The Type III Effector XopV from //Xanthomonas//

Author: Coline Sciallano
Internal reviewer: Gábor Rákheli
Expert reviewer: Seiji Tsuge

Class: XopV
Family: XopV
Prototype: XOO3803 (Xanthomonas oryzae pv. oryzae; strain T7174)
GenBank ID: BAE70558.1 (331 aa)
RefSeq ID: WP_011409498.1 (331 aa)
3D structure: Unknown

XopV was discovered via genome-wide screening for effector candidates in X. oryzae pv. oryzae (Xoo) strain MAFF 311018 in accordance with three criteria: i) ORF encoding proteins homologous to effectors of P. syringae strains and X. campestris pv. vesicatoria, ii) HrpX regulons preceded by two cis elements (Plant Induced Promoter, PIP; and -10 box-like motif) or iii) proteins with an N-terminal amino acid composition similar to known effectors (more than 10% of Ser in the first 50 amino aa, no Asp or Glu residues in the first 12 aa, and an aliphatic amino acid or Pro at the third or fourth position) (Furutani et al., 2009).

TT3S-dependent translocation of XopV has been shown by a calmodulin-dependent adenylate cyclase reporter assay (Furutani et al., 2009).

xopV was shown to contain the PIP-box motif in their promoter region, and the expression was found to be regulated by HrpX using a β -glucuronidase (GUS) reporter assay in hrp-inducing medium (Tsuge et al., 2005).

Popov et al. (2016) reported that Xanthomonas euvesicatoria XopV inhibits flg22-triggered immunity in Arabidopsis thaliana using apathogen-free cell system for transient gene expression analysis. An individual mutant for xopV in Xoo PXO99^A did not show reduced virulence on rice varieties IR24 (Song & Yang, 2010) and Kitaake (Long et al., 2018). But interestingly, a significant reduction in lesion length on Kitaake was observed when inoculated with a triple mutant of PXO99^A for xopV, xopZ (two copies) and xopN although no differences in virulence were observed when comparing the WT PXO99^A strain and individual or double mutants for each of these effector genes (xopV, xopZ, xopN). Three effectors were shown to be able to suppress the peptidoglycan-triggered MAPK activation when individually expressed in rice cells.The results indicate that XopV, along with XopZ and XopN, collectively and redundantly contributes virulence in rice (Long et al., 2018) . Agrobacterium-mediated transient expression of both XopQ and XopX in rice cells resulted in induction of rice immune responses, which were not observed when either protein was individually expressed. Five effectors, XopV, XopU, XopP, XopG and AvrBs2, could individually suppress these immune responses, which suggests a complex interplay of Xanthomonas effectors in suppression of not only pathogen-triggered immunity but also effector-triggered immunity to promote virulence on rice (Deb et al., 2020).

Unknown.

Unknown.

Unknown.

Yes, examples: X. campestris, X. euvesicatoria, X. oryzae, X. vasicola, X. phaseoli, X. citri, X. axonopodis.

Yes, examples: Pseudomonas cissicola, Ralstonia solanacearum, Acidovorax citrulli.

Deb S, Ghosh P, Patel HK, Sonti RV (2020). Interaction of the Xanthomonas effectors XopQ and XopX results in induction of rice immune responses. Plant J. 104: 332-350. DOI: 10.1111/tpj.14924

Furutani A, Takaoka M, Sanada H, Noguchi Y, Oku T, Tsuno K, Tsuge S (2009). Identification of novel type III secretion effectors in Xanthomonas oryzae pv. oryzae. Mol. Plant Microbe Interact. 22: 96-106. DOI: 10.1094/mpmi-22-1-0096

Long J, Song C, Yan F, Zhou J, Zhou H, Yang B (2018). Non-TAL effectors from Xanthomonas oryzae pv. oryzae suppress peptidoglycan-triggered MAPK activation in rice. Front. Plant Sci. 12: 1857. DOI: 10.3389/fpls.2018.01857

Popov G, Fraiture M, Brunner B, Sessa G (2016). Multiple Xanthomonas euvesicatoria type III effectors inhibit flg22-triggered immunity. Mol. Plant Microbe Interact. 29:651–660. DOI:10.1094/MPMI-07-16-0137-R

Song C, Yang B (2010). Mutagenesis of 18 type III effectors reveals virulence function of XopZ_PXO99 in Xanthomonas oryzae pv. oryzae. Mol. Plant Microbe Interact. 23: 893-902. DOI: 10.1094/mpmi-23-7-0893 Tsuge S, Terashima S, Furutani A, Ochiai H, Oku T, Tsuno K, Kaku H, Kubo Y (2005). Effects on promoter activity of base substitutions in the cis-acting regulatory element of HrpXo regulons in Xanthomonas oryzae pv. oryzae. J. Bacteriology 187: 2308-2314. DOI: 10.1128/JB.187.7.2308-2314.2005

This fact sheet is based upon work from COST Action CA16107 EuroXanth, supported by COST (European Cooperation in Science and Technology).