scholarly journals Toll/interleukin-1 Receptor Domain-Only Protein of Arabidopsis Thaliana AtTX14 2IR, Produced By Alternative Splicing, Can Induce Defense Responses

2021 ◽  
Author(s):  
Jaebeom Lim ◽  
Jinouk Yeon ◽  
Sang-Kee Song ◽  
Hankuil Yi
Keyword(s):  
Arabidopsis Thaliana ◽  
Pseudomonas Syringae ◽  
Positive Feedback ◽  
Transgenic Arabidopsis ◽  
Interleukin 1 ◽  
Defense Responses ◽  
Defense Signaling ◽  
Tir Domain ◽  
Constitutive Defense ◽  
Tir Domains

Abstract Toll/interleukin -1 receptor (TIR) domains, which have NAD+ cleavage activity, are used as signaling modules in NOD-like receptors for defense responses. It has been shown that TIR domains not only form homo- or heterodimers with TIR domain-containing proteins but also interact with various proteins. A previous study showed that overexpression of Arabidopsis thaliana (Arabidopsis) AtTX14, encoding an N-terminal TIR domain and a C-terminal domain with unknown function, resulted in dwarfism and constitutive defense signaling or autoimmunity. Transgenic Arabidopsis overexpressing AtTX14 displays enhanced defense responses and associated dwarf phenotypes at 28 °C compared with those at 22 °C, which differs from other mutant or transgenic Arabidopsis with constitutive defense responses. We found that AtTX14 is alternatively spliced to encode three different proteins, and the TIR domain itself can induce autoimmunity and elevated defense responses to the bacterial pathogen Pseudomonas syringae pv. tomato. In addition, we revealed that the transcription of AtTX14 is regulated by a positive feedback mechanism. With transient overexpression of three AtTX14 protein forms in tobacco leaves, providing a heterologous system free from the positive feedback of AtTX14 in Arabidopsis, we demonstrated that expression of a splicing variant encoding the TIR domain-only protein is sufficient to activate defense signaling. A deeper understanding of interaction networks involving AtTX14 will broaden our knowledge on how plant defense signaling is regulated in response to pathogen infection and ambient temperature changes.

Overexpression of a moso bamboo (Phyllostachys edulis) transcription factor gene PheWRKY1 enhances disease resistance in transgenic Arabidopsis thaliana

Botany ◽  
2013 ◽  
Vol 91 (7) ◽  
pp. 486-494 ◽  
Author(s):  
Xiao-Wei Cui ◽  
Ying Zhang ◽  
Fei-Yan Qi ◽  
Jian Gao ◽  
Yuan-Wen Chen ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Transcription Factor ◽  
Disease Resistance ◽  
Pseudomonas Syringae ◽  
Transgenic Arabidopsis ◽  
Defense Responses ◽  
Moso Bamboo ◽  
Photosynthetic Parameters ◽  
Phyllostachys Edulis ◽  
Pr Genes

Members of plant WRKY transcription factor families are implicated in defense responses and various other physiological processes. To study the function of WRKY transcription factors in moso bamboo (Phyllostachys edulis (Carrière) J. Houz.), a PheWRKY1 gene (GenBank accession number: GU944762) was cloned by reverse transcription polymerase chain reaction. An overexpression vector for this gene was constructed and transformed into Arabidopsis thaliana (L.) Heynh. by an agrobacterium-mediated method. To determine the effect of PheWRKY1 gene overexpression on disease resistance in A. thaliana, the photosynthetic parameters and the expression of pathogenesis-related (PR) genes were examined after Pseudomonas syringae PV Tomato DC3000 (Pst DC3000) infection. Compared to wild-type plants, most PheWRKY1-overexpressing plants did not exhibit spreading maceration to systemic leaves and had a better photosynthetic capacity after Pst DC3000 infection. Furthermore, PheWRKY1-overexpressing plants accumulated significantly more PR1, PR2, PR5, and nonexpressor of PR genes (NPR1) transcripts. These results demonstrated that transgenic Arabidopsis overexpressing PheWRKY1 gene exhibited improved resistance to bacterial infection.

scholarly journals Bacillus cereus AR156 Activates Defense Responses to Pseudomonas syringae pv. tomato in Arabidopsis thaliana Similarly to flg22

2018 ◽  
Vol 31 (3) ◽  
pp. 311-322 ◽  
Author(s):  
Shune Wang ◽  
Ying Zheng ◽  
Chun Gu ◽  
Chan He ◽  
Mengying Yang ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Bacillus Cereus ◽  
Pseudomonas Syringae ◽  
Transcriptional Profiling ◽  
Quantitative Polymerase Chain Reaction ◽  
Polymerase Chain Reaction Analysis ◽  
Defense Responses ◽  
Systemic Resistance ◽  
Callose Deposition ◽  
Plant Growth Promoting

Bacillus cereus AR156 (AR156) is a plant growth–promoting rhizobacterium capable of inducing systemic resistance to Pseudomonas syringae pv. tomato in Arabidopsis thaliana. Here, we show that, when applied to Arabidopsis leaves, AR156 acted similarly to flg22, a typical pathogen-associated molecular pattern (PAMP), in initiating PAMP-triggered immunity (PTI). AR156-elicited PTI responses included phosphorylation of MPK3 and MPK6, induction of the expression of defense-related genes PR1, FRK1, WRKY22, and WRKY29, production of reactive oxygen species, and callose deposition. Pretreatment with AR156 still significantly reduced P. syringae pv. tomato multiplication and disease severity in NahG transgenic plants and mutants sid2-2, jar1, etr1, ein2, npr1, and fls2. This suggests that AR156-induced PTI responses require neither salicylic acid, jasmonic acid, and ethylene signaling nor flagella receptor kinase FLS2, the receptor of flg22. On the other hand, AR156 and flg22 acted in concert to differentially regulate a number of AGO1-bound microRNAs that function to mediate PTI. A full-genome transcriptional profiling analysis indicated that AR156 and flg22 activated similar transcriptional programs, coregulating the expression of 117 genes; their concerted regulation of 16 genes was confirmed by real-time quantitative polymerase chain reaction analysis. These results suggest that AR156 activates basal defense responses to P. syringae pv. tomato in Arabidopsis, similarly to flg22.

scholarly journals Peptide-mediated Interference of TIR Domain Dimerization in MyD88 Inhibits Interleukin-1-dependent Activation of NF-κB

2005 ◽  
Vol 280 (16) ◽  
pp. 15809-15814 ◽  
Author(s):  
Maria Loiarro ◽  
Claudio Sette ◽  
Grazia Gallo ◽  
Andrea Ciacci ◽  
Nicola Fantò ◽  
...  
Keyword(s):  
Interleukin 1 ◽  
Cell System ◽  
Tir Domain ◽  
Loop Region ◽  
Good Target ◽  
A Cell ◽  
Tir Domains ◽  
Myeloid Differentiation Factor

Myeloid differentiation factor 88 (MyD88) plays a crucial role in the signaling pathways triggered by interleukin (IL)-1 and Toll-like receptors in several steps of innate host defense. A crucial event in this signaling pathway is represented by dimerization of MyD88, which allows the recruitment of downstream kinases like IRAK-1 and IRAK-4. Herein, we have investigated the function of the Toll/IL-1 receptor (TIR) domain in MyD88 homodimerization in cell-free andin vitroexperimental settings by using epta-peptides that mimic the BB-loop region of the conserved TIR domain of different proteins. By using a pull-down assay with purified glutathioneS-transferase-MyD88 TIR or co-immunoprecipitation experiments, we found that epta-peptides derived from the TIR domain of MyD88 and IL-18R are the most effective in inhibiting homodimerization with either the isolated TIR or full-length MyD88. Moreover, we demonstrated that a cell permeable analog of MyD88 epta-peptide inhibits homodimerization of MyD88 TIR domains in anin vitrocell system and significantly reduces IL-1 signaling, as assayed by activation of the downstream transcription factor NF-κB. Our results indicate that the BB-loop in TIR domain of MyD88 is a good target for specific inhibition of MyD88-mediated signalingin vivo.

scholarly journals Structure of the activated ROQ1 resistosome directly recognizing the pathogen effector XopQ

Science ◽  
2020 ◽  
Vol 370 (6521) ◽  
pp. eabd9993 ◽  
Author(s):  
Raoul Martin ◽  
Tiancong Qi ◽  
Haibo Zhang ◽  
Furong Liu ◽  
Miles King ◽  
...  
Keyword(s):  
Active Site ◽  
Nicotiana Benthamiana ◽  
Interleukin 1 ◽  
Leucine Rich Repeat ◽  
Tir Domain ◽  
Pathogen Effectors ◽  
Cryo Electron Microscopy ◽  
Pathogen Effector ◽  
Tir Domains ◽  
Direct Recognition

Plants and animals detect pathogen infection using intracellular nucleotide-binding leucine-rich repeat receptors (NLRs) that directly or indirectly recognize pathogen effectors and activate an immune response. How effector sensing triggers NLR activation remains poorly understood. Here we describe the 3.8-angstrom-resolution cryo–electron microscopy structure of the activated ROQ1 (recognition of XopQ 1), an NLR native to Nicotiana benthamiana with a Toll-like interleukin-1 receptor (TIR) domain bound to the Xanthomonaseuvesicatoria effector XopQ (Xanthomonas outer protein Q). ROQ1 directly binds to both the predicted active site and surface residues of XopQ while forming a tetrameric resistosome that brings together the TIR domains for downstream immune signaling. Our results suggest a mechanism for the direct recognition of effectors by NLRs leading to the oligomerization-dependent activation of a plant resistosome and signaling by the TIR domain.

scholarly journals Analysis of Resistance Gene-Mediated Defense Responses in Arabidopsis thaliana Plants Carrying a Mutation in CPR5

1998 ◽  
Vol 11 (12) ◽  
pp. 1196-1206 ◽  
Author(s):  
Jens Boch ◽  
Michelle L. Verbsky ◽  
Tara L. Robertson ◽  
John C. Larkin ◽  
Barbara N. Kunkel
Keyword(s):  
Gene Expression ◽  
Arabidopsis Thaliana ◽  
Resistance Gene ◽  
Pseudomonas Syringae ◽  
Bacterial Pathogen ◽  
Defense Responses ◽  
Negative Regulator ◽  
Suppressor Mutations ◽  
Defense Related Gene ◽  
Rapid Activation

In resistant plants, pathogen attack often leads to rapid activation of defense responses that limit multiplication and spread of the pathogen. To investigate the signaling mechanisms underlying this process, we carried out a screen for mutants in the signaling pathway governing resistance in Arabidopsis thaliana to the bacterial pathogen Pseudomonas syringae. This involved screening for suppressor mutations that restored resistance to a susceptible line carrying a mutation in the RPS2 resistance gene. A mutant that conferred resistance by activating defense responses in the absence of pathogens was isolated. This mutant, which carries a mutation at the CPR5 locus and was thus designated cpr5-2, exhibited resistance to P. syringae, spontaneous development of necrotic lesions, elevated PR gene expression in the absence of pathogens, and abnormal trichomes. Resistance gene-mediated defenses, including the hypersensitive response, restriction of pathogen growth, and induction of defense-related gene expression, were functional in cpr5-2 mutant plants. Additionally, in cpr5-2 plants RPS2-mediated induction of PR-1 expression was enhanced, whereas RPM1-mediated induction of ELI3 was not. These findings suggest that CPR5 encodes a negative regulator of the RPS2 signal transduc-tion pathway.

scholarly journals Vaccinia virus protein A46R targets multiple Toll-like–interleukin-1 receptor adaptors and contributes to virulence

2005 ◽  
Vol 201 (6) ◽  
pp. 1007-1018 ◽  
Author(s):  
Julianne Stack ◽  
Ismar R. Haga ◽  
Martina Schröder ◽  
Nathan W. Bartlett ◽  
Geraldine Maloney ◽  
...  
Keyword(s):  
Vaccinia Virus ◽  
Interleukin 1 ◽  
Nuclear Factor Κb ◽  
Virus Protein ◽  
Innate Defense ◽  
Tir Domain ◽  
Mitogen Activated Protein ◽  
Key Aspects ◽  
Tir Domains ◽  
Myeloid Differentiation Factor

Viral immune evasion strategies target key aspects of the host antiviral response. Recently, it has been recognized that Toll-like receptors (TLRs) have a role in innate defense against viruses. Here, we define the function of the vaccinia virus (VV) protein A46R and show it inhibits intracellular signalling by a range of TLRs. TLR signalling is triggered by homotypic interactions between the Toll-like–interleukin-1 resistance (TIR) domains of the receptors and adaptor molecules. A46R contains a TIR domain and is the only viral TIR domain–containing protein identified to date. We demonstrate that A46R targets the host TIR adaptors myeloid differentiation factor 88 (MyD88), MyD88 adaptor-like, TIR domain–containing adaptor inducing IFN-β (TRIF), and the TRIF-related adaptor molecule and thereby interferes with downstream activation of mitogen-activated protein kinases and nuclear factor κB. TRIF mediates activation of interferon (IFN) regulatory factor 3 (IRF3) and induction of IFN-β by TLR3 and TLR4 and suppresses VV replication in macrophages. Here, A46R disrupted TRIF-induced IRF3 activation and induction of the TRIF-dependent gene regulated on activation, normal T cell expressed and secreted. Furthermore, we show that A46R is functionally distinct from another described VV TLR inhibitor, A52R. Importantly, VV lacking the A46R gene was attenuated in a murine intranasal model, demonstrating the importance of A46R for VV virulence.

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