sp. nov.，subsp. subsp. nov. 和 subsp. subsp. nov. 分别从昆虫病原线虫中分离得到。

sp. nov., subsp. subsp. nov. and subsp. subsp. nov. isolated from entomopathogenic nematodes.

机构信息

Experimental Biology Research Group, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland.

Division of Nematology, Indian Council of Agricultural Research, Indian Agricultural Research Institute (ICAR-IARI), New Delhi, India.

出版信息

Int J Syst Evol Microbiol. 2021 Sep;71(9). doi: 10.1099/ijsem.0.004998.

DOI:10.1099/ijsem.0.004998

PMID:34524954

Abstract

Two Gram-negative, rod-shaped bacteria, H1 and H3, isolated from the digestive tract of entomopathogenic nematodes were biochemically and molecularly characterized to determine their taxonomic positions. The 16S rRNA gene sequences of these strains indicate that they belong to the Gammaproteobacteria, to the family , and to the genus. Deeper analyses using whole genome-based phylogenetic reconstructions show that strains H1 and H3 are closely related to DSM 15138, to DSM 22397, and to PB45.5. genomic comparisons confirm these observations and show that strain H1 shares 70.6, 66.8, and 63.5 % digital DNA-DNA hybridization (dDDH) with DSM 15138, DSM 22397, and PB45.5, respectively, and that strain H3 shares 76.6, 69.4, and 59.2 % dDDH with DSM 15138, DSM 22397, and PB45.5, respectively. Physiological and biochemical characterization reveals that these two strains differ from most of the validly described species and from their more closely related taxa. Given the clear phylogenetic separations, that the threshold to discriminate species and subspecies is 70 and 79% dDDH, respectively, and that strains H1 and H3 differ physiologically and biochemically from their more closely related taxa, we propose to classify H1 and H3 into new taxa as follows: H3 as a new subspecies within the species , and H1 as a new species within the genus, in spite that H1 shares 70.6 % dDDH with DSM 15138, score that is slightly higher than the 70 % threshold that delimits species boundaries. The reason for this is that H1 and DSM 15138 cluster apart in the phylogenetic trees and that dDDH scores between strain H1 and other strains are lower than 70 %. Hence, the following names are proposed: sp. nov. with the type strain H1 (=IARI-SGMG3,=KCTC 82683=CCM 9150=CCOS 1975) and subsp. subsp. nov. with the type strain H3 (=IARI-SGHR2=KCTC 82684=CCM 9149=CCOS 1976). These propositions automatically create subsp. subsp. nov. with DSM 15138 as the type strain (currently classified as ).

摘要

从昆虫病原线虫消化道中分离到的 2 株革兰氏阴性、杆状细菌 H1 和 H3，通过生化和分子特征分析来确定它们的分类地位。这些菌株的 16S rRNA 基因序列表明它们属于γ变形菌门、弧菌科和弧菌属。基于全基因组的系统发育重建的更深入分析表明，菌株 H1 和 H3 与 DSM 15138、DSM 22397 和 PB45.5.5 密切相关。基因组比较证实了这些观察结果，并表明菌株 H1 与 DSM 15138、DSM 22397 和 PB45.5 分别具有 70.6%、66.8%和 63.5%的数字 DNA-DNA 杂交（dDDH），而菌株 H3 与 DSM 15138、DSM 22397 和 PB45.5 分别具有 76.6%、69.4%和 59.2%的 dDDH。生理生化特征表明，这两株菌与大多数有效描述的种以及与其亲缘关系较近的分类群不同。鉴于明确的系统发育分离，区分种和亚种的阈值分别为 70%和 79% dDDH，并且菌株 H1 和 H3 在生理和生化上与与其亲缘关系较近的分类群不同，我们建议将 H1 和 H3 分类为新的分类群，如下所示：H3 为种内的新亚种，H1 为属内的新种，尽管 H1 与 DSM 15138 具有 70.6%的 dDDH，略高于区分种界限的 70%阈值。原因是 H1 和 DSM 15138 在系统发育树中分开聚类，并且菌株 H1 与其他菌株之间的 dDDH 评分低于 70%。因此，提出以下名称：新种，其模式株为 H1（=IARI-SGMG3，=KCTC 82683=CCM 9150=CCOS 1975）和新亚种。弧菌亚种。新亚种，其模式株为 H3（=IARI-SGHR2=KCTC 82684=CCM 9149=CCOS 1976）。这些提议自动创建了以 DSM 15138 为模式株的新亚种。弧菌亚种。新亚种（目前归类为）。