Analysis of the Resistance-Breaking Determinants of Potato Virus X (PVX) Strain HB on Different Potato Genotypes Expressing Extreme Resistance to PVX

Querci, Maddalena; Baulcombe, David C.; Goldbach, R.W.; Salazar, Francisco

doi:10.1094/phyto-85-1003

Cited by 56 publications

(20 citation statements)

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“…Similarly, Rx genes protect potato plants very efficiently against different strains of PVX (Cockerham 1970). Only isolates of PVX strain group 4 are known to overcome Rx (Moreira et al 1980;Tozzini et al 1994;Querci et al 1995) due to a specific mutation in the viral coat protein (Kavanagh et al 1992), and such isolates have been found only twice outside South America (Ross 1986). The Gro1 locus protects against all known pathotypes of G. rostochiensis (Barone et al 1990), whereas Sen1 for wart resistance is effective only against pathotype 1 of S. endobioticum.…”

Section: Discussionmentioning

confidence: 99%

Marker-assisted combination of major genes for pathogen resistance in potato

et al. 2006

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Closely linked PCR-based markers facilitate the tracing and combining of resistance factors that have been introgressed previously into cultivated potato from different sources. Crosses were performed to combine the Ry adg gene for extreme resistance to Potato virus Y (PVY) with the Gro1 gene for resistance to the root cyst nematode Globodera rostochiensis and the Rx1 gene for extreme resistance to Potato virus X (PVX), or with resistance to potato wart (Synchytrium endobioticum). Marker-assisted selection (MAS) using four PCR-based diagnostic assays was applied to 110 F1 hybrids resulting from four 2· by 4· cross-combinations. Thirty tetraploid plants having the appropriate marker combinations were selected and tested for presence of the corresponding resistance traits. All plants tested showed the expected resistant phenotype. Unexpectedly, the plants segregated for additional resistance to pathotypes 1, 2 and 6 of S. endobioticum, which was subsequently shown to be inherited from the PVY resistant parents of the crosses. The selected plants can be used as sources of multiple resistance traits in pedigree breeding and are available from a potato germplasm bank.

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Section: Discussionmentioning

confidence: 99%

Marker-assisted combination of major genes for pathogen resistance in potato

et al. 2006

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“…This response is not the effect of autoactivation as no cell death occurred after coexpression of the Rx1 constructs with GFP ( Figure 1D). Recognition of the PVX CP by Rx1 was earlier shown to depend on the identity of two amino acid residues in the CP sequence (Querci et al, 1995), and a broadening of Rx1 recognition has been reported for Rx1 LRR mutants (Farnham and Baulcombe, 2006).…”

Section: Rx1 Is Located In Both the Cytoplasm And Nucleusmentioning

confidence: 97%

Nucleocytoplasmic Distribution Is Required for Activation of Resistance by the Potato NB-LRR Receptor Rx1 and Is Balanced by Its Functional Domains

Slootweg¹,

Roosien²,

et al. 2010

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The Rx1 protein, as many resistance proteins of the nucleotide binding-leucine-rich repeat (NB-LRR) class, is predicted to be cytoplasmic because it lacks discernable nuclear targeting signals. Here, we demonstrate that Rx1, which confers extreme resistance to Potato virus X, is located both in the nucleus and cytoplasm. Manipulating the nucleocytoplasmic distribution of Rx1 or its elicitor revealed that Rx1 is activated in the cytoplasm and cannot be activated in the nucleus. The coiled coil (CC) domain was found to be required for accumulation of Rx1 in the nucleus, whereas the LRR domain promoted the localization in the cytoplasm. Analyses of structural subdomains of the CC domain revealed no autonomous signals responsible for active nuclear import. Fluorescence recovery after photobleaching and nuclear fractionation indicated that the CC domain binds transiently to large complexes in the nucleus. Disruption of the Rx1 resistance function and protein conformation by mutating the ATP binding phosphate binding loop in the NB domain, or by silencing the cochaperone SGT1, impaired the accumulation of Rx1 protein in the nucleus, while Rx1 versions lacking the LRR domain were not affected in this respect. Our results support a model in which interdomain interactions and folding states determine the nucleocytoplasmic distribution of Rx1.

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“…It is accepted that PVX strains in respect to the Nx, Nb and Rx host resistance genes show classical ''gene-forgene'' type resistance interactions [20,29] and CP is avirulence (resistance sensitivity) determinants of both the Nx and Rx-mediate resistances [2] whereas movement protein is avirulence determinants of Rx-mediated resistance [15]. Currently, more than one-hundred fifty sequences of the CP gene of PVX and 25 complete genomes are available in GenBank database.…”

Section: Introductionmentioning

confidence: 99%

Population genetic analysis of potato virus X based on the CP gene sequence

Hajizadeh

Sokhandan-Bashir

2017

VirusDis.

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To investigate the genetic variation and molecular evolution of potato virus X (PVX), 87 coat protein (CP) gene sequences were retrieved from GenBank and analyzed. Of the PVX isolates studied, one recombinant isolate (X3) was detected from South America population of the virus. The other isolates belonged to two lineages, Eurasia and America, with the significant F ST value (0.60). Non-synonymous nucleotide diversity to synonymous nucleotide diversity (x = dN/dS) was less than 1 indicating that the CP gene has been under negative selection or neutral evolution. Further analysis showed that all of the codons in both lineages were under negative selection pressure. No significant genetic differentiation was found between Chinese, Indian, Iranian, Japanese, and the UK populations whereas South America population was distinctly differentiated from other populations. Different evolutionary constraints found for the two lineages suggest that possible mutations and genetic drift were important evolutionary forces driving the genetic diversification of PVX population.

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Analysis of the Resistance-Breaking Determinants of Potato Virus X (PVX) Strain HB on Different Potato Genotypes Expressing Extreme Resistance to PVX

Cited by 56 publications

References 0 publications

Marker-assisted combination of major genes for pathogen resistance in potato

Marker-assisted combination of major genes for pathogen resistance in potato

Nucleocytoplasmic Distribution Is Required for Activation of Resistance by the Potato NB-LRR Receptor Rx1 and Is Balanced by Its Functional Domains

Population genetic analysis of potato virus X based on the CP gene sequence

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