Author: Jaime Cubero
Internal reviewer: Ralf Koebnik
Expert reviewer:

Class: XopE
Family: XopE1
Prototype: XCV0294 (Xanthomonas euvesicatoria pv. euvesicatoria aka Xanthomonas campestris pv. vescicatoria; strain 85-10)
RefSeq ID: CAJ21925.1 (400 aa)
Synonym: AvrXacE1 (Xanthomonas citri pv. citri)
3D structure: Myr motif at their extreme N-terminus.

XopE1 was first identified by sequence homology searches (da Silva et al., 2002; Thieme et al., 2005).

XopE1 fused to the AvrBs3 reporter, was shown to translocate into plant cells in an hrpF-dependent manner (Thieme et al., 2007).

XopE1 from X. euvesicatoria was found to be regulated by HrpG and HrpX (Thieme et al., 2007), its promoter contains a PIP BOX and it is coregulated with the T3 secretion machinery.

Agrobacterium-mediated expression of XopE1 triggers a fast cell-death reaction in non host Nicotiana plants revealing that XopE1 is recognized by Nicotiana. Its membrane localization delays the detection by the plant surveillance system and contribute to inactivate plant immune responses (Thieme et al., 2007). XopE1 was associated to different grades of citotoxicity and intermediate growth inhibition on yeast and cause phenotypes ranging from chlorosis to cell death when transiently expressed via Agrobacterium spp. in either host or non host plants (Salomon et al., 2011; Adlung et al., 2016). XopE1 mutants grow to equivalent titers as wild type X. euvesicatoria in tomato leaves indicating that is not required for bacterial multiplication in planta. XopE1 however is required to suppress chlorosis and tissue collapse at very late stages of Xanthomonas infection. XopE1 together with XopE2 and XopO may function redundantly to inhibit X. euvesicatoria induced chlorosis in tomato leaves (Dubrow et al., 2018).

XopE1 fused to gfp in a binary vector under control of the Cauliflower mosaic virus 35S promoter expressed in Nicotiana Benthamiana leaves, using Agrobacterium-mediated gene transfer, allowed to localize XopE1::GFP confined to the periphery of the cells being not detectable in the nucleus or in the cytoplasm.

XopE1 belongs to the HopX effector family, which are part of the transglutaminase superfamily (Nichmuk et al., 2007).

XopE1 was found to physically interact with tomato 14-3-3s (TFT) and is also associated to VirK secreted by T2SS and with a possible role in the modulation of plant immune response during the infection process (Assis et al., 2017).

Yes (e.g., X. citri, X. campestris, X. phaseoli, X. alfalfa, X. euvesicatoria).

Yes (Pseudomonas, Ralstonia).

Adlung N, Prochaska H, Thieme S, Banik A, Blüher D, John P, Nagel O, Schulze S, Gantner J, Delker C, Stuttmann J, Bonas U (2016). Non-host resistance induced by the Xanthomonas effector XopQ is widespread within the genus Nicotiana and functionally depends on EDS1. Front. Plant Sci. 7: 1796. DOI: 10.3389/fpls.2016.01796

Assis RAB, Polloni LC, Patané JSL, Thakur S, Felestrino ÉB, Diaz-Caballero J, Digiampietri LA, Goulart LR, Almeida NF, Nascimento R, Dandekar AM, Zaini PA, Setubal JC, Guttman DS, Moreira LM (2017). Identification and analysis of seven effector protein families with different adaptive and evolutionary histories in plant-associated members of the Xanthomonadaceae. Sci. Rep. 7:16133. DOI: 10.1038/s41598-017-16325-1

da Silva AC, Ferro JA, Reinach FC, Farah CS, Furlan LR, Quaggio RB, Monteiro-Vitorello CB, Van Sluys MA, Almeida NF, Alves LM, do Amaral AM, Bertolini MC, Camargo LE, Camarotte G, Cannavan F, Cardozo J, Chambergo F, Ciapina LP, Cicarelli RM, Coutinho LL, Cursino-Santos JR, El Dorry H, Faria JB, Ferreira AJ, Ferreira RC, Ferro MI, Formighieri EF, Franco MC, Greggio CC, Gruber A, Katsuyama AM, Kishi LT, Leite RP, Lemos EG, Lemos MV, Locali EC, Machado MA, Madeira AM, Martinez-Rossi NM, Martins EC, Meidanis J, Menck CF, Miyaki CY, Moon DH, Moreira LM, Novo MT, Okura VK, Oliveira, MC, Oliveira VR, Pereira HA, Rossi A, Sena JA, Silva C, de Souza RF, Spinola LA,Takita MA, Tamura RE, Teixeira EC, Tezza RI, Trindade dos SM, Truffi D, Tsai, SM, White FF, Setubal JC, Kitajima JP (2002). Comparison of the genomes of two Xanthomonas pathogens with differing host specificities. Nature 417: 459-463. DOI: 10.1038/417459a

Dubrow Z, Sunitha S, Kim JG, Aakre CD, Girija AM, Sobol G, Teper D, Chen YC, Ozbaki-Yagan N, Vance H, Sessa G, Mudgett MB (2018). Tomato 14-3-3 proteins are required for Xv3 disease resistance and interact with a subset of Xanthomonas euvesicatoria effectors. Mol. Plant Microbe Interact. 31: 1301-1311. DOI: 10.1094/MPMI-02-18-0048-R

Nimchuk ZL, Fisher EJ, Desvaux D, Chang JH, Dangl JL (2007). The HopX (AvrPphE) family of Pseudomonas syringae type III effectors require a catalytic triad and a novel N-terminal domain forfunction. Mol. Plant Microbe Interact. 20: 346-357. DOI: 10.1094/MPMI-20-4-0346

Salomon D, Dar D, Sreeramulu S, Sessa G (2011). Expression of Xanthomonas campestris pv. vesicatoria type III effectors in yeast affects cell growth and viability. Mol Plant Microbe Interact. 24: 305-314. DOI: 0.1094/MPMI-09-10-0196

Thieme F, Koebnik R, Bekel T, Berger C, Boch J, Büttner D, Caldana C, Gaigalat L, Goesmann A, Kay S, Kirchner O, Lanz C, Linke B, McHardy AC, Meyer F, Mittenhuber G, Nies DH, Niesbach-Klösgen U, Patschkowski T, Rückert C, Rupp O, Schneiker S, Schuster SC, Vorhölter F, Weber E, Pühler A, Bonas U, Bartels D, Kaiser O (2005). Insights into genome plasticity and pathogenicity of the plant pathogenic bacterium Xanthomonas campestris pv. vesicatoria revealed by the complete genome sequence. J. Bacteriol. 187: 7254-7266. DOI: 10.1128/JB.187.21.7254-7266.2005

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: 10.1094/MPMI-20-10-1250