This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Zhao, Y. Articles by Sundin, G. W. Search for Related Content PubMed PubMed Citation Articles by Zhao, Y. Articles by Sundin, G. W.

 Previous Article  |  Next Article 

Journal of Bacteriology, December 2005, p. 8088-8103, Vol. 187, No. 23
0021-9193/05/$08.00+0     doi:10.1128/JB.187.23.8088-8103.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.

Identification of Erwinia amylovora Genes Induced during Infection of Immature Pear Tissue

Youfu Zhao, Sara E. Blumer, and George W. Sundin^*

Department of Plant Pathology and Center for Microbial Pathogenesis, Michigan State University, 103 Center for Integrated Plant Systems, East Lansing, Michigan 48824

Received 14 July 2005/ Accepted 16 September 2005

The enterobacterium Erwinia amylovora is a devastating plant pathogen causing necrotrophic fire blight disease of apple, pear, and other rosaceous plants. In this study, we used a modified in vivo expression technology system to identify E. amylovora genes that are activated during infection of immature pear tissue, a process that requires the major pathogenicity factors of this organism. We identified 394 unique pear fruit-induced (pfi) genes on the basis of sequence similarity to known genes and separated them into nine putative function groups including host-microbe interactions (3.8%), stress response (5.3%), regulation (11.9%), cell surface (8.9%), transport (13.5%), mobile elements (1.0%), metabolism (20.3%), nutrient acquisition and synthesis (15.5%), and unknown or hypothetical proteins (19.8%). Known virulence genes, including hrp/hrc components of the type III secretion system, the major effector gene dspE, type II secretion, levansucrase (lsc), and regulators of levansucrase and amylovoran biosynthesis, were upregulated during pear tissue infection. Known virulence factors previously identified in E. (Pectobacterium) carotovora and Pseudomonas syringae were identified for the first time in E. amylovora and included HecA hemagglutinin family adhesion, Peh polygalacturonase, new effector HopPtoC_EA, and membrane-bound lytic murein transglycosylase MltE_EA. An insertional mutation within hopPtoC_EA did not result in reduced virulence; however, an mltE_EA knockout mutant was reduced in virulence and growth in immature pears. This study suggests that E. amylovora utilizes a variety of strategies during plant infection and to overcome the stressful and poor nutritional environment of its plant hosts.

Y. F. Zhao and S. E. Blumer contributed equally to this work.

This article has been cited by other articles:

• Chen, Z., Agnew, J. L., Cohen, J. D., He, P., Shan, L., Sheen, J., Kunkel, B. N. (2007). Pseudomonas syringae type III effector AvrRpt2 alters Arabidopsis thaliana auxin physiology. Proc. Natl. Acad. Sci. USA 104: 20131-20136 [Abstract] [Full Text]  
• Oh, H.-S., Kvitko, B. H., Morello, J. E., Collmer, A. (2007). Pseudomonas syringae Lytic Transglycosylases Coregulated with the Type III Secretion System Contribute to the Translocation of Effector Proteins into Plant Cells. J. Bacteriol. 189: 8277-8289 [Abstract] [Full Text]  
• Tamir-Ariel, D., Navon, N., Burdman, S. (2007). Identification of Genes in Xanthomonas campestris pv. vesicatoria Induced during Its Interaction with Tomato. J. Bacteriol. 189: 6359-6371 [Abstract] [Full Text]  
• Triplett, L. R., Zhao, Y., Sundin, G. W. (2006). Genetic Differences between Blight-Causing Erwinia Species with Differing Host Specificities, Identified by Suppression Subtractive Hybridization. Appl. Environ. Microbiol. 72: 7359-7364 [Abstract] [Full Text]