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--- bacteria:t3e:xopah [2025/01/29 23:11] – [Biological function] jfpothier
+++ bacteria:t3e:xopah [2025/08/04 09:40] (current) – [The Type III Effector XopAH from //Xanthomonas//] rkoebnik
@@ Line 2: / Line 2: @@
 Author: [[https://www.researchgate.net/profile/Steven_Roberts8|Steven J. Roberts]]\\
-Internal reviewer: [[https://www.researchgate.net/profile/Christian_Verniere|Christian Vernière ]]
+Internal reviewer: [[https://www.researchgate.net/profile/Christian_Verniere|Christian Vernière]], Anna Passelergue\\
+Expert reviewer: [[https://www.researchgate.net/profile/Ralf_Koebnik|Ralf Koebnik]]
 Class: XopAH\\
@@ Line 16: / Line 17: @@
 === How discovered? ===
-AvrXccC was described during a genome comparison analysis between //Xanthomonas citri// pv. citri and //X. campestris// pv. campestris Xcc strain ATCC 33913 = NCPPB 528 (Da Silva et al., 2002) and in a search of annotated genome (Castenada //et al//., 2005).
+AvrXccC was described during a genome comparison analysis between //Xanthomonas citri// pv. //citri// strain 306 and //X. campestris// pv. //campestris// strain ATCC 33913 = NCPPB 528 (Da Silva et al., 2002) and in a search of annotated genomes (Castenada //et al//., 2005).
+The homolog in //Xanthomonas hyacinthi// strain CFBP 1156 (FZ025_RS19665) 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). Remark: The ORF of locus FZ025_RS19665 probably lacks 88 codons at the N terminus, as suggested by a shorter distance to the ‐10 promoter motif and the presence of a Shine-Dalgarno sequence (AGGAG). This conclusion is also supported by the presence of conserved myristoylation and palmitoylation signals at the N terminus when the ORF is extended by 88 codons at the N terminus (Nimchuk //et al.//, 2000; Thieme //et al.//, 2007). The protein was also predicted as a type III effector by [[https://effectidor.tau.ac.il/|Effectidor II]], a pan-genomic AI-based algorithm for the prediction of type III secretion system effectors (Wagner //et al.//, 2025).
 === (Experimental) evidence for being a T3E ===
 Secreted XopAH (AvrXccC) proteins were detected in culture fluid from //Xcc// 8004 and //hrcV// mutant complemented strains but not from the //hrcV// mutant (Wang //et al//., 2007). Insertion and deletion mutants affecting the locus (Xcc2109) in the type strain (Xcc 528) resulted in loss of virulence on the host Florida Broad Leaf Mustard (Castañeda //et al//., 2005).
+The homolog in //X. hyacinthi// strain CFBP 1156 (FZ025_RS19665), including the typical N-terminal palmitoylation signal (MGLC), was shown to have a functional type III secretion signal using a reporter fusion with AvrBs1 (Zhao //et al.//, 2013; Passelergue, 2025).
 === Regulation ===
 Promoter activity assays showed that the expression of XopAH (//avrXccC//) is //hrpG/hrpX//-dependent (Wang //et al//., 2007).
+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 //xopAH// gene of //X. hyacinthi// strain CFBP 1156 (FZ025_RS19665) is under control of HrpG and HrpX (Wengelnik & Bonas, 1996; Wengelnik //et al.//, 1996; Koebnik //et al.//, 2006).
 === Phenotypes ===
-This effector is required for full virulence in the susceptible host cabbage (//Brassica oleracea//) (Wang //et al//., 2007) and results in avirulence in the resistant host mustard (//Brassica napiformis//) (Castaneda //et al//., 2005; He //et al//., 2007; Wang //et al//., 2007). The intact AvrB-AvrC domain of //AvrXccC<sub>8004</sub>// is essential and sufficient to elicit defense responses in an //Arabidopsis// resistant ecotype (Col-0) (Ho //et al//., 2013).
+AvrXccC is required for full virulence in the susceptible host cabbage (//Brassica oleracea//) (Wang //et al//., 2007) and results in avirulence in the resistant host mustard (//Brassica napiformis//) (Castaneda //et al//., 2005; He //et al//., 2007; Wang //et al//., 2007). The intact AvrB-AvrC domain of //AvrXccC<sub>8004</sub> // is essential and sufficient to elicit defense responses in an //Arabidopsis// resistant ecotype (Col-0) (Ho //et al//., 2013).
-In the interaction //Arabidopsis// / //Xcc// strain 8004, //AvrXccC<sub>8004</sub> // not only presented its avirulence activity to trigger plant defense response but also possessed its virulence activity to manipulate the component involved in the ABA signalling pathway leading to an increase of ABA concentrations (Ho //et al//., 2013).
+In the interaction //Arabidopsis// / //Xcc// strain 8004, AvrXccC<sub>8004</sub> not only presented its avirulence activity to trigger plant defense response but also possessed its virulence activity to manipulate the component involved in the ABA signalling pathway leading to an increase of ABA concentrations (Ho //et al.//, 2013).
 === Localization ===
-XopAH (AvrXccC) is anchored to the plant plasma membrane, and the N‐terminal myristoylation site (amino acids 2–7: GLcaSK) is essential for its localization (Wang //et al//., 2007).
+XopAH (AvrXccC) is anchored to the plant plasma membrane, and the N‐terminal myristoylation site (amino acids 2–7: GLcaSK) is essential for its localization (Wang //et al.//, 2007).
+The presence of conserved myristoylation and palmitoylation signals at the N terminus of XopAH (FZ025_RS19665) suggests again that the protein is localized to the plasma membrane in the plant host cell (Nimchuk //et al.//, 2000; Thieme //et al.//, 2007).
 === Enzymatic function ===
-XopAH has a Fido/AvrB domain derived from the fic (cyclic adenosine monophosphate (cAMP)-induced filamentation and doc (death on curing) domains (Kinch //et al//., 2009). Structural comparisons resulted in the inclusion of similar segments of the T3 effector AvrB from //Pseudomonas syringae// species (Kinch //et al//., 2009; White //et al//., 2009). T3 effectors in the XopAH group could trans-AMPylate plant host proteins. AMPylation represents a posttranslational modification used to stably modify proteins with AMP (Kinch //et al//., 2009).
+XopAH has a Fido/AvrB domain derived from the fic (cyclic adenosine monophosphate (cAMP)-induced filamentation and doc (death on curing) domains (Kinch //et al//., 2009). Structural comparisons resulted in the inclusion of similar segments of the T3 effector AvrB from //Pseudomonas syringae// species (Kinch //et al//., 2009; White //et al//., 2009). T3 effectors in the XopAH group could trans-AMPylate plant host proteins. AMPylation represents a posttranslational modification used to stably modify proteins with AMP (Kinch //et al.//, 2009).
 === Interaction partners ===
-Not known ?
+Not known.
 ===== Conservation =====
@@ Line 48: / Line 51: @@
 === In xanthomonads ===
-In //Xanthomonas campestris// pv. campestris. XopAH is also present in //X. arboricola// pv. juglandis within strains causing Walnut Blight but is absent from the strains causing vertical oozing canker (Cesbron et al., 2015).
+In //Xanthomonas campestris// pv. campestris. XopAH is also present in //X. arboricola// pv. juglandis within strains causing walnut blight but is absent from the strains causing vertical oozing canker (Cesbron //et al.//, 2015).
+But also conserved in //X. hyacinthi//, //X. hydrangeae//, //X. axonopodis// pv. cyamopsidis, //X. hortorum//, //X. dyei//.
 === In other plant pathogens/symbionts ===
 Yes (AvrB //Pseudomonas savastanoi//, //Pseudomonas syringae//) (Lee //et al.//, 2004; Desveaux //et al.//, 2007)
+But also conserved in //Pseudomonas// spp., //Xylophilus ampelinus// and// Exilibacterium //sp//.//,
 ===== References =====
@@ Line 67: / Line 75: @@
 Kinch LN, Yarbrough ML, Orth K, Grishin NV (2009). Fido, a novel AMPylation domain common to Fic, Doc, and AvrB. PLoS One 4: e5818. DOI: [[https://doi.org/10.1371/journal.pone.0005818|10.1371/journal.pone.0005818]]
+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]]
 Lee CC, Wood MD, Ng K, Andersen CB, Liu Y, Luginbühl P, Spraggon G, Katagiri F (2004). Crystal structure of the type III effector AvrB from //Pseudomonas syringae//. Structure 12: 487-494. DOI: [[https://doi.org/10.1016/j.str.2004.02.013|10.1016/j.str.2004.02.013]]
+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.
 Qian W, Jia Y, Ren SX, He Y Q, Feng JX, Lu LF, Sun Q, Ying G, Tang DJ, Tang H, Wu W, Hao P, Wang L, Jiang BL, Zeng S, Gu WY, Lu G, Rong L, Tian Y, Yao Z, Fu G, Chen B, Fang R, Qiang B, Chen Z, Zhao GP, Tang JL, He C (2005). Comparative and functional genomic analyses of the pathogenicity of phytopathogen //Xanthomonas campestris// pv. //campestris.// Genome Res. 15: 757-767. DOI: [[https://doi.org/10.1101/gr.3378705|10.1101/gr.3378705]]
+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]]
+Wagner N, Baumer E, Lyubman I, Shimony Y, Bracha N, Martins L, Potnis N, Chang JH, Teper D, Koebnik R, Pupko T (2025). Effectidor II: a pan-genomic AI-based algorithm for the prediction of type III secretion system effectors. Bioinformatics 41: btaf272. DOI: [[https://doi.org/10.1093/bioinformatics/btaf272|10.1093/bioinformatics/btaf272]]
 Wang L, Tang X, He C (2007). The bifunctional effector AvrXccC of //Xanthomonas campestris// pv. //campestris// requires plasma membrane-anchoring for host recognition. Mol. Plant Pathol. 8: 491-501. DOI: [[https://doi.org/10.1111/j.1364-3703.2007.00409.x|10.1111/j.1364-3703.2007.00409.x]]
+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]]
 White FF, Potnis N, Jones JB, Koebnik R (2009). The type III effectors of //Xanthomonas//. Mol. Plant Pathol. 10: 749-766. DOI: [[https://doi.org/10.1111/j.1364-3703.2009.00590.x|10.1111/j.1364-3703.2009.00590.x]]
+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 =====

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