====== The Type III Effector XopH from //Xanthomonas// ======

Author: Isabel Rodrigues\\
Internal reviewer: [[https://www.researchgate.net/profile/Camila_Fernandes2|Camila Fernandes]]\\
Expert reviewer: **WANTED!**

Class: XopH\\
Family: XopH1, XopH2\\
Prototype: AvrBs1.1 (//Xanthomonas euvesicatoria// pv. //euvesicatoria//, ex// Xanthomonas campestris// pv. //vesicatoria//; strain E3) (Ronald and Staskawicz, 1988)\\
GenBank ID (AvrBs1.1): [[https://www.ncbi.nlm.nih.gov/protein/P0A0W1.1|P0A0W1.1]] (104 aa)\\
GenBank ID (XopH1): [[https://www.ncbi.nlm.nih.gov/protein/CAP51755.1|CAP51755.1]] (356 aa)\\
RefSeq ID: XopH1 [[https://www.ncbi.nlm.nih.gov/protein/WP_011345706.1|WP_011345706.1]] (356 aa), XopH2 [[https://www.ncbi.nlm.nih.gov/protein/WP_010377341.1|WP_010377341.1]] (380 aa)\\
Synonym: AvrBs1.1, AvrBs7 (Potnis //et al.//, 2012)\\
3D structure: [[https://swissmodel.expasy.org/repository/uniprot/P0A0W1|P0A0W1]] (homology model)

===== Biological function =====

=== How discovered? ===

The XopH effector, also known as AvrBs1.1 (White //et al//., 2009), was first reported in 1988 (Ronald and Staskawicz 1988) and discovered due to its virulent activity (Gurenn //et al//., 2006). Later, this effector began to be identified based on the coregulation with the TTS system (Gurlebeck //et al//., 2006), most recently began to be identified by a combination of biochemical approaches, including a new NMR-based method to discriminate inositol polyphosphate enantiomers (Blüher //et al//., 2017).
=== (Experimental) evidence for being a T3E ===

The effector XopH, inhibited flg22-induced callose deposition //in planta// (Popov //et al//., 2016), dephosphorylates myo- inositol-hexakisphosphate (phytate, InsP6) to produce InsP5[1-OH], both //in vitro// and //in vivo,// and enhanced disease symptoms (Blüher //et al//., 2017; White and Jones 2018). The xopH activity can led to diminishing amounts of inositol pyrophosphates InsP7 and InsP8 (White and Jones 2018). It was also identified host changes in gene expression due to XopH activity (White and Jones 2018).
=== Regulation ===

Unknown.

=== Phenotypes ===

This effector can inhibit flg22- but not ABA-inducible reporter gene activation in protoplasts act as PTI inhibitors in planta and contribute to development of disease symptoms like chlorosis (Popov //et al//., 2016). XopH liberates phosphate from the plant tissue to improve the nutritional status of the pathogen what causes the plant show obvious symptoms of phosphorus deficiency (Blüher //et al//., 2017). Transgenic //Nicotiana benthamiana// plants constitutively expressing XopH were significantly smaller than transgenic GFP control plants of the same age and showed signs of early senescence indicating that the effector XopH might affect the ET pathway (Blüher //et al//., 2017). XopH sequester InsP6 by degrading it to an InsP5 isomer, which is not easily metabolized by the plant and accumulates what can compromise plant defense mechanism (Blüher //et al//., 2017).
=== Localization ===

The effector XopH is localized in the nucleus and in the cytoplasm of the plant cell (Popov //et al//., 2016; Blüher //et al//., 2017).
=== Enzymatic function ===

XopH is a T3E with phytate-degrading activity, //in vitro// and //in planta// (Blüher //et al//., 2017).
=== Interaction partners ===

Unknown.

===== Conservation =====

=== In xanthomonads ===

Yes (//e.g. Xanthomonas campestris pv. campestris// (Potnis //et al//., 2012), //Xanthomonas arboricola //pv. //corylina // (Hajri //et al//., 2012), //Xanthomonas euvesicatoria // (White and Jones 2018)).
=== In other plant pathogens/symbionts ===

Unknown.

===== References =====

Blüher D, Laha D, Thieme S, Hofer A, Eschen-Lippold L, Masch A, Balcke G, Pavlovic I, Nagel O, Schonsky A, Hinkelmann R, Wörner J, Parvin N, Greiner R, Weber S, Tissier A, Schutkowski M, Lee J, Jessen H, Schaaf G, Bonas U (2017). A 1-phytase type III effector interferes with plant hormone signaling. Nat. Commun. 8: 2159. DOI: [[http://dx.doi.org/10.1038/s41467-017-02195-8|10.1038/s41467-017-02195-8]]

Gurlebeck D, Thieme, F, Bonas U (2006). Type III effector proteins from the plant pathogen //Xanthomonas //and their role in the interaction with the host plant. J. Plant Physiol. 163: 233–255. DOI: [[https://doi.org/10.1016/j.jplph.2005.11.011|10.1016/j.jplph.2005.11.011]]

Hajri A, Pothier JF, Fischer-Le Saux M, Bonneau S, Poussier S, Boureau T, Duffy B, Manceau C (2011). Type three effector gene distribution and sequence analysis provide new insights into the pathogenicity of plant-pathogenic //Xanthomonas arboricola//. Appl Environ Microbiol. 78: 371-384. DOI: [[http://doi.org/10.1128/AEM.06119-11|10.1128/AEM.06119-11]]

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: [[https://doi.org/10.1094/MPMI-07-16-0137-R|10.1094/mpmi-07-16-0137-r]]

Potnis N, Minsavage G, Smith J K, Hurlbert J C, Norman D, Rodrigues R, Stall R E, Jones JB (2012). Avirulence proteins AvrBs7 from //Xanthomonas gardneri// and AvrBs1.1 from //Xanthomonas euvesicatoria// contribute to a novel gene-for-gene interaction in Pepper. Mol. Plant Microbe Interact. 25: 307-320. DOI: [[http://doi.org/10.1094/MPMI-08-11-0205|10.1094/MPMI-08-11-0205]]

Ronald PC, Staskawicz BJ (1988). The avirulence gene AvrBs1 from //Xanthomonas campestris //pv. //vesicatoria// encodes a 50-KD protein. Mol. Plant Microbe Interact. 1: 191-198.

White FF, Potnis N, Jones JB, Koebnik R (2009). The type III effectors of //Xanthomonas//. Mol. Plant Pathol. 10: 749-766. DOI: [[http://doi.org/10.1111/J.1364-3703.2009.00590.X|10.1111/J.1364-3703.2009.00590.X]]

White FF, Jones JB (2018). One effector at a time. Nature Plants 4: 134-135. DOI: [[https://www.nature.com/articles/s41477-018-0114-0|10.1038/s41477-018-0114-0]]

===== Further reading =====

Thieme F (2006). Genombasierte Identifizierung neuer potentieller Virulenzfaktoren von //Xanthomonas// //campestris// pv. //vesicatoria//. Doctoral Thesis, Martin-Luther-Universität Halle-Wittenberg, Germany. PDF: [[http://sundoc.bibliothek.uni-halle.de/diss-online/06/06H103/prom.pdf|http://sundoc.bibliothek.uni-halle.de/diss-online/06/06H103/prom.pdf]]

Thieme F, Koebnik R, Bekel T, Berger C, Boch J, Büttner D, Caldana C, Gaigalat L, Goesmann A, Kay S, Kirchner O, Lanz C, Linke B, McHardy AC, Meyer F, Mittenhuber G, Nies DH, Niesbach-Klösgen U, Patschkowski T, Rückert C, Rupp O, Schneiker S, Schuster SC, Vorhölter FJ, Weber E, Pühler A, Bonas U, Bartels D, Kaiser O (2005). Insights into genome plasticity and pathogenicity of the plant pathogenic bacterium //Xanthomonas campestris// pv. //vesicatoria// revealed by the complete genome sequence. J. Bacteriol. 187: 7254-7266. DOI: [[https://doi.org/10.1128/JB.187.21.7254-7266.2005|10.1128/JB.187.21.7254-7266.2005]]

===== Acknowledgements =====

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