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 ◽  
...  

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.

2018 ◽  
Author(s):  
Matthew Helm ◽  
Mingsheng Qi ◽  
Shayan Sarkar ◽  
Haiyue Yu ◽  
Steven A. Whitham ◽  
...  

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.


2020 ◽  
Vol 33 (7) ◽  
pp. 932-944 ◽  
Author(s):  
Sarah E. Pottinger ◽  
Aurelie Bak ◽  
Alexandra Margets ◽  
Matthew Helm ◽  
Lucas Tang ◽  
...  

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.


2020 ◽  
Author(s):  
Sarah E. Pottinger ◽  
Aurelie Bak ◽  
Alexandra Margets ◽  
Matthew Helm ◽  
Lucas Tang ◽  
...  

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.


Plants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 888
Author(s):  
Hobin Kang ◽  
Quang-Minh Nguyen ◽  
Arya Bagus Boedi Iswanto ◽  
Jong Chan Hong ◽  
Saikat Bhattacharjee ◽  
...  

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.


2015 ◽  
Vol 28 (6) ◽  
pp. 675-688 ◽  
Author(s):  
Masayoshi Hashimoto ◽  
Ken Komatsu ◽  
Ryo Iwai ◽  
Takuya Keima ◽  
Kensaku Maejima ◽  
...  

Systemic necrosis is one of the most severe symptoms caused by plant RNA viruses. Recently, systemic necrosis has been suggested to have similar features to a defense response referred to as the hypersensitive response (HR), a form of programmed cell death. In virus-infected plant cells, host intracellular membrane structures are changed dramatically for more efficient viral replication. However, little is known about whether this replication-associated membrane modification is the cause of the symptoms. In this study, we identified an amino-terminal amphipathic helix of the helicase encoded by Radish mosaic virus (RaMV) (genus Comovirus) as an elicitor of cell death in RaMV-infected plants. Cell death caused by the amphipathic helix had features similar to HR, such as SGT1-dependence. Mutational analyses and inhibitor assays using cerulenin demonstrated that the amphipathic helix–induced cell death was tightly correlated with dramatic alterations in endoplasmic reticulum (ER) membrane structures. Furthermore, the cell death–inducing activity of the amphipathic helix was conserved in Cowpea mosaic virus (genus Comovirus) and Tobacco ringspot virus (genus Nepovirus), both of which are classified in the family Secoviridae. Together, these results indicate that ER membrane modification associated with viral intracellular replication may be recognized to prime defense responses against plant viruses.


2021 ◽  
Author(s):  
Bowen Li ◽  
Adhimoolam Karthikeyan ◽  
Liqun Wang ◽  
Jinlong Yin ◽  
Tongtong Jin ◽  
...  

Abstract Background: Soybean mosaic virus (SMV) is the most devastating pathogen of soybean. MicroRNAs (miRNAs) are a class of non-coding RNAs (21-24 nucleotides) and play important roles in regulating defense responses against pathogens. However, miRNA's response to SMV in soybean is not as well documented. Result: In this study, we analyzed 18 miRNA libraries, including three biological replicates from two soybean lines (Resistant and susceptible lines to SMV strain SC3 selected from the near-isogenic lines of Qihuang No. 1× Nannong1138-2) after virus infection at three different time intervals (0 dpi, 7 dpi, and 14 dpi). A total of 1,092 miRNAs, including 608 known miRNAs and 484 novel miRNAs were detected. Differential expression analyses identified the miRNAs responded during soybean-SMV interaction. Then, miRNAs potential target genes were predicted via data mining, and functional annotation was done by Gene Ontology (GO) analysis. Eventually, the expression patterns of several miRNAs validated by quantitative real-time PCR analysis are consistent with sequencing results. Conclusion: We have identified a large number of miRNAs and their target genes and also functional annotations. Our study provides additional information on soybean miRNAs and an insight into the role of miRNAs during SMV-infection in soybean.


2006 ◽  
Vol 19 (3) ◽  
pp. 304-312 ◽  
Author(s):  
Li Wang ◽  
Alan Eggenberger ◽  
John Hill ◽  
Adam J. Bogdanove

Soybean mosaic virus (SMV) was adapted for transgene expression in soybean and used to examine the function of avirulence genes avrB and avrPto of Pseudomonas syringae pvs. glycinea and tomato, respectively. A cloning site was introduced between the P1 and HC-Pro genes in 35S-driven infectious cDNAs of strains SMV-N and SMV-G7. Insertion of the uidA gene or the green fluorescent protein gene into either modified cDNA and bombardment into primary leaves resulted in systemic expression that reflected the pattern of viral movement into uninoculated leaves. Insertion of avrB blocked symptom development and detectable viral movement in cv. Harosoy, which carries the Rpg1-b resistance gene corresponding to avrB, but not in cvs. Keburi or Hurrelbrink, which lack Rpg1-b. In Keburi and Hurrelbrink, symptoms caused by SMV carrying avrB appeared more quickly and were more severe than those caused by the virus without avrB. Insertion of avrPto enhanced symptoms in Harosoy, Hurrelbrink, and Keburi. This result was unexpected because avrPto was reported to confer avirulence on P. syringae pv. glycinea inoculated to Harosoy. We inoculated Harosoy with P. syringae pv. glycinea expressing avrPto, but observed no hypersensitive reaction, avrPto-dependent induction of pathogenesis-related protein 1a, or limitation of bacterial population growth. In Hurrelbrink, avrPto enhanced bacterial multiplication and exacerbated symptoms. Our results establish SMV as an expression vector for soybean. They demonstrate that resistance triggered by avrB is effective against SMV, and that avrB and avrPto have general virulence effects in soybean. The results also led to a reevaluation of the reported avirulence activity of avrPto in this plant.


2004 ◽  
Vol 17 (2) ◽  
pp. 131-139 ◽  
Author(s):  
Maren Krause ◽  
Jörg Durner

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.


Bragantia ◽  
2003 ◽  
Vol 62 (1) ◽  
pp. 19-27 ◽  
Author(s):  
Manoel Albino Coelho de Miranda ◽  
Nelson Raimundo Braga ◽  
André Luiz Lourenção ◽  
Fernando Toledo Santos de Miranda ◽  
Sandra Helena Unêda ◽  
...  

A cultivar de soja IAC-23 foi obtida pelo método genealógico modificado, a partir do cruzamento BR-6 X IAC 83-23, tendo sido avaliada com a designação IAC 93-345, em 14 ambientes, nos Estados de São Paulo e de Minas Gerais. Os ensaios finais foram desenvolvidos em Conceição das Alagoas (MG), Mococa (SP) e Campinas (SP), em 1994/95; em Conceição das Alagoas, Campinas, Morro Agudo (SP) e Tarumã (SP) em 1995/96; Conceição das Alagoas, Mococa, Campinas, Morro Agudo, Tarumã e Ribeirão Preto (SP), em 1996/97; e em Campinas em 1998/99. Utilizou-se o delineamento de blocos ao acaso, com quatro repetições. Em semeaduras de novembro, esse cultivar precoce, com período juvenil longo, floresceu aos 43 dias, após a semeadura, e suas plantas atingiram 67 cm de estatura. A duração entre a emergência das plântulas e o estádio de maturação (R-8) foi de 106 dias, dentro do grupo de maturação precoce. O rendimento médio de grãos foi de 3.017 kg.ha-1. As plantas na maturação apresentam pubescência marrom e sementes amarelas com hilo marrom. Essa cultivar apresenta resistência às doenças pústula-bacteriana (Xanthomonas campestris pv. glycines), fogo-selvagem (Pseudomonas syringae pv. tabaci), cancro-da-haste (Diaporthe phaseolorum f. sp. meridionalis) e mancha-café ("soybean mosaic virus", SMV). Apresenta também resistência a insetos mastigadores e sugadores, semelhante à cultivar IAC-17 e superior à IAS-5. A produtividade e estabilidade apresentadas pela cultivar IAC-23 sugerem sua indicação para condições edafoclimáticas similares às dos experimentos realizados.


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