>). Based on combined phenotypic, genotypic and phylogenetic evidence, the 17 strains represent 13 novel species of the genus <i>Variovorax</i>, for which the following names are proposed: <i>Variovorax glucosi</i> sp. nov. (RHLX14ᵀ=CGMCC 1.10104<sup>T</sup>=NBRC 116946<sup>T</sup>), <i>Variovorax frigidus</i> sp. nov. (LT1R16ᵀ=CGMCC 1.11618<sup>T</sup>=NBRC 116947<sup>T</sup>), <i>Variovorax trehalosi</i> sp. nov. (LT1R20ᵀ=CGMCC 1.11621<sup>T</sup>=NBRC 116948<sup>T</sup>), <i>Variovorax restrictus</i> sp. nov. (LT1P1ᵀ=CGMCC 1.11725<sup>T</sup>=NBRC 116949<sup>T</sup>), <i>Variovorax cryoconiti</i> sp. nov. (LT2P21<sup>T</sup>=CGMCC 1.11737<sup>T</sup>=NBRC 116950<sup>T</sup>), <i>Variovorax pasteuri</i> sp. nov. (RB3P1<sup>T</sup>=CGMCC 1.11853<sup>T</sup>=NBRC 116951<sup>T</sup>), <i>Variovorax nivicola</i> sp. nov. (ZT5P49<sup>T</sup>=CGMCC 1.23581<sup>T</sup>=NBRC 116952<sup>T</sup>), <i>Variovorax multivorans</i> sp. nov. (ZT5R36<sup>T</sup>=CGMCC 1.23587<sup>T</sup>=NBRC 116953<sup>T</sup>), <i>Variovorax nitratireducens</i> sp. nov. (RT4R15<sup>T</sup>=CGMCC 1.24376<sup>T</sup>=NBRC 116954<sup>T</sup>), <i>Variovorax monticola</i> sp. nov. (GB4P3<sup>T</sup>=CGMCC 1.24632<sup>T</sup>=NBRC 116955<sup>T</sup>), <i>Variovorax raffinosi</i> sp. nov. (GB1P17<sup>T</sup>=CGMCC 1.24747<sup>T</sup>=NBRC 116956<sup>T</sup>), <i>Variovorax glacialis</i> sp. nov. (GT1P44<sup>T</sup>=CGMCC 1.24874<sup>T</sup>=NBRC 116957<sup>T</sup>) and <i>Variovorax sucrosi</i> sp. nov. (ZT4R33<sup>T</sup>=CGMCC 1.25067<sup>T</sup>=NBRC 116958<sup>T</sup>).

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INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY
Published
2026-03-16
DOI
https://doi.org/10.1099/ijsem.0.007105
Primary Topic
Polar Research and Ecology
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article

Polyphasic taxonomy of glacier-derived Variovorax strains reveals 13 novel species

Ziyun Chen, Yu Xin, Qing Liu
INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY
Polar Research and Ecology
article

Polyphasic taxonomy of glacier-derived Variovorax strains reveals 13 novel species

Ziyun Chen, Yu Xin, Qing Liu
article en

Abstract

Seventeen bacterial strains were isolated from cryoconite and glacial ice samples collected from five glaciers in China. Phylogenetic analyses based on 16S rRNA gene sequences placed these strains within the genus <i>Variovorax</i>. Pairwise average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) comparisons among the 17 strains supported their assignment to 13 separate genomic species. The highest ANI (≤94.2%) and dDDH (≤60.5%) values between them and their closest type strains were below the accepted species thresholds, indicating that they cannot be assigned to any known <i>Variovorax</i> species. Consistently, the phylogenomic tree resolved 13 well-supported, independent lineages corresponding to these genomic species. The major cellular fatty acids in the majority of strains were C<sub>16 : 0</sub>, summed feature 3 (C<sub>16:1</sub> <i>ω</i>7<i>c</i> and/or C<sub>16:1</sub> <i>ω</i>6<i>c</i>) and summed feature 8 (C<sub>18:1</sub> ω7c and/or C<sub>18:1</sub> <i>ω</i>6<i>c</i>). Based on combined phenotypic, genotypic and phylogenetic evidence, the 17 strains represent 13 novel species of the genus <i>Variovorax</i>, for which the following names are proposed: <i>Variovorax glucosi</i> sp. nov. (RHLX14ᵀ=CGMCC 1.10104<sup>T</sup>=NBRC 116946<sup>T</sup>), <i>Variovorax frigidus</i> sp. nov. (LT1R16ᵀ=CGMCC 1.11618<sup>T</sup>=NBRC 116947<sup>T</sup>), <i>Variovorax trehalosi</i> sp. nov. (LT1R20ᵀ=CGMCC 1.11621<sup>T</sup>=NBRC 116948<sup>T</sup>), <i>Variovorax restrictus</i> sp. nov. (LT1P1ᵀ=CGMCC 1.11725<sup>T</sup>=NBRC 116949<sup>T</sup>), <i>Variovorax cryoconiti</i> sp. nov. (LT2P21<sup>T</sup>=CGMCC 1.11737<sup>T</sup>=NBRC 116950<sup>T</sup>), <i>Variovorax pasteuri</i> sp. nov. (RB3P1<sup>T</sup>=CGMCC 1.11853<sup>T</sup>=NBRC 116951<sup>T</sup>), <i>Variovorax nivicola</i> sp. nov. (ZT5P49<sup>T</sup>=CGMCC 1.23581<sup>T</sup>=NBRC 116952<sup>T</sup>), <i>Variovorax multivorans</i> sp. nov. (ZT5R36<sup>T</sup>=CGMCC 1.23587<sup>T</sup>=NBRC 116953<sup>T</sup>), <i>Variovorax nitratireducens</i> sp. nov. (RT4R15<sup>T</sup>=CGMCC 1.24376<sup>T</sup>=NBRC 116954<sup>T</sup>), <i>Variovorax monticola</i> sp. nov. (GB4P3<sup>T</sup>=CGMCC 1.24632<sup>T</sup>=NBRC 116955<sup>T</sup>), <i>Variovorax raffinosi</i> sp. nov. (GB1P17<sup>T</sup>=CGMCC 1.24747<sup>T</sup>=NBRC 116956<sup>T</sup>), <i>Variovorax glacialis</i> sp. nov. (GT1P44<sup>T</sup>=CGMCC 1.24874<sup>T</sup>=NBRC 116957<sup>T</sup>) and <i>Variovorax sucrosi</i> sp. nov. (ZT4R33<sup>T</sup>=CGMCC 1.25067<sup>T</sup>=NBRC 116958<sup>T</sup>).

INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGYVol. 76(3)
Chinese Academy of Sciences (CN), Peking University (CN), Institute of Microbiology (CN), China Agricultural University (CN)
Life below water
Openalex Percentile: Top 24%
Polar Research and Ecology
DOISourceOpenAlex
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