The Lactococcus lactis KF147 nonribosomal peptide synthetase/polyketide synthase system confers resistance to oxidative stress during growth on plant leaf tissue lysate

Microbiologyopen. 2018 Feb;7(1):e00531. doi: 10.1002/mbo3.531. Epub 2017 Sep 18.


Strains of Lactococcus lactis isolated from plant tissues possess adaptations that support their survival and growth in plant-associated microbial habitats. We previously demonstrated that genes coding for a hybrid nonribosomal peptide synthetase/polyketide synthase (NRPS/PKS) system involved in production of an uncharacterized secondary metabolite are specifically induced in L. lactis KF147 during growth on plant tissues. Notably, this NRPS/PKS has only been identified in plant-isolated strains of L. lactis. Here, we show that the L. lactis KF147 NRPS/PKS genes have homologs in certain Streptococcus mutans isolates and the genetic organization of the NRPS/PKS locus is conserved among L. lactis strains. Using an L. lactis KF147 mutant deficient in synthesis of NrpC, a 4'-phosphopantetheinyl transferase, we found that the NRPS/PKS system improves L. lactis during growth under oxidative conditions in Arapidopsis thaliana leaf lysate. The NRPS/PKS system also improves tolerance of L. lactis to reactive oxygen species and specifically H2 O2 and superoxide radicals in culture medium. These findings indicate that this secondary metabolite provides a novel mechanism for reactive oxygen species detoxification not previously known for this species.

Keywords: Lactococcus lactis; NRPS/PKS; Plant-associated bacteria; natural products; reactive oxygen species; secondary metabolites.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Conserved Sequence
  • Hydrogen Peroxide / toxicity
  • Lactococcus lactis / enzymology*
  • Lactococcus lactis / genetics
  • Lactococcus lactis / growth & development
  • Oxidative Stress*
  • Peptide Synthases / genetics
  • Peptide Synthases / metabolism*
  • Plant Extracts / metabolism*
  • Plant Leaves / chemistry*
  • Polyketide Synthases / genetics
  • Polyketide Synthases / metabolism*
  • Reactive Oxygen Species / toxicity
  • Sequence Homology
  • Streptococcus mutans / enzymology
  • Streptococcus mutans / genetics
  • Stress, Physiological*


  • Plant Extracts
  • Reactive Oxygen Species
  • Polyketide Synthases
  • Hydrogen Peroxide
  • Peptide Synthases
  • non-ribosomal peptide synthase

Associated data

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