Expression of Potato Virus X Resistance Gene Rx in Potato Leaf Protoplasts

Adams, Sally E.; Jones, R. A. C.; Coutts, Robert H.A.

doi:10.1099/0022-1317-67-11-2341

Cited by 44 publications

(24 citation statements)

References 23 publications

(33 reference statements)

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“…There is no question that components of the Rx-mediated response and the response of G. globosa are distinct: Rxmediated resistance blocks virus accumulation in the inoculated cell (Adams et al, 1986;Saladrigas et al, 1990; Tavantzis, 1990; Kohm et al, 1993), whereas on G. globosa there is evidently accumulation of virus in the inoculated cell and the surrounding area (Figures 1 and 3). However, the nature of in potato carrying Rxacln or in G. globosa if the PVX recognition component is a homolog of Rx.…”

Section: Discussionmentioning

confidence: 99%

“…The other example involves the coat protein of PVX, which is an avirulence determinant on potato carrying the Rx gene Kohm et al, 1993). The resistanceconferred by Rx leads to suppression of virus multiplication in the inoculated cell (Adams et al, 1986;Saladrigas et al, 1990;Kohm et al, 1993) but under most conditions there is no obvious HR. This type of resistance has been referred to as extreme resistance (Tozzini et al, 1991).…”

Section: Introductionmentioning

confidence: 99%

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Functionally Homologous Host Components Recognize Potato Virus X in Gomphrena globosa and Potato.

Goulden

Baulcombe

1993

Plant Cell

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All known isolates of potato virus X (PVX), with the exception of a South American isolate PVXHB, induce an extreme resistance response on potato carrying the Rx gene and elicit the production of necrotic lesions on Gomphrena globosa: PVXHB establishes systemic infection on Rx genotypes of potato and infects the inoculated leaf of G. globosa without lesion formation. Previously, we have shown that the Rx-mediated resistance is affected by a feature of the coat protein that depends on the presence of a threonine residue at position 121 in the coat protein of PVXcp4 and that the resistance is an induced response expressed in protoplasts of potato with the Rx genotype. In this study, we provide evidence, based on the analysis of PVXcp4/PVXHB hybrids, that the elicitation of lesions on 0. globosa also requires the presence of a threonine residue at position 121 of the viral coat protein. The lesion-forming phenotype was not associated with the ability of the viral isolate to accumulate in the infected plant. We therefore propose that there is a homologous component of both potato carrying Rx and G. globosa that interacts with a feature of the PVX coat protein and, following the interaction, activates an induced response in the plant cell.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Functionally Homologous Host Components Recognize Potato Virus X in Gomphrena globosa and Potato.

Goulden

Baulcombe

1993

Plant Cell

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“…Rx is able to condition extreme resistance to PVX in the absence of cell death (Adams et al, 1986). To assess each variant's ability to confer viral resistance, we agroinfiltrated the various P Rx :Rx constructs together with an infectious PVX:GFP clone .…”

Section: Molecular Dissection Of the Rx Nb-arc Domainmentioning

confidence: 99%

“…It is also interesting that whereas the CP-mediated HR responses of wild-type Rx and RR-GRR do not differ, RR-GRR cannot mediate extreme resistance in a transient virus resistance assay (see Supplemental Figure 2 online). Signal amplification through an iterative mechanism might explain the ability of some R genes, including Rx, to mediate extreme resistance to viruses (Adams et al, 1986;Kang et al, 2005). Given the differences observed between Bs2, Rx, and Rx/GPA2 chimeras, this characteristic may vary among R proteins, attributable either to intrinsic differences in the R proteins themselves or to differences in the strength of Avr recognition.…”

Section: Role Of Cp-mediated Disruption Of the Lrr-arc Interactionmentioning

confidence: 99%

Distinct Domains in the ARC Region of the Potato Resistance Protein Rx Mediate LRR Binding and Inhibition of Activation

2006

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Plant nucleotide binding and leucine-rich repeat (NB-LRR) proteins contain a region of homology known as the ARC domain located between the NB and LRR domains. Structural modeling suggests that the ARC region can be subdivided into ARC1 and ARC2 domains. We have used the potato (Solanum tuberosum) Rx protein, which confers resistance to Potato virus X (PVX), to investigate the function of the ARC region. We demonstrate that the ARC1 domain is required for binding of the Rx N terminus to the LRR domain. Domain-swap experiments with Rx and a homologous disease resistance gene, Gpa2, showed that PVX recognition localized to the C-terminal half of the LRR domain. However, inappropriate pairings of LRR and ARC2 domains resulted in autoactive molecules. Thus, the ARC2 domain is required to condition an autoinhibited state in the absence of elicitor as well as for the subsequent elicitor-induced activation. Our data suggest that the ARC region, through its interaction with the LRR, translates elicitor-induced modulations of the C terminus into a signal initiation event. Furthermore, we demonstrate that physical disruption of the LRR-ARC interaction is not required for signal initiation. We propose instead that this activity can lead to multiple rounds of elicitor recognition, providing a means of signal amplification.

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“…A representative example of the cellular-level virus resistance is Rxmediated resistance against potato virus X (PVX; Bendahmane et al, 1999). Rx, an NB-LRR-type R protein, recognizes the coat protein (CP) of PVX and induces rapid defense signaling reactions, resulting in the inhibition of PVX accumulation at the cellular level (Adams et al, 1986). Tm-1, a recently isolated resistance gene from wild tomato (Solanum habrochaites), strictly inhibits the replication of tomato mosaic virus, a member of the genus Tobamovirus, at the cellular level by inactivating viral RNA-dependent RNA polymerase (Ishibashi et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Lectin-Mediated Resistance Impairs Plant Virus Infection at the Cellular Level

et al. 2012

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Plants possess a multilayered defense response, known as plant innate immunity, to infection by a wide variety of pathogens. Lectins, sugar binding proteins, play essential roles in the innate immunity of animal cells, but the role of lectins in plant defense is not clear. This study analyzed the resistance of certain Arabidopsis thaliana ecotypes to a potexvirus, plantago asiatica mosaic virus (PlAMV). Map-based positional cloning revealed that the lectin gene JACALIN-TYPE LECTIN REQUIRED FOR POTEXVIRUS RESISTANCE1 (JAX1) is responsible for the resistance. JAX1-mediated resistance did not show the properties of conventional resistance (R) protein-mediated resistance and was independent of plant defense hormone signaling. Heterologous expression of JAX1 in Nicotiana benthamiana showed that JAX1 interferes with infection by other tested potexviruses but not with plant viruses from different genera, indicating the broad but specific resistance to potexviruses conferred by JAX1. In contrast with the lectin gene RESTRICTED TEV MOVEMENT1, which inhibits the systemic movement of potyviruses, which are distantly related to potexviruses, JAX1 impairs the accumulation of PlAMV RNA at the cellular level. The existence of lectin genes that show a variety of levels of virus resistance, their targets, and their properties, which are distinct from those of known R genes, suggests the generality of lectin-mediated resistance in plant innate immunity.

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Expression of Potato Virus X Resistance Gene Rx in Potato Leaf Protoplasts

Cited by 44 publications

References 23 publications

Functionally Homologous Host Components Recognize Potato Virus X in Gomphrena globosa and Potato.

Functionally Homologous Host Components Recognize Potato Virus X in Gomphrena globosa and Potato.

Distinct Domains in the ARC Region of the Potato Resistance Protein Rx Mediate LRR Binding and Inhibition of Activation

Lectin-Mediated Resistance Impairs Plant Virus Infection at the Cellular Level

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