Identification of the trehalose biosynthetic loci of Pseudomonas syringae and their contribution to fitness in the phyllosphere
Article first published online: 18 FEB 2010
© 2010 Society for Applied Microbiology and Blackwell Publishing Ltd
Special Issue: Pseudomonas. Editors: Professors Burkhard Tummler, Victor de Lorenzo, Alain Filloux and Joyce Loper
Volume 12, Issue 6, pages 1486–1497, June 2010
How to Cite
Freeman, B. C., Chen, C. and Beattie, G. A. (2010), Identification of the trehalose biosynthetic loci of Pseudomonas syringae and their contribution to fitness in the phyllosphere. Environmental Microbiology, 12: 1486–1497. doi: 10.1111/j.1462-2920.2010.02171.x
- Issue published online: 3 JUN 2010
- Article first published online: 18 FEB 2010
- Received 13 November, 2009; accepted 18 December, 2009.
Surprisingly little is known of the trehalose biosynthetic pathways in pseudomonads, despite the importance of trehalose to protecting cells from environmental stresses such as low water availability. The genome of the foliar pathogen Pseudomonas syringae pv. tomato strain DC3000 contains genes for two trehalose biosynthetic pathways, TreS and TreYZ, and lacks genes for the more common OtsAB pathway. Deletion of either the treS (PSPTO_2760-2762) or treY/treZ (PSPTO_3125-3134) locus eliminated trehalose accumulation and reduced bacterial growth under hyperosmotic conditions. In evaluating the role of trehalose in P. syringae fitness on leaves, we found that a double deletion mutant lacking these loci exhibited poorer survival than the wild type on tomato leaves over a 2-week period in a growth chamber. Similarly, this mutant exhibited reduced survival on leaves of susceptible and resistant cultivars of the host plant tomato and of the non-host plant soybean over a 10-day period in field plots. Thus, the trehalose biosynthetic loci in P. syringae, which are highly conserved among pseudomonads, contributed to DC3000 fitness on leaves, supporting a role for trehalose in P. syringae survival and population maintenance in the phyllosphere.