Table of Contents

The Type III Effector XopO from //Xanthomonas//

Author: Harrold van den Burg
Internal reviewer: Jakub Pečenka
Expert reviewer: Zoe Dubrow

Class: XopO
Family: XopO
Prototype: XopO (Xanthomonas euvesicatoria pv. euvesicatoria, ex Xanthomonas campestris pv. vesicatoria; strain 85-10)
GenBank ID: AAV74207.1 (220 aa)
RefSeq ID: WP_011346566.1 (211 aa)
3D structure: Unknown

Biological function

How discovered?

XopO was identified in a genetic screen, using a Tn5-based transposon construct harboring the coding sequence for the HR-inducing domain of AvrBs2, but devoid of the effectors' T3SS signal, that was randomly inserted into the genome of X. campestris pv. vesicatoria (Xcv)strain 85-10. The XopO::AvrBs2 fusion protein triggered a Bs2-dependent hypersensitive response (HR) in pepper leaves (Roden et al., 2004).

(Experimental) evidence for being a T3E

Type III-dependent secretion was confirmed using a calmodulin-dependent adenylate cyclase reporter assay, with a ΔhrpF mutant strain serving as negative control (Roden et al., 2004).

Regulation

XopO was found to be regulated by HrpG using HrpG* (Roden et al., 2004). XopO contains a PIP box sequence 31bp upstream of the -10 promoter motif (Koebnik et al., 2006).

Phenotypes

Localization

Unknown.

Enzymatic function

Unknown.

Interaction partners

XopO was shown to interact with tomato 14-3-3 (TFT) proteins (Dubrow et al., 2018).

Conservation

In xanthomonads

Yes, in some xanthomonads (e.g., X. euvesicatoria, X. oryzae) (Lang et al., 2019). XopO is a differential T3E gene between Xoo and Xoc (Hajri et al., 2012).

In other plant pathogens/symbionts

Yes, e.g. homologs (AvrRps4 and HopK1) in Pseudomonas syringae (Li et al., 2014).

References

Barak JD, Vancheva T, Lefeuvre P, Jones JB, Timilsina S, Minsavage GV, Vallad GE, Koebnik R (2016) Whole-genome sequences of Xanthomonas euvesicatoria strains clarify taxonomy and reveal a stepwise erosion of type 3 effectors. Front Plant Sci. 7: 1805. DOI: 10.3389/fpls.2016.01805

Dubrow Z, Sunitha S, Kim JG, Aakre CD, Girija AM, Sobol G, Teper D, Chen YC, Ozbaki-Yagan N, Vance H, Sessa G, Mudgett MB (2018). Tomato 14-3-3 proteins are required for Xv3 disease resistance and interact with a subset of Xanthomonas euvesicatoria effectors. Mol. Plant Microbe Interact. 31: 1301-1311. DOI: 10.1094/MPMI-02-18-0048-R

Hajri A, Brin C, Zhao S, David P, Feng JX, Koebnik R, Szurek B, Verdier V, Boureau T, Poussier S (2012). Multilocus sequence analysis and type III effector repertoire mining provide new insights into the evolutionary history and virulence of Xanthomonas oryzae. Mol. Plant Pathol. 13: 288-302. DOI: 10.1111/j.1364-3703.2011.00745.x

Koebnik R, Krüger A, Thieme F, Urban A, Bonas U (2006). Specific binding of the Xanthomonas campestris pv. vesicatoria AraC-type transcriptional activator HrpX to plant-inducible promoter boxes. J. Bacteriol. 188: 7652-7660. DOI: 10.1128/JB.00795-06

Lang JM, Pérez-Quintero AL, Koebnik R, DuCharme E, Sarra S, Doucoure H, Keita I, Ziegle J, Jacobs JM, Oliva R, Koita O, Szurek B, Verdier V, Leach JE (2019). A pathovar of Xanthomonas oryzae infecting wild grasses provides insight into the evolution of pathogenicity in rice agroecosystems. Front. Plant Sci. 10: 507. DOI: 10.3389/fpls.2019.00507

Li G, Froehlich JE, Elowsky C, Msanne J, Ostosh AC, Zhang C, Awada T, Alfano JR, (2014). Distinct Pseudomonas type-III effectors use a cleavable transit peptide to target chloroplasts. Plant J. 77: 310–321. DOI: 10.1111/tpj.12396

Popov G, Fraiture M, Brunner F, Sessa G (2016). Multiple Xanthomonas euvesicatoria type III effectors inhibit flg22-triggered immunity. Mol. Plant Microbe Interact. 29: 651-660. DOI: 10.1094/MPMI-07-16-0137-R

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. USA 101: 16624-16629. DOI: 10.1073/pnas.0407383101

Sohn KH, Zhang Y, Jones JD (2009). The Pseudomonas syringae effector protein, AvrRPS4, requires in planta processing and the KRVY domain to function. Plant J. 57: 1079-1091. DOI: 10.1111/j.1365-313X.2008.03751.x FIXME Information needs to be added to the profile.

Teper D, Sunitha S, Martin GB, Sessa G (2015). Five Xanthomonas type III effectors suppress cell death induced by components of immunity-associated MAP kinase cascades. Plant Signal. Behav. 10: e1064573. DOI: 10.1080/15592324.2015.1064573

Acknowledgements

This fact sheet is based upon work from COST Action CA16107 EuroXanth, supported by COST (European Cooperation in Science and Technology).