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Molecular Diagnosis and Diversity for Regulated Xanthomonas
Bacterial virulence factors
This DokuWiki is based upon work from COST Action CA16107 EuroXanth, supported by COST (European Cooperation in Science and Technology)
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Author: Naama Wagner
Internal reviewer: Ralf Koebnik
Class: XopBH
Family: XopBH
Prototype: XTG_RS02340 (Xanthomonas euroxanthea, strain CPBF 424) Attention: The prototype sequence is too long because codons 18 to 39 overlap with the plant-inducible promoter (see below; Koebnik et al., 2006).
GenBank ID: CAJ22212.1 (286 aa)
RefSeq ID: WP_039417318.1 (216 aa)
3D structure: Unknown
XopBH was discovered by a Effectidor II, a pan-genomic AI-based algorithm for the prediction of type III secretion system effectors (Wagner et al., 2025).
A chimeric protein consisting of a C-terminally truncated XopB where the last 52 residues (5 kDa) were replaced by the triple c-myc epitope (5 kDa) was secreted into culture supernatants of a strain with a constitutively active form of hrpG in a type III secretion-dependent manner (Noël et al., 2001). XopB belongs to translocation class B (Schulze et al., 2012). Mutation studies of a putative translocation motif (TrM) showed that the proline/arginine-rich motif is required for efficient type III-dependent secretion and translocation of XopB and determines the dependence of XopB transport on the general T3S chaperone HpaB (Prochaska et al., 2018).
The presence of a PIP box and a properly spaced ‐10 promoter motif (TTCGB‐N15 ‐TTCGB‐N30–32 ‐YANNNT) suggests that the xopBH gene is under control of HrpG and HrpX (Wengelnik & Bonas, 1996; Wengelnik et al., 1996; Koebnik et al., 2006).
Unknown.
Unknown.
Unknown.
Unknown.
Yes (e.g., X. fragariae, X. cynarae pv. gardneri (syn. X. gardneri), X. oryzae, X. vasicola) (Harrison et al., 2014).
Yes (e.g., Pseudomonas spp., Ralstonia solanacearum, Acidovorax spp., Pantoea agglomerans) (Schulze et al., 2012).
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
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, in press. DOI: 10.1093/bioinformatics/btaf272
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: 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: 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: 10.1007/s11274-012-1229-5
This fact sheet is based upon work from COST Action CA16107 EuroXanth, supported by COST (European Cooperation in Science and Technology).
