The Histidine Decarboxylase Gene Cluster of Lactobacillus parabuchneri Was Gained by Horizontal Gene Transfer and Is Mobile within the Species.

Daniel Wüthrich,Stefan Irmler,Rémy Bruggmann,Hélène Berthoud,Elisabeth Eugster,Daniel Wechsler

doi:10.3389/fmicb.2017.00218

Daniel Wüthrich, Stefan Irmler + Show 4 more

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https://doi.org/10.3389/fmicb.2017.00218

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Abstract

Histamine in food can cause intolerance reactions in consumers. Lactobacillus parabuchneri (L. parabuchneri) is one of the major causes of elevated histamine levels in cheese. Despite its significant economic impact and negative influence on human health, no genomic study has been published so far. We sequenced and analyzed 18 L. parabuchneri strains of which 12 were histamine positive and 6 were histamine negative. We determined the complete genome of the histamine positive strain FAM21731 with PacBio as well as Illumina and the genomes of the remaining 17 strains using the Illumina technology. We developed the synteny aware ortholog finding algorithm SynOrf to compare the genomes and we show that the histidine decarboxylase (HDC) gene cluster is located in a genomic island. It is very likely that the HDC gene cluster was transferred from other lactobacilli, as it is highly conserved within several lactobacilli species. Furthermore, we have evidence that the HDC gene cluster was transferred within the L. parabuchneri species.

Highlights

Biogenic amines are basic nitrogenous compounds found in foods and in beverages
We found strong evidence that the histidine decarboxylase (HDC) gene cluster was introduced to the genome of L. parabuchneri by horizontal gene transfer and that the HDC gene cluster is located on a genomic island (HDC island, Figure 2A)
We found that the HDC gene cluster is conserved in species that are used in food production (Coton et al, 1998; Lucas et al, 2005; Satomi et al, 2011) and species that are adapted to the human body as habitat

Summary

Introduction

Biogenic amines are basic nitrogenous compounds found in foods and in beverages. They are synthesized by the decarboxylation of amino acids. The formation of histamine in fermented food such as cheese and wine is related to Gram-positive bacteria. When L. buchneri St2A and L. buchneri Lb14 were used as adjuncts in cheese making, the cheeses developed high levels of histamine (Sumner et al, 1985; Joosten and Northolt, 1989; Choudhury et al, 1990) Both strains, which are deposited in the Belgian coordinated Collection of Microorganisms and German Collection of Microorganisms and Cell Cultures, were reidentified as Lactobacillus parabuchneri (L. parabuchneri LMG 11773 and L. parabuchneri DSM 5987)

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