scholarly journals Nuclear Localization of HopA1Pss61 Is Required for Effector-Triggered Immunity

Plants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 888
Author(s):  
Hobin Kang ◽  
Quang-Minh Nguyen ◽  
Arya Bagus Boedi Iswanto ◽  
Jong Chan Hong ◽  
Saikat Bhattacharjee ◽  
...  
Keyword(s):  
Cell Death ◽  
Pseudomonas Syringae ◽  
Nuclear Localization ◽  
Functional Characterization ◽  
Defense Responses ◽  
Disease Resistance Gene ◽  
In Planta ◽  
Resistance Proteins ◽  
Cell Death Response ◽  
Effector Triggered Immunity

Plant resistance proteins recognize cognate pathogen avirulence proteins (also named effectors) to implement the innate immune responses called effector-triggered immunity. Previously, we reported that hopA1 from Pseudomonas syringae pv. syringae strain 61 was identified as an avr gene for Arabidopsis thaliana. Using a forward genetic screen approach, we cloned a hopA1-specific TIR-NBS-LRR class disease resistance gene, RESISTANCE TO PSEUDOMONAS SYRINGAE6 (RPS6). Many resistance proteins indirectly recognize effectors, and RPS6 is thought to interact with HopA1Pss61 indirectly by surveillance of an effector target. However, the involved target protein is currently unknown. Here, we show RPS6 is the only R protein that recognizes HopA1Pss61 in Arabidopsis wild-type Col-0 accession. Both RPS6 and HopA1Pss61 are co-localized to the nucleus and cytoplasm. HopA1Pss61 is also distributed in plasma membrane and plasmodesmata. Interestingly, nuclear localization of HopA1Pss61 is required to induce cell death as NES-HopA1Pss61 suppresses the level of cell death in Nicotiana benthamiana. In addition, in planta expression of hopA1Pss61 led to defense responses, such as a dwarf morphology, a cell death response, inhibition of bacterial growth, and increased accumulation of defense marker proteins in transgenic Arabidopsis. Functional characterization of HopA1Pss61 and RPS6 will provide an important piece of the ETI puzzle.

scholarly journals A Salicylic Acid–Induced Lectin-Like Protein Plays a Positive Role in the Effector-Triggered Immunity Response of Arabidopsis thaliana to Pseudomonas syringae Avr-Rpm1

2013 ◽  
Vol 26 (12) ◽  
pp. 1395-1406 ◽  
Author(s):  
Grace Armijo ◽  
Paula Salinas ◽  
Mariela Inés Monteoliva ◽  
Aldo Seguel ◽  
Consuelo García ◽  
...  
Keyword(s):  
Cell Death ◽  
Salicylic Acid ◽  
Pseudomonas Syringae ◽  
Functional Characterization ◽  
Constitutive Expression ◽  
Hypersensitive Reaction ◽  
Positive Role ◽  
Legume Lectin ◽  
Immunity Response ◽  
Effector Triggered Immunity

Salicylic acid (SA) is one of the key hormones that orchestrate the pathogen-induced immune response in plants. This response is often characterized by the activation of a local hypersensitive reaction involving programmed cell death, which constrains proliferation of biotrophic pathogens. Here, we report the identification and functional characterization of an SA-induced legume lectin-like protein 1 (SAI-LLP1), which is coded by a gene that belongs to the group of early SA-activated Arabidopsis genes. SAI-LLP1 expression is induced upon inoculation with avirulent strains of Pseudomonas syringae pv. tomato via an SA-dependent mechanism. Constitutive expression of SAI-LLP1 restrains proliferation of P. syringae pv. tomato Avr-Rpm1 and triggers more cell death in inoculated leaves. Cellular and biochemical evidence indicates that SAI-LLP1 is a glycoprotein located primarily at the apoplastic side of the plasma membrane. This work indicates that SAI-LLP1 is involved in resistance to P. syringae pv. tomato Avr-Rpm1 in Arabidopsis, as a component of the SA-mediated defense processes associated with the effector-triggered immunity response.

scholarly journals Mutational Analysis of the Arabidopsis RPS2 Disease Resistance Gene and the Corresponding Pseudomonas syringae avrRpt2 Avirulence Gene

2001 ◽  
Vol 14 (2) ◽  
pp. 181-188 ◽  
Author(s):  
Michael J. Axtell ◽  
Timothy W. McNellis ◽  
Mary Beth Mudgett ◽  
Caroline S. Hsu ◽  
Brian J. Staskawicz
Keyword(s):  
Disease Resistance ◽  
Resistance Gene ◽  
Pseudomonas Syringae ◽  
Resistance Genes ◽  
Mutational Analysis ◽  
Defense Responses ◽  
Avirulence Gene ◽  
Disease Resistance Gene ◽  
In Planta ◽  
Hypersensitive Cell Death

Plants have evolved a large number of disease resistance genes that encode proteins containing conserved structural motifs that function to recognize pathogen signals and to initiate defense responses. The Arabidopsis RPS2 gene encodes a protein representative of the nucleotide-binding site-leucine-rich repeat (NBS-LRR) class of plant resistance proteins. RPS2 specifically recognizes Pseudomonas syringae pv. tomato strains expressing the avrRpt2 gene and initiates defense responses to bacteria carrying avrRpt2, including a hypersensitive cell death response (HR). We present an in planta mutagenesis experiment that resulted in the isolation of a series of rps2 and avrRpt2 alleles that disrupt the RPS2-avrRpt2 gene-for-gene interaction. Seven novel avrRpt2 alleles incapable of eliciting an RPS2-dependent HR all encode proteins with lesions in the C-terminal portion of AvrRpt2 previously shown to be sufficient for RPS2 recognition. Ten novel rps2 alleles were characterized with mutations in the NBS and the LRR. Several of these alleles code for point mutations in motifs that are conserved among NBS-LRR resistance genes, including the third LRR, which suggests the importance of these motifs for resistance gene function.

scholarly journals Engineering a Decoy Substrate in Soybean to Enable Recognition of the Soybean Mosaic Virus NIa Protease

2019 ◽  
Vol 32 (6) ◽  
pp. 760-769 ◽  
Author(s):  
Matthew Helm ◽  
Mingsheng Qi ◽  
Shayan Sarkar ◽  
Haiyue Yu ◽  
Steven A. Whitham ◽  
...  
Keyword(s):  
Cell Death ◽  
Mosaic Virus ◽  
Pseudomonas Syringae ◽  
Cleavage Site ◽  
Soybean Mosaic Virus ◽  
Defense Responses ◽  
Cell Death Response ◽  
Arabidopsis Protein ◽  
Systemic Spread ◽  
Nia Protease

In Arabidopsis, recognition of the AvrPphB effector protease from Pseudomonas syringae is mediated by the disease resistance (R) protein RPS5, which is activated by AvrPphB-induced cleavage of the Arabidopsis protein kinase PBS1. The recognition specificity of RPS5 can be altered by substituting the AvrPphB cleavage site within PBS1 with cleavage sequences for other proteases, including proteases from viruses. AvrPphB also activates defense responses in soybean (Glycine max), suggesting that soybean may contain an R protein analogous to RPS5. It was unknown, however, whether this response is mediated by cleavage of a soybean PBS1-like protein. Here, we show that soybean contains three PBS1 orthologs and that their products are cleaved by AvrPphB. Further, transient expression of soybean PBS1 derivatives containing a five-alanine insertion at their AvrPphB cleavage sites activated cell death in soybean protoplasts, demonstrating that soybean likely contains an AvrPphB-specific resistance protein that is activated by a conformational change in soybean PBS1 proteins. Significantly, we show that a soybean PBS1 decoy protein modified to contain a cleavage site for the soybean mosaic virus (SMV) NIa protease triggers cell death in soybean protoplasts when cleaved by this protease, indicating that the PBS1 decoy approach will work in soybean, using endogenous PBS1 genes. Lastly, we show that activation of the AvrPphB-dependent cell death response effectively inhibits systemic spread of SMV in soybean. These data also indicate that decoy engineering may be feasible in other crop plant species that recognize AvrPphB protease activity.

scholarly journals Engineering a decoy substrate in soybean to enable recognition of the Soybean Mosaic Virus NIa protease

2018 ◽  
Author(s):  
Matthew Helm ◽  
Mingsheng Qi ◽  
Shayan Sarkar ◽  
Haiyue Yu ◽  
Steven A. Whitham ◽  
...  
Keyword(s):  
Cell Death ◽  
Mosaic Virus ◽  
Pseudomonas Syringae ◽  
Cleavage Site ◽  
Soybean Mosaic Virus ◽  
Defense Responses ◽  
Cell Death Response ◽  
Arabidopsis Protein ◽  
Systemic Spread ◽  
Nia Protease

In Arabidopsis, recognition of the AvrPphB effector protease from Pseudomonas syringae is mediated by the disease resistance (R) protein RPS5, which is activated by AvrPphB-induced cleavage of the Arabidopsis protein kinase PBS1. The recognition specificity of RPS5 can be altered by substituting the AvrPphB cleavage site within PBS1 with cleavage sequences for other proteases, including proteases from viruses. AvrPphB also activates defense responses in soybean (Glycine max), suggesting that soybean may contain an R protein analogous to RPS5. It was unknown, however, whether this response is mediated by cleavage of a soybean PBS1-like protein. Here we show that soybean contains three PBS1 orthologs and that their products are cleaved by AvrPphB. Further, transient expression of soybean PBS1 derivatives containing a five-alanine insertion at their AvrPphB cleavage sites activated cell death in soybean protoplasts, demonstrating that soybean likely contains an AvrPphB-specific resistance protein that is activated by a conformational change in soybean PBS1 proteins. Significantly, we show that a soybean PBS1 decoy protein modified to contain a cleavage site for the Soybean mosaic virus (SMV) NIa protease triggers cell death in soybean protoplasts when cleaved by this protease, indicating that the PBS1 decoy approach will work in soybean using endogenous PBS1 genes. Lastly, we show that activation of the AvrPphB-dependent cell death response effectively inhibits systemic spread of SMV in soybean. These data also indicate that decoy engineering may be feasible in other crop plant species that recognize AvrPphB protease activity.

scholarly journals Optimizing the PBS1 Decoy System to Confer Resistance to Potyvirus Infection in Arabidopsis and Soybean

2020 ◽  
Vol 33 (7) ◽  
pp. 932-944 ◽  
Author(s):  
Sarah E. Pottinger ◽  
Aurelie Bak ◽  
Alexandra Margets ◽  
Matthew Helm ◽  
Lucas Tang ◽  
...  
Keyword(s):  
Cell Death ◽  
Plasma Membrane ◽  
Mosaic Virus ◽  
Pseudomonas Syringae ◽  
Soybean Mosaic Virus ◽  
Aphid Transmission ◽  
Defense Responses ◽  
Cell Death Response ◽  
Dependent Cell ◽  
Nia Protease

The Arabidopsis resistance protein RPS5 is activated by proteolytic cleavage of the protein kinase PBS1 by the Pseudomonas syringae effector protease AvrPphB. We have previously shown that replacing seven amino acids at the cleavage site of PBS1 with a motif cleaved by the NIa protease of turnip mosaic virus (TuMV) enables RPS5 activation upon TuMV infection. However, this engineered resistance conferred a trailing necrosis phenotype indicative of a cell-death response too slow to contain the virus. We theorized this could result from a positional mismatch within the cell between PBS1TuMV, RPS5, and the NIa protease. To test this, we relocalized PBS1TuMV and RPS5 to cellular sites of NIa accumulation. These experiments revealed that relocation of RPS5 away from the plasma membrane compromised RPS5-dependent cell death in Nicotiana benthamiana, even though PBS1 was efficiently cleaved. As an alternative approach, we tested whether overexpression of plasma membrane–localized PBS1TuMV could enhance RPS5 activation by TuMV. Significantly, overexpressing the PBS1TuMV decoy protein conferred complete resistance to TuMV when delivered by either agrobacterium or by aphid transmission, showing that RPS5-mediated defense responses are effective against bacterial and viral pathogens. Lastly, we have now extended this PBS1 decoy approach to soybean by modifying a soybean PBS1 ortholog to be cleaved by the NIa protease of soybean mosaic virus (SMV). Transgenic overexpression of this soybean PBS1 decoy conferred immunity to SMV, demonstrating that we can use endogenous PBS1 proteins in crop plants to engineer economically relevant disease resistant traits.

scholarly journals Optimizing the PBS1 Decoy System to Confer Resistance to Potyvirus Infection in Arabidopsis and Soybean

2020 ◽  
Author(s):  
Sarah E. Pottinger ◽  
Aurelie Bak ◽  
Alexandra Margets ◽  
Matthew Helm ◽  
Lucas Tang ◽  
...  
Keyword(s):  
Cell Death ◽  
Plasma Membrane ◽  
Mosaic Virus ◽  
Pseudomonas Syringae ◽  
Soybean Mosaic Virus ◽  
Aphid Transmission ◽  
Defense Responses ◽  
Cell Death Response ◽  
Dependent Cell ◽  
Nia Protease

ABSTRACTThe Arabidopsis resistance protein RPS5 is activated by proteolytic cleavage of the protein kinase PBS1 by the Pseudomonas syringae effector protease AvrPphB. We have previously shown that replacing seven amino acids at the cleavage site of PBS1 with a motif cleaved by the NIa protease of turnip mosaic virus (TuMV) enables RPS5 activation upon TuMV infection. However, this engineered resistance conferred a trailing necrosis phenotype indicative of a cell death response too slow to contain the virus. We theorized this could result from a positional mismatch within the cell between PBS1TuMV, RPS5 and the NIa protease. To test this, we re-localized PBS1TuMV and RPS5 to cellular sites of NIa accumulation. These experiments revealed that relocation of RPS5 away from the plasma membrane compromised RPS5-dependent cell death in N. benthamiana, even though PBS1 was efficiently cleaved. As an alternative approach, we tested whether overexpression of plasma membrane-localized PBS1TuMV would enhance RPS5 activation by TuMV. Significantly, over-expressing the PBS1TuMV decoy protein conferred complete resistance to TuMV when delivered by either Agrobacterium or by aphid transmission, showing that RPS5-mediated defense responses are effective against bacterial and viral pathogens. Lastly, we have now extended this PBS1 decoy approach to soybean by modifying a soybean PBS1 ortholog to be cleaved by the NIa protease of soybean mosaic virus (SMV). Transgenic overexpression of this soybean PBS1 decoy conferred immunity to SMV, demonstrating that we can use endogenous PBS1 proteins in crop plants to engineer economically relevant disease resistant traits.

scholarly journals HopA1 Effector from Pseudomonas syringae pv syringae Strain 61 Affects NMD Processes and Elicits Effector-Triggered Immunity

2021 ◽  
Vol 22 (14) ◽  
pp. 7440
Author(s):  
Shraddha K. Dahale ◽  
Daipayan Ghosh ◽  
Kishor D. Ingole ◽  
Anup Chugani ◽  
Sang Hee Kim ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Disease Susceptibility ◽  
Null Mutant ◽  
In Planta ◽  
Host Range Expansion ◽  
Unique System ◽  
Effector Triggered Immunity ◽  
Transcriptomic Changes ◽  
Immune Detection

Pseudomonas syringae-secreted HopA1 effectors are important determinants in host range expansion and increased pathogenicity. Their recent acquisitions via horizontal gene transfer in several non-pathogenic Pseudomonas strains worldwide have caused alarming increase in their virulence capabilities. In Arabidopsis thaliana, RESISTANCE TO PSEUDOMONAS SYRINGAE 6 (RPS6) gene confers effector-triggered immunity (ETI) against HopA1pss derived from P. syringae pv. syringae strain 61. Surprisingly, a closely related HopA1pst from the tomato pathovar evades immune detection. These responsive differences in planta between the two HopA1s represents a unique system to study pathogen adaptation skills and host-jumps. However, molecular understanding of HopA1′s contribution to overall virulence remain undeciphered. Here, we show that immune-suppressive functions of HopA1pst are more potent than HopA1pss. In the resistance-compromised ENHANCED DISEASE SUSCEPTIBILITY 1 (EDS1) null-mutant, transcriptomic changes associated with HopA1pss-elicited ETI are still induced and carry resemblance to PAMP-triggered immunity (PTI) signatures. Enrichment of HopA1pss interactome identifies proteins with regulatory roles in post-transcriptional and translational processes. With our demonstration here that both HopA1 suppress reporter-gene translations in vitro imply that the above effector-associations with plant target carry inhibitory consequences. Overall, with our results here we unravel possible virulence role(s) of HopA1 in suppressing PTI and provide newer insights into its detection in resistant plants.

scholarly journals Overexpression of Pto Induces a Salicylate-Independent Cell Death But Inhibits Necrotic Lesions Caused by Salicylate-Deficiency in Tomato Plants

2002 ◽  
Vol 15 (7) ◽  
pp. 654-661 ◽  
Author(s):  
Jianxiong Li ◽  
Libo Shan ◽  
Jian-Min Zhou ◽  
Xiaoyan Tang
Keyword(s):  
Cell Death ◽  
Disease Resistance ◽  
Pseudomonas Syringae ◽  
Virulent Strain ◽  
Gene Activation ◽  
Cellular Damage ◽  
Minor Role ◽  
Disease Resistance Gene ◽  
Tomato Plants ◽  
Spontaneous Cell Death

Tomato plants overexpressing the disease resistance gene Pto (35S∷Pto) exhibit spontaneous cell death, accumulation of salicylic acid (SA), elevated expression of pathogenesis-related genes, and enhanced resistance to a broad range of pathogens. Because salicylate plays an important role in the cell death and defense activation in many lesion mimic mutants, we investigated the interaction of SA-mediated processes and the 35S∷Pto-mediated defense pathway by introducing the nahG transgene that encodes salicylate hydroxylase. Here, we show that SA is not required for the 35S∷Pto-activated microscopic cell death and plays a minor role in defense gene activation and general disease resistance in 35S∷Pto plants. In contrast, temperature greatly affects the spontaneous cell death and general resistance in 35S∷Pto plants, and high temperature inhibits the cell death. The NahG tomato plants develop spontaneous, unconstrained necrotic lesions on leaves. These lesions also are initiated by the inoculation of a virulent strain of Pseudomonas syringae pv. tomato. However, the NahG-dependent necrotic lesions are inhibited in the NahG/35S∷Pto plants. This inhibition is most pronounced under conditions favoring the 35S∷Pto-mediated spontaneous cell death development. These results indicate that the signaling pathways activated by Pto overexpression suppress the cellular damage that is caused by SA depletion. We also found that ethylene is dispensable for the 35S∷Pto-mediated general defense.

scholarly journals Estradiol-inducible AvrRps4 expression reveals distinct properties of TIR-NLR-mediated effector-triggered immunity

2020 ◽  
Vol 71 (6) ◽  
pp. 2186-2197 ◽  
Author(s):  
Bruno Pok Man Ngou ◽  
Hee-Kyung Ahn ◽  
Pingtao Ding ◽  
Amey Redkar ◽  
Hannah Brown ◽  
...  
Keyword(s):  
Cell Death ◽  
Cell Surface Receptor ◽  
Leucine Rich Repeat ◽  
Nucleotide Binding Domain ◽  
Hypersensitive Cell Death ◽  
Cell Death Response ◽  
Defence Genes ◽  
Surface Receptor ◽  
Effector Triggered Immunity ◽  
Bacterial Effectors

Abstract Plant nucleotide-binding domain, leucine-rich repeat receptor (NLR) proteins play important roles in recognition of pathogen-derived effectors. However, the mechanism by which plant NLRs activate immunity is still largely unknown. The paired Arabidopsis NLRs RRS1-R and RPS4, that confer recognition of bacterial effectors AvrRps4 and PopP2, are well studied, but how the RRS1/RPS4 complex activates early immediate downstream responses upon effector detection is still poorly understood. To study RRS1/RPS4 responses without the influence of cell surface receptor immune pathways, we generated an Arabidopsis line with inducible expression of the effector AvrRps4. Induction does not lead to hypersensitive cell death response (HR) but can induce electrolyte leakage, which often correlates with plant cell death. Activation of RRS1 and RPS4 without pathogens cannot activate mitogen-associated protein kinase cascades, but still activates up-regulation of defence genes, and therefore resistance against bacteria.

scholarly journals Harpin Inactivates Mitochondria in Arabidopsis Suspension Cells

2004 ◽  
Vol 17 (2) ◽  
pp. 131-139 ◽  
Author(s):  
Maren Krause ◽  
Jörg Durner
Keyword(s):  
Cell Death ◽  
Programmed Cell Death ◽  
Pseudomonas Syringae ◽  
Stress Responses ◽  
Time Course ◽  
Defense Responses ◽  
Ros Generation ◽  
Suspension Cells ◽  
Mitochondrial Functions ◽  
Arabidopsis Cells

Harpin is a well-known proteinaceous bacterial elicitor that can induce an oxidative burst and programmed cell death in various host plants. Given the demonstrated roles of mitochondria in animal apoptosis, we investigated the effect of harpin from Pseudomonas syringae on mitochondrial functions in Arabidopsis suspension cells in detail. Fluorescence microscopy in conjunction with double-staining for reactive oxygen species (ROS) and mitochondria suggested co-localization of mitochondria and ROS generation. Plant defense responses or cell death after pathogen attack have been suggested to be regulated by the concerted action of ROS and nitric oxide (NO). However, although Arabidopsis cells respond to harpin treatment with NO generation, time course analyses suggest that NO generation is not involved in initial responses but, rather, is a consequence of cellular decay. Among the fast responses we observed was a decrease of the mitochondrial membrane potential Δψm and, possibly as a direct consequence, of ATP production. Furthermore, treatment of Arabidopsis cells with harpin protein induced a rapid cytochrome C release from mitochondria into the cytosol, which is regarded as a hallmark of programmed cell death or apoptosis. Northern and DNA array analyses showed strong induction of protecting or scavenging systems such as alternative oxidase and small heat shock proteins, components that are known to be associated with cellular stress responses. In sum, the presented data suggest that harpin inactivates mitochondria in Arabidopsis cells.

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