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New Insights Into the Threshold Values of Multi-Locus Sequence Analysis, Average Nucleotide Identity and Digital DNA–DNA Hybridization in Delineating Streptomyces Species

Multi-locus sequence analysis (MLSA) has been proved to be a useful method for Streptomyces identification and MLSA distance of 0.007 is considered as the boundary value. However, we found that MLSA distance of 0.007 might be insufficient to act as a threshold according to the correlations among ave...

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Detalles Bibliográficos
Autores principales: Hu, Siren, Li, Kaiqin, Zhang, Yifei, Wang, Yinfeng, Fu, Li, Xiao, Yan, Tang, Xinke, Gao, Jian
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9195134/
https://www.ncbi.nlm.nih.gov/pubmed/35711787
http://dx.doi.org/10.3389/fmicb.2022.910277
Descripción
Sumario:Multi-locus sequence analysis (MLSA) has been proved to be a useful method for Streptomyces identification and MLSA distance of 0.007 is considered as the boundary value. However, we found that MLSA distance of 0.007 might be insufficient to act as a threshold according to the correlations among average nucleotide identity based on MuMmer ultra-rapid aligning tool (ANIm), digital DNA–DNA hybridization (dDDH) and MLSA from the 80 pairs of Streptomyces species; in addition, a 70% dDDH value did not correspond to a 95∼96% ANIm value but approximately to 96.7% in the genus Streptomyces. Based on our analysis, it was proposed that when the MLSA distance value between a novel Streptomyces and a reference strain was < 0.008, the novel strain could be considered as a heterotypic synonym of the reference strain; when the MLSA distance value was ≥ 0.014, the novel strain could be regarded as a new Streptomyces species; when the MLSA distance value was between 0.008 and 0.014 (not included), the dDDH or ANIm value between a new strain and a reference strain must be calculated in order to determine the taxonomic status of a novel strain. In this context, a 70% dDDH or 96.7% ANIm value could act as the threshold value in delineating Streptomyces species, but if the dDDH or ANIm value was less than but close to 70 or 96.7% cut-off point, the taxonomic status of a novel strain could only be determined by a combination of phenotypic characteristics, chemotaxonomic characteristics and phylogenomic analysis.