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bacteria:t3e:avrbs2

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bacteria:t3e:avrbs2 [2020/07/13 14:36]
rkoebnik [AvrBs2]
bacteria:t3e:avrbs2 [2020/07/17 10:32] (current)
rkoebnik [Biological function]
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 Indirectly – the pathovars that induced //Bs2//-mediated hypersensitivity were classified as having AvrBs2 activity (Kearney & Staskawicz, 1990). Indirectly – the pathovars that induced //Bs2//-mediated hypersensitivity were classified as having AvrBs2 activity (Kearney & Staskawicz, 1990).
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 === (Experimental) evidence for being a T3E === === (Experimental) evidence for being a T3E ===
  
-AvrBs2 fused to the calmodulin-activated adenylate cyclase domain was shown to translocate into plant cells (cytosol), detected through rise of cAMP levels inside the plant tissue. The //hrpF//  <sup>-</sup>   mutant was used as a negative control to prove the translocation process. Further it was shown that AvrBs2 contains two N-terminal secretion and translocation signals: first for secretion and the second for enhancing translocation (Casper-Lindley //et al//., 2002). +AvrBs2 fused to the calmodulin-activated adenylate cyclase domain was shown to translocate into plant cells (cytosol), detected through rise of cAMP levels inside the plant tissue. The //hrpF// <sup>-</sup>  mutant was used as a negative control to prove the translocation process. Further it was shown that AvrBs2 contains two N-terminal secretion and translocation signals: first for secretion and the second for enhancing translocation (Casper-Lindley //et al//., 2002).
 === Regulation === === Regulation ===
  
-qRT-PCR revealed that transcript levels of 15 out of 18 tested non-TAL effector genes (as well as the regulatory genes //hrpG//  and //hrpX//), including //avrBs2//, were significantly reduced in the //Xanthomonas oryzae//  pv. //oryzae//  Δ//xrvC//  mutant compared with those in the wild-type strain PXO99<sup>A</sup>   (Liu //et al//., 2016). +qRT-PCR revealed that transcript levels of 15 out of 18 tested non-TAL effector genes (as well as the regulatory genes //hrpG// and //hrpX//), including //avrBs2//, were significantly reduced in the //Xanthomonas oryzae// pv. //oryzae// Δ//xrvC// mutant compared with those in the wild-type strain PXO99<sup>A</sup>  (Liu //et al//., 2016).
- +
-Transcriptome analysis (RNA-seq) and qRT-PCR have shown that //avrBs2//  gene expression is downregulated in a //X. citri//  pv. //citri//  Δ//phoP//  mutant, indicating that PhoP is a positive regulator of //avrBs2//  expression (Wei //et al//., 2019).+
  
 +Transcriptome analysis (RNA-seq) and qRT-PCR have shown that //avrBs2// gene expression is downregulated in a //X. citri// pv. //citri// Δ//phoP// mutant, indicating that PhoP is a positive regulator of //avrBs2// expression (Wei //et al//., 2019).
 === Phenotypes === === Phenotypes ===
  
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   * Induced expression of AvrBs2 in transgenic cell cultures was shown to dramatically suppress flg22-induced and chitin-induced immune responses, such as ROS burst and PR gene expression (Li //et al//., 2015).   * Induced expression of AvrBs2 in transgenic cell cultures was shown to dramatically suppress flg22-induced and chitin-induced immune responses, such as ROS burst and PR gene expression (Li //et al//., 2015).
   * A ∆//xopK//  mutant strain of //Xanthomonas phaseoli//  pv. //manihotis//  (aka //Xanthomonas axonopodis//  pv. //manihotis//) showed reduced growth in planta and delayed spread through the vasculature system of cassava. Moreover, the ∆avrBs2 mutant strain exhibited reduced water-soaking symptoms at the site of inoculation (Mutka //et al.//, 2016).   * A ∆//xopK//  mutant strain of //Xanthomonas phaseoli//  pv. //manihotis//  (aka //Xanthomonas axonopodis//  pv. //manihotis//) showed reduced growth in planta and delayed spread through the vasculature system of cassava. Moreover, the ∆avrBs2 mutant strain exhibited reduced water-soaking symptoms at the site of inoculation (Mutka //et al.//, 2016).
 +  * //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. A screen for //Xanthomonas//  effectors which can suppress XopQ-XopX induced rice immune responses, led to the identification of five effectors, namely XopU, XopV, XopP, XopG and AvrBs2, that could individually suppress these immune responses. These results suggest a complex interplay of //Xanthomonas//  T3SS effectors in suppression of both pathogen-triggered immunity and effector-triggered immunity to promote virulence on rice (Deb //et al.//, 2020).
 === Localization === === Localization ===
  
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 Coplin DL (1989). Plasmids and their role in the evolution of plant pathogenic bacteria. Ann. Rev. Phytopathol. 27: 187-212. DOI: [[https://doi.org/10.1146/annurev.py.27.090189.001155|10.1146/annurev.py.27.090189.001155]] Coplin DL (1989). Plasmids and their role in the evolution of plant pathogenic bacteria. Ann. Rev. Phytopathol. 27: 187-212. DOI: [[https://doi.org/10.1146/annurev.py.27.090189.001155|10.1146/annurev.py.27.090189.001155]]
 +
 +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., in press. DOI: [[https://doi.org/10.1111/tpj.14924|10.1111/tpj.14924]]
  
 Gassmann W, Dahlbeck D, Chesnokova O, Minsavage GV, Jones JB, Staskawicz BJ (2000). Molecular evolution of virulence in natural field strains of //Xanthomonas campestris// pv. //vesicatoria//. J. Bacteriol. 182: 7053-7059. DOI: [[https://doi.org/10.1128/jb.182.24.7053-7059.2000|10.1128/jb.182.24.7053-7059.2000]] Gassmann W, Dahlbeck D, Chesnokova O, Minsavage GV, Jones JB, Staskawicz BJ (2000). Molecular evolution of virulence in natural field strains of //Xanthomonas campestris// pv. //vesicatoria//. J. Bacteriol. 182: 7053-7059. DOI: [[https://doi.org/10.1128/jb.182.24.7053-7059.2000|10.1128/jb.182.24.7053-7059.2000]]
bacteria/t3e/avrbs2.1594643787.txt.gz · Last modified: 2020/07/13 14:36 by rkoebnik