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bacteria:t3e:xopai

The Type III Effector XopAI from //Xanthomonas//

Author: Ralf Koebnik
Internal reviewer:
Expert reviewer: WANTED!

Class: XopAI
Family: XopAI
Prototype: XAC3230 (Xanthomonas citri pv. citri; strain 306)
GenBank ID: AAM38074.1 (296 aa)
RefSeq ID: WP_011052119.1 (296 aa)
3D structure: 6K93, 6K94, 6KLY (Liu et al., 2019)

Biological function

How discovered?

Based on the complete genome sequence, XopAI (XAC3230) was proposed as a Hrp regulon candidate (da Silva et al., 2002).

Co-regulation of xopAI with other HrpG-controlled genes was also proposed by Noël et al. (2006) based on the observation that 200 bp of the 5' sequence including promoter and coding regions of xopE2 (avrXacE3) and xopAI (XAC3230) from X. citri pv. citri are more than 85% identical to the corresponding region of xopJ, which is a member of the HrpG regulon from X. euvesicatoria pv. euvesicatoria (ex X. campestris pv. vesicatoria).

Based on homology to effectors from Pseudomonas syringae and a strongly conserved 43‐amino‐acid N‐terminal domain that is also found in the N‐termini of effectors in class XopE and XopJ, XopAI was proposed to be a T3E (Stavrinides et al., 2006; White et al., 2009).

(Experimental) evidence for being a T3E

Unknown.

Regulation

Using microarrays, seven T3E genes from X. citri pv. citri were found to be upregulated in planta, five of which in all the three times investigated, i.e. 24 hpi, 72 hpi and 120 hpi (xopE1, xopN, xopK, xopE3, xopAI), and the two remaining at the later times of the infectious process (xopE2 and xopV) (de Laia et al., 2019).

Phenotypes

Unknown.

Localization

The XopAI N‐terminal domain contains a myristoylation motif, which was previously identified in several T3Es of P. syringae, indicating that effectors with this N‐terminal domain are targeted to host cellular membranes (White et al., 2009).

Enzymatic function

The C-terminal region of XopAI has similarity to predicted ADP-ribosyl transferase domains of the effector HopO1-1 of Pseudomonas syringae (Moreira et al., 2010).

XopAI was predicted to be a member of the arginine-specific mono-ADP-ribosyltransferase (mART) family. However, the crystal structure of XopAI revealed an altered active site that is unsuitable to bind the cofactor NAD+, but with the capability to capture an arginine-containing peptide from XopAI itself. Based on this finding, it was proposed that XopAI may not be a qualified mART, and it would exert different effects on host cells (Liu et al., 2019).

Structural homologs of XopAI are, among others, the HopU1 (Pseudomonas syringae T3SS-secreted effector HopU1, PDB code 3U0J), Tre1 (Serratia proteamaculans T6SS-secreted ADP-ribosyltransferase effector 1, PDB code 6DRH), ART2.2 (rat mART2.2, PDB code 1GXY), and ExoS (Pseudomonas aeruginosa exoenzyme S, PDB code 6GN8) (Liu et al., 2019).

Interaction partners

Conservation

In xanthomonads

XopAI is conserved in the Citrus canker strains, including X. citri pv. citri and X. citri pv. aurantifolii (ex X. fuscans pv. aurantifolii) (Moreira et al., 2010). However, XopAI is absent from the Citrus bacterial spot pathogen, X. euvesicatoria pv. citrumelonis (ex X. axonopodis pv. citrumelo) strain F1 (Jalan et al., 2011).

XopAI homologs were also found in X. citri pv. bilvae and X. citri pv. glycines, as well as in the species X. arboricola, X. hortorum, X. vesicatoria (Moreira et al., 2010; Liu et al., 2019).

In other plant pathogens/symbionts

Yes (e.g., Acidovorax citrulli, Pseudomonas syringae, Ralstonia solanacearum) (Moreira et al., 2010)

References

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 Santos M, 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

de Laia ML, Moreira LM, Gonçalves JF, Ferro MI, Pinto Rodrigues AC, dos Santos JN, Felestrino ÉB, Ferro JA (2019). Gene expression analysis identifies hypothetical genes that may be critical during the infection process of Xanthomonas citri subsp. citri.
Electron. J. Biotechnol. 42: 30-41. DOI: 10.1016/j.ejbt.2019.10.003

Fu Z (2008). Pseudomonas syringae type III secretion system and effectors. PhD thesis, University of Nebraska, Lincoln, USA.

Gaurav I, Thakur A, Kumar G, Long Q, Zhang K, Sidu RK, Thakur S, Sarkar RK, Kumar A, Iyaswamy A, Yang Z (2023). Delivery of apoplastic extracellular vesicles encapsulating green-synthesized silver nanoparticles to treat citrus canker. Nanomaterials (Basel) 13: 1306. DOI: 10.3390/nano13081306

Jalan N, Aritua V, Kumar D, Yu F, Jones JB, Graham JH, Setubal JC, Wang N (2011). Comparative genomic analysis of Xanthomonas axonopodis pv. citrumelo F1, which causes citrus bacterial spot disease, and related strains provides insights into virulence and host specificity. J. Bacteriol. 193: 6342-6357. DOI: 10.1128/JB.05777-11

Liu JH, Yang JY, Hsu DW, Lai YH, Li YP, Tsai YR, Hou MH (2019). Crystal structure-based exploration of arginine-containing peptide binding in the ADP-ribosyltransferase domain of the type III effector XopAI protein. Int. J. Mol. Sci. 20: 5085. DOI: 10.3390/ijms20205085

Moreira LM, Almeida NF Jr, Potnis N, Digiampietri LA, Adi SS, Bortolossi JC, da Silva AC, da Silva AM, de Moraes FE, de Oliveira JC, de Souza RF, Facincani AP, Ferraz AL, Ferro MI, Furlan LR, Gimenez DF, Jones JB, Kitajima EW, Laia ML, Leite RP Jr, Nishiyama MY, Rodrigues Neto J, Nociti LA, Norman DJ, Ostroski EH, Pereira HA Jr, Staskawicz BJ, Tezza RI, Ferro JA, Vinatzer BA, Setubal JC (2010). Novel insights into the genomic basis of citrus canker based on the genome sequences of two strains of Xanthomonas fuscans subsp. aurantifolii. BMC Genomics 11: 238. DOI: 10.1186/1471-2164-11-238

Noël L, Thieme F, Gäbler J, Büttner D, Bonas U (2003). XopC and XopJ, two novel type III effector proteins from Xanthomonas campestris pv. vesicatoria. J. Bacteriol. 185: 7092-7102. DOI: 10.1128/JB.185.24.7092-7102.2003

Stavrinides J, Ma W, Guttman DS (2006). Terminal reassortment drives the quantum evolution of type III effectors in bacterial pathogens. PLoS Pathog. 2: e104. DOI: 10.1371/journal.ppat.0020104

White FF, Potnis N, Jones JB, Koebnik R (2009). The type III effectors of Xanthomonas. Mol. Plant Pathol. 10: 749-766. DOI: 10.1111/j.1364-3703.2009.00590.x

bacteria/t3e/xopai.txt · Last modified: 2024/08/06 15:29 by rkoebnik