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- | ====== AvrBs3 ====== | ||
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- | Author: [[https:// | ||
- | Internal reviewer: Jens Boch\\ | ||
- | Expert reviewer: FIXME | ||
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- | Class: AvrBs3\\ | ||
- | Family: Transcription Activator-Like (TAL) Effectors, TALEs (previously: | ||
- | Prototype: AvrBs3 (// | ||
- | RefSeq ID: [[https:// | ||
- | 3D structure: [[https:// | ||
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- | ===== Biological function ===== | ||
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- | === How discovered? === | ||
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- | The gene //avrBs3 //was cloned in 1989 and was the first gene described of the TAL effector (TALE) family (Minsavage //et al//., 1990). Different resistant and susceptible cultivars of peppers were inoculated with //Xcv// strains 71-21 and 82-8 (Bonas //et al//., 1989). The pepper cultivar ECW-30R carries the resistance gene //Bs3 //and inoculation of these //Xcv// strains provoked a hypersensitive response (HR) (Bonas //et al//., 1989). This indicated that both //Xcv// strains contained //avrBs3//. | ||
- | === (Experimental) evidence for being a T3E === | ||
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- | AvrBs3 is secreted and translocated into the plant via the Hrp type III secretion system (Bonas //et al//., 1991; Van den Ackerveken //et al//., 1996; Bonas //et al//., 1999). In contrast to wild-type bacteria, an //Xcv// mutant carrying a deletion in the conserved //hrp// gene //hrcV// did not secrete AvrBs3 indicating that AvrBs3 is transported by the Hrp system (Rossier //et al//., 1999). In its C-terminal domain, AvrBs3 carries an acidic activation domain which is functional in plant cells (Van den Ackerveken //et al//., 1996). Two nuclear localization signals in the C-terminal domain of AvrBs3 facilitate transport into the plant cell nucleus (Van den Ackerveken //et al//., 1996; Szurek //et al//., 2002). These eukaryotic features support the role of AvrBs3 and members of the TALE family within the eukaryotic host cell. | ||
- | === Regulation === | ||
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- | Unlike most other type III effectors, expression of //avrBs3// is not dependend on the hrp regulon and the gene does not contain a PIP box in its promoter region. It is expressed constitutively in cells grown in minimal or complex medium and in planta (Knoop //et al//., 1991). | ||
- | === Phenotypes === | ||
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- | AvrBs3, as well as other members of the TALE-family, | ||
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- | Expression analysis using gene promoter fusion and western blot analysis demonstrated that //avrBs3// was expressed and resulted in a 122 kDa protein (1164 aa) which was detectable using a specific polyclonal antibody (Bonas //et al//., 1989). The AvrBs3 effector protein elicits two different types of responses in resistant or susceptible plants. Differential cDNA analysis from susceptible pepper plants infected with //Xcv// with or without AvrBs3 led to the discovery of //upa// (upregulated by AvrBs3) genes whose expression is induced by AvrBs3. These //upa// genes all share a conserved promoter element, known as the //UPA// box (Kay //et al.//, 2007). //upa20// act as a master regulator of cell enlargement causing the hypertrophy symptoms associated with AvrBs3. Silencing of //upa20// decreased cell hypertrophy in infected plants while the expression of //upa20// led to hypertrophy in uninfected plants (Kay //et al//., 2007). In resistant pepper plants, the promoter of //Bs3// contains a //UPA// box that is bound by AvrBs3 resulting in the transcription of the gene //Bs3//. //Bs3// encodes a protein that is homologous to flavine-dependent mono-oxygenases and its expression causes rapid cell death. | ||
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- | The central region of the //avrBs3// gene consists of 17.5 nearly identical 102 bp repeats. Each repeat encodes 34 amino acids (Bonas //et al//., 1989). Repeat variable di-residues (RVDs) at positions 12 and 13 determine the specificity of each repeat (Boch //et al//., 2009; Moscou & Bogdanove, 2009). AvrBs3 binds its UPA box with the C-terminal activation domain directed towards the coding sequence of target genes. | ||
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- | Gene //Bs3// was introduced into the ECW background to generate near-isogenic line resistant ECW-30R (Bonas //et al//., 1989; Bonas //et al//., 1991). ECW-30R was inoculated using different //Xcv// strains. //Xcv// lines 71-21 and 82-8 induces a hypersensitive response HR in ECW-30R, leading to programmed cell death and thus preventing the spread of the pathogen (Bonas //et al//., 1989; Bonas //et al//., 1991). Different //Xcv// strains were inoculated on susceptible (Early Cal Wonder; ECW) pepper plants. Hypertrophy (i.e. enlargement of mesophyll cells) was observed (Bonas //et al//., 1989; Bonas //et al//., 1991; Kay //et al//., 2007; Marois //et al//., 2002). It was also speculated that this hypertrophy facilitated bacterial colonization (Kay //et al//., 2007). // | ||
- | === Localization === | ||
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- | The //avrBs3// gene is localized on pXV11, a self-transmissible plasmid, and was initially isolated from //Xcv// strain 71-21 (Bonas //et al//., 1989). Using complementation of //Xcv// strain 85-10 (virulent on pepper ECW-30R), a 5-kb fragment including //avrBs3// was discovered (Bonas //et al//., 1989). | ||
- | === Enzymatic function === | ||
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- | DNA-binding protein. Transcriptional activator. | ||
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- | === Interaction partners === | ||
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- | Importin alpha (Szurek //et al.//, 2001) interacts with the nuclear localization sequences of AvrBs3. The basal transcription factor IIA, gamma subunit from rice interacts with a region in the C-terminal domain of TALEs (Yuan //et al//., 2016) and similar interactions might be possible for AvrBs3, too. AvrBs3 and the TALE-family of effectors bind to DNA (Kay //et al//., 2007; Römer //et al//., 2007) with their N-terminal domain exhibiting general DNA-binding properties (Gao //et al.//, 2012) and the repeat region facilitating specific interaction to DNA bases (Boch //et al//., 2009; Moscou and Bogdanove, 2009). | ||
- | ===== Conservation ===== | ||
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- | === In xanthomonads === | ||
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- | Yes in many pathovars, but not necesssarily all strains within a pathovar. | ||
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- | === In other plant pathogens/ | ||
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- | Yes: Genes homologous to //avrBs3// of // | ||
- | ===== References ===== | ||
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- | Boch J, Scholze H, Schornack S, Landgraf A, Hahn S, Kay S, Lahaye T, Nickstadt A, Bonas U (2009). Breaking the code of DNA binding specificity of TAL-type III effectors. Science 326: 1509-1512. DOI: [[http:// | ||
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- | Bonas U, Stall, RE, Staskawicz B (1989). Genetic and structural characterization of the avirulence gene //avrBs3// from // | ||
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- | Bonas U, Schulte R, Fenselau S, Minsavage GV, Staskawicz BJ, Stall RE (1991). Isolation of a gene cluster from // | ||
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- | Bonas U, Van den Ackerveken G (1999). Gene-for-gene interactions: | ||
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- | de Lange O, Schreiber T, Schandry N, Radeck J, Braun KH, Koszinowski J, Heuer H, Strauß A, Lahaye T (2013). Breaking the DNA-binding code of //Ralstonia solanacearum// | ||
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- | de Lange O, Wolf C, Dietze J, Elsaesser J, Morbitzer R, Lahaye T (2014). Programmable DNA-binding proteins from Burkholderia provide a fresh perspective on the TALE-like repeat domain. Nuc. Acids Res. 42: 7436-7449. DOI: [[https:// | ||
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- | de Lange O, Wolf C, Thiel P, Krüger J, Kleusch C, Kohlbacher O, Lahaye T (2015). DNA-binding proteins from marine bacteria expand the known sequence diversity of TALE-like repeats. Nuc. Acids Res. 43: 10065-10080. DOI: [[https:// | ||
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- | Deng D, Yan C, Pan X, Mahfouz M, Wang J, Zhu JK, Shi Y, Yan N (2012a). Structural basis for sequence-specific recognition of DNA by TAL effectors. Science 335: 720-723. DOI: [[https:// | ||
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- | Deng D, Yan C, Wu J, Pan X, Yan N (2014). Revisiting the TALE repeat. Protein Cell 5: 297-306. DOI: [[https:// | ||
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- | Deng D, Yin P, Yan C, Pan X, Gong X, Qi S, Xie T, Mahfouz M, Zhu JK, Yan N, Shi Y (2012b). Recognition of methylated DNA by TAL effectors. Cell Res. 22: 1502-1504. DOI: [[https:// | ||
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- | Gao H, Wu X, Chai J, Han Z (2012). Crystal structure of a TALE protein reveals an extended N-terminal DNA binding region. Cell Res. 22: 1716-1720. DOI: [[https:// | ||
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- | Herbers K, Conrads-Strauch J, Bonas U (1992). Race-specificity of plant resistance to bacterial spot disease determined by repetitive motifs in a bacterial avirulence protein. Nature 356: 172-174. DOI: [[https:// | ||
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- | Heuer H, Yin YN, Xue QY, Smalla K, Guo JH (2007). Repeat domain diversity of avrBs3-like genes in // | ||
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- | Hopkins CM, White FF, Choi SH, Guo A, Leach JE (1992). Identification of a family of avirulence genes from // | ||
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- | Ji ZY, Xiong L, Zou LF, Li YR, Ma WX, Liu L, Zakria M, Ji GH, Chen GY (2014). AvrXa7-Xa7 mediated defense in rice can be suppressed by transcriptional activator-like effectors TAL6 and TAL11a from // | ||
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- | Kay S, Hahn S, Marois E, Hause G, Bonas U (2007). A bacterial effector acts as a plant transcription factor and induces a cell size regulator. Science 318: 648-651. DOI: [[http:// | ||
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- | Knoop V, Staskawicz B, Bonas U (1991). Expression of the avirulence gene //avrBs3// from // | ||
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- | Lackner G, Moebius N, Partida-Martinez LP, Boland S, Hertweck C (2011). Evolution of an endofungal lifestyle: Deductions from the // | ||
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- | Mak AN, Bradley P, Cernadas RA, Bogdanove AJ, Stoddard BL (2012). The crystal structure of TAL effector PthXo1 bound to its DNA target. Science 335: 716-719. DOI: [[https:// | ||
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- | Marois E, Van den Ackerveken G, Bonas U (2002). The // | ||
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- | Minsavage GV, Dahlbeck D, Whalen MC, Kearney B, Bonas U, Staskawicz BJ, Stall, RE (1990). Gene-for-gene relationships specifying disease resistance in // | ||
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- | Moscou MJ, Bogdanove AJ (2009). A simple cipher governs DNA recognition by TAL effectors. Science 326: 1501. DOI: [[http:// | ||
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- | Murakami MT, Sforça ML, Neves JL, Paiva JH, Domingues MN, Pereira AL, Zeri AC, Benedetti CE (2010). The repeat domain of the type III effector protein PthA shows a TPR-like structure and undergoes conformational changes upon DNA interaction. Proteins 78: 3386-3395. DOI: [[https:// | ||
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- | Römer P, Hahn S, Jordan T, Strauss T, Bonas U, Lahaye T (2007). Plant pathogen recognition mediated by promoter activation of the pepper Bs3 resistance gene. Science 318: 645-648. DOI: [[https:// | ||
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- | Rossier O, Wengelnik K, Hahn K, Bonas U (1999). The // | ||
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- | Scheibner F, Marillonnet S, Büttner D (2017). The TAL effector AvrBs3 from // | ||
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- | Stella S, Molina R, Yefimenko I, Prieto J, Silva G, Bertonati C, Juillerat A, Duchateau P, Montoya G (2013). Structure of the AvrBs3–DNA complex provides new insights into the initial thymine-recognition mechanism. Acta Cryst. 69: 1707-1716. DOI: [[http:// | ||
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- | Szurek B, Marois E, Bonas U, Van den Ackerveken G (2001). Eukaryotic features of the // | ||
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- | Szurek B, Rossier O, Hause G, Bonas U (2002). Type III-dependent translocation of the // | ||
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- | Van den Ackerveken G, Marois E, Bonas U (1996). Recognition of the bacterial avirulence protein AvrBs3 occurs inside the host plant cell. Cell 87: 1307-1316. DOI: [[https:// | ||
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- | Yin P, Deng D, Yan C, Pan X, Xi JJ, Yan N, Shi Y (2012). Specific DNA-RNA hybrid recognition by TAL effectors. Cell Rep. 2: 707-713. DOI: 1[[https:// | ||
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- | ===== Further reading ===== | ||
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- | Boch J, Bonas U (2010). // | ||
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- | Boch J, Bonas U, Lahaye T (2014). TAL effectors - pathogen strategies and plant resistance engineering. New Phytol. 204: 823-832. DOI: [[https:// | ||
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- | Bogdanove AJ, Schornack S, Lahaye T (2010). TAL effectors: finding plant genes for disease and defense. Curr. Opin. Plant Biol. 13: 394-401. DOI: [[https:// | ||
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- | Doyle EL, Stoddard BL, Voytas DF, Bogdanove AJ (2013). TAL effectors: highly adaptable phytobacterial virulence factors and readily engineered DNA-targeting proteins. Trends Cell Biol. 23: 390-398. DOI: [[https:// | ||
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- | Hutin M, Pérez-Quintero AL, Lopez C, Szurek B (2015). MorTAL Kombat: the story of defense against TAL effectors through loss-of-susceptibility. Front. Plant Sci. 6: 535. DOI: [[https:// | ||
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- | Scholze H, Boch J (2010). TAL effector-DNA specificity. Virulence 1: 428-432. DOI: [[https:// | ||
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- | Scholze H, Boch J (2011). TAL effectors are remote controls for gene activation. Curr. Opin. Microbiol. 14: 47-53. DOI: [[https:// | ||
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- | Yuan M, Ke Y, Huang R, Ma L, Yang Z, Chu Z, Xiao J, Li X, Wang S (2016). A host basal transcription factor is a key component for infection of rice by TALE-carrying bacteria. Elife 5: DOI: [[https:// | ||
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- | Zhang J, Yin Z, White F (2015). TAL effectors and the executor //R// genes. Front. Plant Sci. 6: 641. DOI: [[https:// | ||