====== The Type III Effector XopJ7 from //Xanthomonas// ======

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

Class: XopJ\\
Family: XopJ7\\
Prototype: E4A48_06420 (//Xanthomonas// //cerealis// pv. //cerealis//, strain 01)\\
GenBank ID: [[https://www.ncbi.nlm.nih.gov/protein/QDI05802.1|QDI05802.1]] (493 aa)\\
RefSeq ID: [[https://www.ncbi.nlm.nih.gov/protein/WP_185910725.1|WP_185910725.1]] (389 aa). Attention: The RefSeq sequence is too short because 104 codons encoding the N-terminal region, including the type III secretion signal, are missing.\\
3D structure: Unknown

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

=== How discovered? ===

XopJ7 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). Additional evidence came from the presence of conserved myristoylation and palmitoylation signals (Nimchuk //et al.//, 2000; Thieme //et al.//, 2007), which were in frame with the ORF. Based on this observation, the translation initiation codon is likely 104 codons upstream of the annotated codon for the locus E4A48_RS06415.

=== (Experimental) evidence for being a T3E ===

XopJ7 was shown to have a functional type III secretion signal using a reporter fusion with AvrBs1 (Zhao //et al.//, 2013).

=== 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 //xopJ7// gene is under control of HrpG and HrpX (Wengelnik & Bonas, 1996; Wengelnik //et al.//, 1996; Koebnik //et al.//, 2006).

=== Phenotypes ===

Unknown.

=== Localization ===

The presence of conserved myristoylation and palmitoylation signals at the N terminus suggests that the protein is localized to the plasma membrane in the plant host cell (Nimchuk //et al.//, 2000; Thieme //et al.//, 2007).
=== Enzymatic function ===

Unknown.

=== Interaction partners ===

Unknown.

===== Conservation =====

=== In xanthomonads ===

Yes (//e.g.//, //X. euvesicatoria//, //X. campestris//, //X. hortorum//).
=
== In other plant pathogens/symbionts ===

Yes (e.g., //Acidovorax/////Paracidovorax// ssp., //Burkholderia/////Paraburkholderia// ssp; remote homologs in //Ralstonia// ssp.].

===== References =====

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]]

Nimchuk Z, Marois E, Kjemtrup S, Leister RT, Katagiri F, Dangl JL (2000). Eukaryotic fatty acylation drives plasma membrane targeting and enhances function of several type III effector proteins from //Pseudomonas syringae//. Cell 101: 353-363. DOI: [[https://doi.org/10.1016/s0092-8674(00)80846-6|10.1016/s0092-8674(00)80846-6]]

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.

Thieme F, Szczesny R, Urban A, Kirchner O, Hause G, Bonas U (2007). New type III effectors from //Xanthomonas campestris// pv. //vesicatoria// trigger plant reactions dependent on a conserved N-myristoylation motif. Mol. Plant Microbe Interact. 20: 1250-1261. DOI: [[https://doi.org/10.1094/MPMI-20-10-1250|10.1094/MPMI-20-10-1250]]

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).