EuroXanth DokuWiki

This is an old revision of the document!

Author: Jose Gadea

Class:XopAQ
Family:XopAQ
Prototype: XopAQ (X. gardneri (Xg) strain 101 (ATCC 19865).
GenBank ID: EGD19295.1 (95 aa)
3D structure: Unknown

Biological function

How discovered? XopAQ was discovered by sequencing the genome of the X. gardneri (Xg) strain 101 (8).

(Experimental) evidence for being a T3E: A functional screen to isolate Ralstonia solanacearum genes encoding proteins translocated into plant cells reveal that the gene Rip6 and Rip11 were two new translocated proteins. XopAQ is 60% identical at the protein level to these two proteins. BlastP alignment between XopAQ and Rip6 indicates that the homology is spanned along the whole protein, including the N-terminal part, suggesting that the functional motif that drives translocation in Rip6 is conserved in XopAQ. Translocation assays using a strain deleted in the hpaB gene of Ralstonia indicates that Rip6 and Rip11 requires HpaB for their effective translocation into plant cells via the Hrp T3SS (12). However, no functional translocation assay has been performed for Xanthomonas XopAQ effector to our knowledge.

Regulation: XopAQ is up-regulated when X.citri pv. citri 306 and X.citri pv. citri Aw12879 (restricted to Mexican lime) are grown in XVM2 medium, known to induce hrp gene expression, as compared with nutrient broth (NB). However, no differential expression was observed in this gene among these two strains. (9).

The X. arboricola gene shows a putative plant-inducible promoter box (PIP-BOX) sequence, 67 bp upstream of the TATA box (13).

Phenotypes:Unknown

Localization: CSS-Palm suite reveals potential myristoylation/palmitoylation motifs for XopAQ, suggesting that the protein could be targeted to the cytoplasmic membrane (11). This targeting is facilitated by a simple sequence motif at the N terminus of the polypeptide chain.

Enzymatic function: Unknown. No known motifs are found in the Rip6 and Rip11 proteins of Ralstonia (12). No motifs are found in the X. gardneri protein neither (Prosite analysis).

Interaction partners:Unknown

Conservation

In xanthomonads: Yes. Widely present in the most agressive citrus canker-causing X.citri A strains but also in the AW strain (narrow host range) (1,5), and also in the milder X. fuscans B strain, but not in the X. fuscans C strain (restricted to C. aurantifoli). (2). Present in Xanthomonas gardneri but not in some strains of X. perforans nor X. euvesicatoria strains affecting pepper and tomato (3, 8, 10). Two paralogs of XopAQ present in Strains 66b and LMG 918 of X. euvesicatoria, but not present in other LMG strains, 83b, 85-10, or X. euvesicatoria pv. rosa (11). Present in pathogenic (but not in non-pathogenic) X. arboricola pv. pruni (5, 7), but not in the related X. juglandis or X. corylina (6) Also present in X. citri pv. viticola (3) and other X, citri pathovars (blastp analysis). X. phaseolis and X. populi, among others, present a protein with moderate homology in a blastp analysis.

In other plant pathogens/symbionts:Yes (Ralstonia).

References

1. Escalon A, Javegny S, Vernière C, Noël LD, Vital K, Poussier S, Hajri A, Boureau T, Pruvost O, Arlat M, Gagnevin L. Variations in type III effector repertoires, pathological phenotypes and host range of Xanthomonas citri pv. citri pathotypes. Mol Plant Pathol. 2013 Jun;14(5):483-96. doi:10.1111/mpp.12019.
2. Dalio RJD, Magalhães DM, Rodrigues CM, Arena GD, Oliveira TS, Souza-Neto RR, Picchi SC, Martins PMM, Santos PJC, Maximo HJ, Pacheco IS, De Souza AA, Machado MA. PAMPs, PRRs, effectors and R-genes associated with citrus-pathogen interactions. Ann Bot. 2017 Mar 1;119(5):749-774. doi: 10.1093/aob/mcw238.
3. Schwartz AR, Potnis N, Timilsina S, Wilson M, Patané J, Martins J Jr,Minsavage GV, Dahlbeck D, Akhunova A, Almeida N, Vallad GE, Barak JD, White FF, Miller SA, Ritchie D, Goss E, Bart RS, Setubal JC, Jones JB, Staskawicz BJ. Phylogenomics of Xanthomonas field strains infecting pepper and tomato reveals diversity in effector repertoires and identifies determinants of host specificity. Front Microbiol. 2015 Jun 3;6:535. doi: 10.3389/fmicb.2015.00535.
4. Ferreira MASV, Bonneau S, Briand M, Cesbron S, Portier P, Darrasse A, Gama MAS, Barbosa MAG, Mariano RLR, Souza EB, Jacques MA. Xanthomonas citri pv. viticola Affecting Grapevine in Brazil: Emergence of a Successful Monomorphic Pathogen. Front Plant Sci. 2019 Apr 18;10:489. doi: 10.3389/fpls.2019.00489.
5. Garita-Cambronero J, Sena-Vélez M, Ferragud E, Sabuquillo P, Redondo C, Cubero J. Xanthomonas citri subsp. citri and Xanthomonas arboricola pv. pruni: Comparative analysis of two pathogens producing similar symptoms in different host plants. PLoS One. 2019 Jul 18;14(7):e0219797. doi: 10.1371/journal.pone.0219797.
6. Garita-Cambronero J, Palacio-Bielsa A, Cubero J. Xanthomonas arboricola pv. pruni, causal agent of bacterial spot of stone fruits and almond: its genomic and phenotypic characteristics in the X. arboricola species context. Mol Plant Pathol. 2018 Sep;19(9):2053-2065. doi: 10.1111/mpp.12679.
7. Garita-Cambronero J, Palacio-Bielsa A, López MM, Cubero J. Comparative Genomic and Phenotypic Characterization of Pathogenic and Non-Pathogenic Strains of Xanthomonas arboricola Reveals Insights into the Infection Process of Bacterial Spot Disease of Stone Fruits. PLoS One. 2016 Aug 29;11(8):e0161977. doi: 10.1371/journal.pone.0161977.
8. Potnis N, Krasileva K, Chow V, Almeida NF, Patil PB, Ryan RP, Sharlach M, Behlau F, Dow JM, Momol M, White FF, Preston JF, Vinatzer BA, Koebnik R, Setubal JC, Norman DJ, Staskawicz BJ, Jones JB. Comparative genomics reveals diversity among xanthomonads infecting tomato and pepper. BMC Genomics. 2011 Mar 11;12:146. doi: 10.1186/1471-2164-12-146.
9. Jalan N, Kumar D, Andrade MO, Yu F, Jones JB, Graham JH, White FF, Setubal JC,Wang N. Comparative genomic and transcriptome analyses of pathotypes of Xanthomonas citri subsp. citri provide insights into mechanisms of bacterial virulence and host range. BMC Genomics. 2013 Aug 14;14:551. doi: 10.1186/1471-2164-14-551.
10. Jibrin MO, Potnis N, Timilsina S, Minsavage GV, Vallad GE, Roberts PD, Jones JB, Goss EM. Genomic Inference of Recombination-Mediated Evolution in Xanthomonas euvesicatoria and X. perforans. Appl Environ Microbiol. 2018 Jun 18;84(13). pii: e00136-18. doi: 10.1128/AEM.00136-18.
11. Barak JD, Vancheva T, Lefeuvre P, Jones JB, Timilsina S, Minsavage GV, Vallad GE, Koebnik R. Whole-Genome Sequences of Xanthomonas euvesicatoria Strains Clarify Taxonomy and Reveal a Stepwise Erosion of Type 3 Effectors. Front Plant Sci. 2016 Dec 9;7:1805. doi: 10.3389/fpls.2016.01805.
12. Mukaihara T, Tamura N, Iwabuchi M. Genome-wide identification of a large repertoire of Ralstonia solanacearum type III effector proteins by a new functional screen. Mol Plant Microbe Interact. 2010 Mar;23(3):251-62. doi:10.1094/MPMI-23-3-0251.
13. Garita-Cambronero J. Doctoral Thesis. Genómica comparativa de cepas de Xanthomonas arborícola asociadas a Prunus ssp. Caracterización de los procesos de infección de la mancha bacteriana de frutales de hueso y almendro. 2016. Universidad Politécnica de Madrid.