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

Author: [[https://www.researchgate.net/profile/Ralf_Koebnik|Ralf Koebnik]]\\
Internal reviewer: Anna Passelergue

Class: XopW\\
Families: XopW1, XopW2, XopW3, XopW4, XopW5\\
Prototype: XOO0037 (XopW1) (//Xanthomonas oryzae// pv. //oryzae//; strain T7174), G4Q83_RS22690 (XopW2) (//Xanthomonas theicola//; strain CFBP 4691), AB8814_02550 (XopW3) (//Xanthomonas hydrangeae//; strain NCPPB 4692), LYZ81_10440 (XopW4) (//Xanthomonas hortorum//; strain BP5178), C8F00_2046 (XopW5) (//Xanthomonas vasicola//; strain BLS185)\\
GenBank ID: XopW1[[https://www.ncbi.nlm.nih.gov/protein/BAE66792.1|BAE66792.1]] (204 aa), XopW2[[https://www.ncbi.nlm.nih.gov/protein/QNH27166.1|QNH27166.1]] (85 aa), XopW3[[https://www.ncbi.nlm.nih.gov/protein/XDZ21859.1|XDZ21859.1]] (196 aa), XopW4[[https://www.ncbi.nlm.nih.gov/protein/MCE4362839.1|MCE4362839.1]] (227 aa), XopW5[[https://www.ncbi.nlm.nih.gov/protein/TCK49608.1|TCK49608.1]] (228 aa)\\
RefSeq ID: XopW1[[https://www.ncbi.nlm.nih.gov/protein/WP_228329674.1|WP_228329674.1]] (203 aa), XopW2[[https://www.ncbi.nlm.nih.gov/protein/WP_211288317.1|WP_211288317.1]] (176 aa), XopW3[[https://www.ncbi.nlm.nih.gov/protein/WP_205393482.1|WP_205393482.1]] (196 aa), XopW4[[https://www.ncbi.nlm.nih.gov/protein/WP_233380913.1|WP_233380913.1]] (227 aa), XopW5[[https://www.ncbi.nlm.nih.gov/protein/WP_230597584.1|WP_230597584.1]] (228 aa)\\
3D structure: Unknown

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

=== How discovered? ===

XopW1 was discovered via genome-wide screening for effector candidates in //X. oryzae// pv. //oryzae// (//Xoo//) strain MAFF 311018 in accordance with three criteria: i) ORF encoding proteins homologous to effectors of //P. syringae// strains and //X. campestris// pv. //vesicatoria//, ii) HrpX regulons preceded by two cis elements (Plant Induced Promoter, PIP; and -10 box-like motif) or iii) proteins with an N-terminal amino acid composition similar to known effectors (more than 10% of Ser in the first 50 amino aa, no Asp or Glu residues in the first 12 aa, and an aliphatic amino acid or Pro at the third or fourth position) (Furutani //et al//., 2009).

XopW2 was discovered as an ORF that is encoded downstream of a PIP box and a properly spaced ‐10 promoter motif (TTCGB‐N<sub>15</sub> ‐TTCGB‐N<sub>30-32</sub> ‐YANNNT) (Passelergue, 2025).
=== (Experimental) evidence for being a T3E ===

TT3S-dependent translocation of XopW1 has been shown by a calmodulin-dependent adenylate cyclase reporter assay (Furutani //et al//., 2009). XopW1 and XopW2 were confirmed/shown to have a functional type III secretion signal using a reporter fusion with AvrBs1 (Zhao //et al.//, 2013; Passelergue, 2025).
=== Regulation ===

The presence of a PIP box and a properly spaced ‐10 promoter motif (TTCGB‐N<sub>15</sub> ‐TTCGB‐N<sub>30–32</sub> ‐YANNNT) suggests that the //xopW2// gene is under control of HrpG and HrpX (Wengelnik & Bonas, 1996; Wengelnik //et al.//, 1996; Koebnik //et al.//, 2006).
=== Phenotypes ===

Unknown.

=== Localization ===

Unknown.

=== Enzymatic function ===

Unknown.

=== Interaction partners ===

Unknown.

===== Conservation =====

=== In xanthomonads ===

XopW1: Yes (//e.g.//, //X. oryzae//, //X.prunicola//, //X. euvesicatoria, X. axonopodis// pv. //nakataecorchori//)\\
XopW2: Yes (//e.g.//, //X. theicola//)\\
XopW3: Yes (//e.g.//, //X. hydrangeae//, //X. arboricola//, //X. populi//)\\
XopW4: Yes (//e.g.//, //X. hortorum//, //X. campestris// pv. //badrii//)\\
XopW5: Yes (//e.g.//, //X. vasicola//)
=== In other plant pathogens/symbionts ===

XopW1: No\\
XopW2: Remote homolog in //Ralstonia// ssp. (Effector candidate Rs_T3E_Hyp7)\\
XopW3: Remote homolog in //Ralstonia// ssp. (Effector candidate Rs_T3E_Hyp7)\\
XopW4: No\\
XopW5: No

===== References =====

Furutani A, Takaoka M, Sanada H, Noguchi Y, Oku T, Tsuno K, Ochiai H, Tsuge S (2009). Identification of novel type III secretion effectors in //Xanthomonas oryzae// pv. //oryzae//. Mol. Plant Microbe Interact. 22: 96-106. DOI: [[https://doi.org/10.1094/MPMI-22-1-0096|10.1094/MPMI-22-1-0096]]

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: [[https://doi.org/10.1128/JB.00795-06|10.1128/JB.00795-06]]

Passelergue A (2025). Discovery of eight type III effector genes harboring the PIP box in clade-I xanthomonads. Master's thesis, Université de Montpellier, France.

Wengelnik K, Bonas U (1996). HrpXv, an AraC-type regulator, activates expression of five of the six loci in the hrp cluster of //Xanthomonas campestris// pv. //vesicatoria//. J. Bacteriol. 178: 3462-3469. DOI: [[https://doi.org/10.1128/jb.178.12.3462-3469.1996|10.1128/jb.178.12.3462-3469.1996]]

Wengelnik K, Van den Ackerveken G, Bonas U (1996). HrpG, a key hrp regulatory protein of //Xanthomonas campestris// pv. //vesicatoria// is homologous to two-component response regulators. Mol. Plant Microbe Interact. 9: 704-712. DOI: [[https://doi.org/10.1094/mpmi-9-0704|10.1094/mpmi-9-0704]]

Zhao S, Mo WL, Wu F, Tang W, Tang JL, Szurek B, Verdier V, Koebnik R, Feng JX (2013). Identification of non-TAL effectors in //Xanthomonas oryzae// pv. //oryzae// Chinese strain 13751 and analysis of their role in the bacterial virulence. World J. Microbiol. Biotechnol. 29: 733-744. DOI: [[https://doi.org/10.1007/s11274-012-1229-5|10.1007/s11274-012-1229-5]]

===== Acknowledgements =====

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