Analysis of new type III effectors from Xanthomonas uncovers XopB and XopS as suppressors of plant immunity
Article first published online: 27 JUN 2012
© 2012 The Authors. New Phytologist © 2012 New Phytologist Trust
Volume 195, Issue 4, pages 894–911, September 2012
How to Cite
Schulze, S., Kay, S., Büttner, D., Egler, M., Eschen-Lippold, L., Hause, G., Krüger, A., Lee, J., Müller, O., Scheel, D., Szczesny, R., Thieme, F. and Bonas, U. (2012), Analysis of new type III effectors from Xanthomonas uncovers XopB and XopS as suppressors of plant immunity. New Phytologist, 195: 894–911. doi: 10.1111/j.1469-8137.2012.04210.x
- Issue published online: 2 AUG 2012
- Article first published online: 27 JUN 2012
- Received: 28 March 2012, Accepted: 15 May 2012
- bacterial spot disease;
- Capsicum annuum (pepper);
- cell death suppression;
- type III secretion;
- vesicle trafficking;
- Xanthomonas campestris
- •The pathogenicity of the Gram-negative plant-pathogenic bacterium Xanthomonas campestris pv. vesicatoria (Xcv) is dependent on type III effectors (T3Es) that are injected into plant cells by a type III secretion system and interfere with cellular processes to the benefit of the pathogen.
- •In this study, we analyzed eight T3Es from Xcv strain 85-10, six of which were newly identified effectors. Genetic studies and protoplast expression assays revealed that XopB and XopS contribute to disease symptoms and bacterial growth, and suppress pathogen-associated molecular pattern (PAMP)-triggered plant defense gene expression.
- •In addition, XopB inhibits cell death reactions induced by different T3Es, thus suppressing defense responses related to both PAMP-triggered immunity (PTI) and effector-triggered immunity (ETI).
- •XopB localizes to the Golgi apparatus and cytoplasm of the plant cell and interferes with eukaryotic vesicle trafficking. Interestingly, a XopB point mutant derivative was defective in the suppression of ETI-related responses, but still interfered with vesicle trafficking and was only slightly affected with regard to the suppression of defense gene induction. This suggests that XopB-mediated suppression of PTI and ETI is dependent on different mechanisms that can be functionally separated.