These authors contributed equally to this work.
Detailed analysis of the DNA recognition motifs of the Xanthomonas type III effectors AvrBs3 and AvrBs3Δrep16
Article first published online: 22 JUN 2009
© 2009 The Authors. Journal compilation © 2009 Blackwell Publishing Ltd
The Plant Journal
Volume 59, Issue 6, pages 859–871, September 2009
How to Cite
Kay, S., Hahn, S., Marois, E., Wieduwild, R. and Bonas, U. (2009), Detailed analysis of the DNA recognition motifs of the Xanthomonas type III effectors AvrBs3 and AvrBs3Δrep16. The Plant Journal, 59: 859–871. doi: 10.1111/j.1365-313X.2009.03922.x
- Issue published online: 9 SEP 2009
- Article first published online: 22 JUN 2009
- Received 12 March 2009; revised 7 May 2009; accepted 8 May 2009. published online 22 June 2009.
- UPA box;
- Capsicum annuum;
The Gram-negative phytopathogenic bacterium Xanthomonas campestris pv. vesicatoria (Xcv) employs a type III secretion system to translocate effector proteins into plant cells where they modulate host signaling pathways to the pathogen’s benefit. The effector protein AvrBs3 acts as a eukaryotic transcription factor and induces the expression of plant genes termed UPA (up-regulated by AvrBs3). Here, we describe 11 new UPA genes from bell pepper that are induced by AvrBs3 early after infection with Xcv. Sequence comparisons revealed the presence of a conserved AvrBs3-responsive element, the UPA box, in all UPA gene promoters analyzed. Analyses of UPA box mutant derivatives confirmed its importance for gene induction by AvrBs3. We show that DNA binding and gene activation were strictly correlated. DNase I footprint studies demonstrated that the UPA box corresponds to the center of the AvrBs3-protected DNA region. Type III delivery of AvrBs3 and mutant derivatives showed that some UPA genes are induced by the AvrBs3 deletion derivative AvrBs3Δrep16, which lacks four repeats. We show that AvrBs3Δrep16 recognizes a mutated UPA box with two nucleotide exchanges in positions that are not essential for binding and activation by AvrBs3.