Serratia entomophila bet gene induction and the impact of glycine betaine accumulation on desiccation tolerance
Article first published online: 27 DEC 2012
© 2012 AgResearch
Journal of Applied Microbiology
Volume 114, Issue 2, pages 470–481, February 2013
How to Cite
Sheen, T.R., O'Callaghan, M., Smalley, D.J., Ronson, C.W. and Hurst, M.R.H. (2013), Serratia entomophila bet gene induction and the impact of glycine betaine accumulation on desiccation tolerance. Journal of Applied Microbiology, 114: 470–481. doi: 10.1111/jam.12052
- Issue published online: 14 JAN 2013
- Article first published online: 27 DEC 2012
- Accepted manuscript online: 30 OCT 2012 02:29AM EST
- Manuscript Accepted: 15 OCT 2012
- Manuscript Revised: 14 OCT 2012
- Manuscript Received: 8 JUN 2012
- New Zealand Foundation for Research, Science and Technology (FRST). Grant Number: C10X0301
- DNA hairpin;
- glycine betaine;
The genes involved in choline transport and oxidation to glycine betaine in the biopesticidal bacterium Serratia entomophila were characterized, and the potential of osmoprotectants, coupled with increased NaCl concentrations, to improve the desiccation tolerance of this species was investigated.
Methods and Results
Serratia entomophila carries sequences similar to the Escherichia coli betTIBA genes encoding a choline transporter and dehydrogenase, a betaine aldehyde dehydrogenase and a regulatory protein. Disruption of betA abolished the ability of Ser. entomophila to utilize choline as a carbon source. Quantitative reverse-transcriptase PCR analysis revealed that betA transcription was reduced compared to that of the upstream genes in the operon, and that NaCl and choline induced bet gene expression. Glycine betaine and choline increased the NaCl tolerance of Ser. entomophila, and osmotically preconditioned cultures survived better than control cultures following desiccation and immediately after application to agricultural soil.
Addition of glycine betaine and NaCl to growth medium can greatly enhance the desiccation survival of Ser. entomophila, and its initial survival in soil.
Significance and Impact of the Study
Serratia entomophila is sensitive to desiccation and does not persist under low soil moisture conditions. Techniques described here for enhancing the desiccation survival of Ser. entomophila can be used to improve formulations of this bacterium, and allow its application under a wider range of environmental conditions.