TMV resistance gene N homologues are linked to Synchytrium endobioticum resistance in potato |
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Authors: | R Hehl E Faurie J Hesselbach F Salamini S Whitham B Baker C Gebhardt |
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Institution: | Institut für Genetik, Technische Universit?t Braunschweig, Spielmannstr. 7, D-38106 Braunschweig, Germany Fax:+49?531?391?5765 E-mail:?rh@alpha.bio.nat.tu-bs.de, DE Max-Planck-Institut für Züchtungsforschung, Carl von Linne Weg 10, 50829 Cologne, Germany, DE USDA/ARS-UC Berkeley, Plant Gene Expression Center, 800 Buchanan St., Albany, CA 94710, USA, US
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Abstract: | The fungus Synchytrium endobioticum, the causal agent of potato wart disease, is subject to world-wide quarKantine regulations due to the production of persistent
resting spores and lack of effective chemical control measures. The selection of Synchytrium-resistant potato cultivars may be facilitated by using markers closely linked with a resistance gene or by transferring a
cloned gene for resistance into susceptible cultivars. Sen1, a gene for resistance to Synchytrium endobioticum race 1, was localized on potato chromosome XI in a genomic region which is related to the tobacco genome segment harbouring
the N gene for resistance to TMV. Using N as probe, we isolated homologous cDNA clones from a Synchytrium-resistant potato line. The N-homologous sequences of potato identified by RFLP mapping a family of resistance gene-like sequences closely linked with
the Sen1 locus. Sequence analysis of two full-length N-homologous cDNA clones revealed the presence of structural domains associated with resistance gene function. One clone (Nl-25)
encodes a polypeptide of 61 kDa and harbours a Toll-interleukin like region (TIR) and a putative nucleotide binding site (NBS).
The other clone (Nl-27) encodes a polypeptide of 95 kDa and harbours besides the TIR and NBS domains five imperfect leucine-rich
repeats (LRRs). Both clones have at their amino terminus a conserved stretch of serine residues that was also found in the
N gene, the RPP5 gene from Arabidopsis thaliana and several other resistance gene homologues, suggesting a function in the resistance response. Cloning of the disease resistance
locus based on map position and the establishment of PCR-based marker assays to assist selection of wart resistant potato
genotypes are discussed.
Received: 4 August 1998 / Accepted: 14 August 1998 |
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Keywords: | Plants Disease resistance Host-pathogen interaction Synchytriumendobioticum Potato |
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