Verena Bartetzko

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C5: Virulence and avirulence function of the Xanthomonas campestris pv. vesicatoria type III effector protein XopJ

Principal investigator
Frederik Börnke

Mentor
Andreas Burkovski

PhD exam: 28.09.2012

Virulence and avirulence function of the Xanthomonas campestris pv. vesicatoria type III effector protein XopJ

Xanthomonas campestris pv. vesicatoria (Xcv) is the causal agent of bacterial spot disease in tomato and pepper. Xcv delivers about 25 effector proteins to the cytosol of the plant via its type III secretion system (T3SS).
In our previous work we determined the localisation of XopJ, a type III effector protein from Xanthomonas campestris pv. vesicatoria. Agroinfiltration of GFP fusions of XopJ showed that it localises at the plasma membrane involving most likely N-myristoylation and palmitoylation. By biochemical and microscopical approaches we revealed that its virulence function is based on at least partial disruption of pathogen related host cell trafficking. The inhibition of protein secretion is dependent on an intact catalytic triad and a putative myristoylation site of XopJ. During our studies we could also observe an avirulence function of XopJ. Treatment of XopJ-expressing N. benthamiana plants with salicylic acid exhibited a rapid hypersensitive response reaction depending on a functional catalytic triad and a correct localisation.
Further work will focus on microscopic techniques (confocal microscopy) and biochemical approaches to identify host targets of XopJ. Moreover purification of XopJ would give rise to the opportunity to investigate possible catalytic/ enzymatic activities of the protein, using various in vitro assays. By using this technique and other molecular and genetic approaches we want to examine the avirulence and virulence function of XopJ in more detail.

Figure A: Colocalisation of XopJ::GFP and a plasma membrane transporter mCherry fusion. The plasma membrane transporter localizes around the nucleus and in the plasma membrane whereas XopJ::GFP is attached to the plasma membrane via putative myristoylation and palmitoylation sites. Chloroplasts are shown in blue.
Figure B: XopJ represses callose deposition after infection. Ethanol-inducible XopJ-expressing Arabidopsis thaliana plants were infected with Pseudomonas syringae pv. tomato DC3000 (Pst), which was deficient in the T3SS. XopJ reduces callose depositions after infection of the plants with an avirulent Pst strain.

 

Publications

Lee, A. H.-Y., Hurley, B., Felsensteiner, C., Yea, C., Ckurshumova, W., Bartetzko, V., Wang, P. W., Quach, V., Lewis, J. D., Liu, Y. C., Börnke, F., Angers, S., Wilde, A., Guttman, D. S., and Desveaux, D. (2012). A Bacterial Acetyltransferase Destroys Plant Microtubule Networks and Blocks Secretion. PLoS Path 8(2), e1002523.

Bartetzko, V., Sonnewald, S., Vogel, F., Hartner, K., Stadler, R., Hammes, U. Z. and Börnke, F. (2009). The Xanthomonas campestris pv. vesicatoria Type III Effector Protein XopJ Inhibits Protein Secretion: Evidence for Interference with Cell Wall–Associated Defense Responses. Mol Plant Microbe Interact 22, 655-664.

 

Presentations

October 2011 First International SFB 796 Conference: Mechanisms of viral host cell manipulations: from plants to humans, Bamberg, Germany
Xanthomonas campestris pv. vesicatoria Type III Effector XopJ Inhibits Protein Secretion and Affects Host Cell Ubiquitination
Poster
     
August 2011 Plant Biology 2011, Minneapolis, USA
Xanthomonas campestris pv. vesicatoria Type III Effector XopJ Inhibits Protein Secretion and Affects Host Cell Ubiquitination
Poster
     
July 2011 3rd Annual Retreat "Erlangen School of Molecular Communication", Kloster Banz, Bad Staffelstein, Germany
Functional and Biochemical Characterisation of the Xanthomonas campestris pv. vesicatoria Type III Effector Protein XopJ
Talk
     
July 2011 3nd Annual Retreat "Erlangen School of Molecular Communication", Kloster Banz, Bad Staffelstein, Germany
Xanthomonas campestris pv. vesicatoria Type III Effector XopJ Inhibits Protein Secretion and Affects Host Cell Ubiquitination
Poster
     
May 2011 International Meeting "Communication in Plants and their Responses to the Environment", Collaborative Research Center SFB 648, Halle, Germany
Xanthomonas campestris pv. vesicatoria Type III Effector XopJ Inhibits Protein Secretion and Affects Host Cell Ubiquitination
Poster
     
September 2010 2nd Annual Retreat "Erlangen School of Molecular Communication", Kloster Banz, Bad Staffelstein, Germany
Functional and Biochemical Characterisation of the Xanthomonas campestris pv. vesicatoria Type III Effector Protein XopJ
Talk
     
September 2009 Botanikertagung 2009 Plants for the future. Leipzig, Germany
The Xanthomonas campestris pv. vesicatoria type III effector protein XopJ inhibits protein secretion: evidence for interference with cell wall – associated defense responses
Poster