Journal published updates to Lactobacillus genus

By Sophie Bullimore | Published: 17-Apr-2020

With the advance in genomic sequencing technology, this more precise and reliable method is overtaking phenotypic criteria as the new speciation standard

Incoming taxonomic changes to the genus Lactobacillus have now been published. As a highly commercialised organism, these changes will more than likely cause some confusion for the probiotic industry as the community adjusts labelling and research information.

The traditional approach to making taxonomic decisions was to look at phenotypic similarities for speciation. For this selection of microorganisms, phenotypic criteria such as fermentation patterns, enzymatic profiles and DNA-DNA hybridisation were used.

With the advance in genomic sequencing technology, this more precise and reliable method is becoming the new standard. These bacteria also have relatively small genome sizes so the method can be implemented sooner than for larger, more expensive organisms.

The paper states that the species once classified within the genus Lactobacillus should now be spread over 25 genera, of which 23 are novel genera, changes that been in discussion for years

In defence of the necessity for the changes the paper stated: "The current taxonomy, although widely accepted by the medical community, food and health-related industries, by lay-persons, and used in national and international regulations, impedes research aimed at understanding the ecology, physiology, evolution and applications of this important group of organisms. This is because microorganisms that are genetically very distinct and metabolically, ecologically and functionally very diverse are grouped within the same genus"

The paper added: "The lack of refined taxonomic structure, moreover, encourages the addition of new species to a genus that has already been shown to be overly heterogeneous and prevents the detection and description of functional properties or other commonalities shared between members of the subgroups."

The new paper, accepted by the Microbiology Society, has evaluated the taxonomy of Lactobacillaceae and Leuconostocaceae on the basis of their whole-genome sequences. The paper is titled: 'A taxonomic note on the genus Lactobacillus: Description of 23 novel genera, emended description of the genus Lactobacillus Beijerinck 1901, and union of Lactobacillaceae and Leuconostocaceae'.

Web tool

The confusion these changes would cause has been anticipated by the scientists behind the paper. As such, all the co-authros of the paper, including lead author Jinshui Zheng from the Huazhong Agricultural University in Wuhan, China, created a freely accessible search tool that allows you to find the new names of 250 species, previously assigned to the genus Lactobacillus but now referred to with a new genus name.

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