Glycine betaine improves Listeria monocytogenes tolerance to desiccation on parsley leaves independent of the osmolyte transporters BetL, Gbu and OpuC
Article first published online: 1 NOV 2007
© 2007 The Authors
Journal of Applied Microbiology
Volume 104, Issue 4, pages 1221–1227, April 2008
How to Cite
Dreux, N., Albagnac, C., Sleator, R.D., Hill, C., Carlin, F., Morris, C.E. and Nguyen-the, C. (2008), Glycine betaine improves Listeria monocytogenes tolerance to desiccation on parsley leaves independent of the osmolyte transporters BetL, Gbu and OpuC. Journal of Applied Microbiology, 104: 1221–1227. doi: 10.1111/j.1365-2672.2007.03623.x
- Issue published online: 27 NOV 2007
- Article first published online: 1 NOV 2007
- 2007/0629: received 20 April 2007, revised 9 August 2007 and accepted 14 September 2007
- compatible solutes;
- fresh produce;
- glycine betaine;
- Listeria monocytogenes;
- relative humidity
Aims: To investigate the effect of glycine betaine (GB) on the survival of Listeria monocytogenes on leaf surfaces under low relative humidity (RH).
Methods and Results: The addition of GB (≥25 mmol l−1) improved the survival of L. monocytogenes under low RH on parsley leaves, thus suggesting that GB can improve the tolerance of L. monocytogenes to desiccation. Ten times less GB was needed to improve L. monocytogenes survival under low RH on nonbiological surfaces compared with parsley leaves, suggesting that, on the leaf surface, L. monocytogenes may have to compete for the available GB with autochthonous bacteria and/or the plant itself. Wild type and mutants carrying deletions in the three GB uptake systems, BetL, Gbu and OpuC, behaved similarly with and without added GB on parsley leaves (P > 0·05). In addition, preaccumulation of GB, triggered by osmotic stress prior to inoculation, failed to improve survival under low RH compared with osmotic stress without GB accumulation.
Conclusions: Exogenous GB had a protective effect on L. monocytogenes cells from desiccation during survival on parsley leaves. This effect was independent of intracellular GB accumulation by the known uptake systems.
Significance and Impact of the Study: Presence of GB could improve the survival of L. monocytogenes to desiccation on leaf surfaces and nonbiological surfaces.