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Author: Ralf Koebnik
Internal reviewer:
Expert reviewer: WANTED!

Class: XopAZ
Family: XopAZ
Prototype: XopAZ (Xanthomonas hortorum pv. cynarae, formerly Xanthomonas cynarae; strain CFBP 4188) (Kara, 2016)
GenBank ID: MCE4349711.1 (157 aa)
RefSeq ID: WP_104549896.1 (157 aa)
3D structure: Unknown

Biological function

How discovered?

A cosmid library was created from genomic DNA of X. cynarae and the cosmid clone library was screened in X. perforans strain ME24. The transconjugants were infiltrated into tomato to identify the clones which resulted in rapid necrosis, characteristic of an HR. Three of the clones elicited HRs in tomato. One of the clones was subcloned and the fragments were tested for ability to elicit an HR in tomato. One of the subclones elicited an HR and was determined to contain a 510 bp open reading frame (ORF). BLAST analysis of the nucleotide sequence revealed 98.6% sequence identity with a peptidylprolyl isomerase gene in X. gardneri strain ICMP 7893 (Kara et al., 2017). This effector protein, which was called XopAZ in a poster presented at APS Meeting in 2017, had 169 aa with 12 extra amino acids at the N terminus (MHSTRSPSWRFP) (Kara et al., 2017).

(Experimental) evidence for being a T3E

Whether the protein is an effector delivered by the type III secretion system was tested using a reporter system in which 70 amino acids at the N-terminus of the candidate gene was fused to the C-terminus of AvrBs2 as described previously (Roden et al., 2004). When a bacterial suspension of the X. euvesicatoria strain Ted 3 that did not contain avrBs2, but that was carrying the vector encoding the fusion protein, was infiltrated into pepper leaves containing Bs2 (ECW-20R) and pepper leaves without Bs2 (ECW), an HR was observed only in ECW-20R.




Enzymatic function

Predicted peptidylprolyl isomerase.

Interaction partners


In xanthomonads

Universally conserved protein, e.g. Xanthomonas melonis (Ramnarine et al., 2022).

In other plant pathogens/symbionts

Universally conserved protein.


Kara S (2016). Characterization of a new type three secretion effector in Xanthomonas cynarae. Doctoral Thesis. University of Florida, Gainesville, USA. PDF:

Kara S, Timilsina S, Jacques MA, Potnis N, Vallad G, Fischer-Le Saux M, Hurlbert JC, Minsavage GV, Jones JB (2017). A novel type III Xop effector in Xanthomonas cynarae associated with rapid cell death. Phytopathology 107: S5.88. DOI: 10.1094/PHYTO-107-12-S5.1

Ramnarine SDBJ, Jayaraman J, Ramsubhag A (2022). Comparative genomics of the black rot pathogen Xanthomonas campestris pv. campestris and non-pathogenic co-inhabitant Xanthomonas melonis from Trinidad reveal unique pathogenicity determinants and secretion system profiles. PeerJ 9: e12632. DOI: 10.7717/peerj.12632

Roden JA, Belt B, Ross JB, Tachibana T, Vargas J, Mudgett MB (2004). A genetic screen to isolate type III effectors translocated into pepper cells during Xanthomonas infection. Proc. Natl. Acad. Sci. U. S. A. 101: 16624-16629. DOI: 10.1073/pnas.0407383101

bacteria/t3e/xopaz.txt · Last modified: 2023/10/05 09:30 by rkoebnik