Thioredoxin reductase is a key factor in the oxidative stress response of <it>Lactobacillus plantarum </it>WCFS1

• Main Authors: Teusink Bas, Wels Michiel, Molenaar Douwe, Serrano L Mariela, Bron Peter A, de Vos Willem M, Smid Eddy J
• Format: Article
• Language: English
• Published: BMC 2007-08-01
• Series: Microbial Cell Factories
• Online Access: http://www.microbialcellfactories.com/content/6/1/29

<p>Abstract</p> <p>Background</p> <p>Thioredoxin (TRX) is a powerful disulfide oxido-reductase that catalyzes a wide spectrum of redox reactions in the cell. The aim of this study is to elucidate the role of the TRX system in the oxidative stress response in <it>Lactobacillus plantarum </it>WCFS1.</p> <p>Results</p> <p>We have identified the <it>trxB1</it>-encoded thioredoxin reductase (TR) as a key enzyme in the oxidative stress response of <it>Lactobacillus plantarum </it>WCFS1.</p> <p>Overexpression of the <it>trxB1 </it>gene resulted in a 3-fold higher TR activity in comparison to the wild-type strain. Subsequently, higher TR activity was associated with an increased resistance towards oxidative stress. We further determined the global transcriptional response to hydrogen peroxide stress in the <it>trxB1</it>-overexpression and wild-type strains grown in continuous cultures. Hydrogen peroxide stress and overproduction of TR collectively resulted in the up-regulation of 267 genes. Additionally, gene expression profiling showed significant differential expression of 27 genes in the <it>trxB1</it>-overexpression strain. Over expression of <it>trxB1 </it>was found to activate genes associated with DNA repair and stress mechanisms as well as genes associated with the activity of biosynthetic pathways for purine and sulfur-containing amino acids. A total of 16 genes showed a response to both TR overproduction and hydrogen peroxide stress. These genes are involved in the purine metabolism, energy metabolism (<it>gapB</it>) as well as in stress-response (<it>groEL</it>, <it>npr2</it>), and manganese transport (<it>mntH2</it>).</p> <p>Conclusion</p> <p>Based on our findings we propose that overproduction of the <it>trxB1</it>-encoded TR in <it>L. plantarum </it>improves tolerance towards oxidative stress. This response coincides with simultaneous induction of a group of 16 transcripts of genes. Within this group of genes, most are associated with oxidative stress response. The obtained crossover between datasets may explain the phenotype of the <it>trxB1</it>-overexpression strain, which appears to be prepared for encountering oxidative stress. This latter property can be used for engineering robustness towards oxidative stress in industrial strains of <it>L. plantarum</it>.</p>