Christendat Lab

Cell and Systems Biology, University of Toronto

Protocatechuate Biosynthesis in L. monocytogenes

Aromatic compounds play a key role in soil microbe populations. They can act as another carbon source or as a precursor to secondary metabolites for microbes. Many of these microorganisms form complex interactions with plants and thus heavily influence plant life and by extension, our environment.  Our lab takes an interest in aromatics such as shikimate pathway derivatives and how they shape the the global microbial landscape. One approach our lab employs, involves studying the metabolism of shikimate pathway products in a food-borne pathogen and soil saprophyte, Listeria monocytogenes[1].

L. monocytogenes is a hardy gram-positive bacteria capable of surviving a wide range of  difficult environments. This bacteria is capable of growing on a variety of food products, is often associated with contaminated vegetation, and causes the dangerous condition known as listeriosis[1]. Due to ubiquitous presence of aromatic compounds such as quinate and shikimate in plants, it is unsurprising that L. monocytogenes has two operons responsible for quinate metabolism. These operons named qui1 and qui2 encode an assortment of enzymes capable of catalyzing various steps in the shikimate pathway. Our lab has recently found that L. monocytogenes can utilize quinate and shikimate to produce protocatechuate. Although protocatechuate is often used as a carbon source or for siderophore biosynthesis, L. monocytogenes is unable to utilize protocatechuate in these established ways[2].

We aim to understand how Listeria monocytogenes may be utilizing protocatechuate in its environment.

Model for protocatechuate biosynthesis in Listeria monocytogenes.

  1. Ottesen, A., et al. 2016. Enrichment Dynamics of Listeria monocytogenes and the Associated Microbiome from Naturally Contaminated Ice Cream Linked to a listeriosis Outbreak. BMC Microbiology. 16 (275).
  2. Prezioso, S., et al. 2018. Shikimate Induced Transcriptional Activation of Protocatechuate Biosynthesis Genes by QuiR, a LysR-Type Transcriptional Regulator, in Listeria monocytogenes. J. Mol. Bio. 430(9):1265-1283.

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