October
2000
, Volume
13
, Number
10
Pages
1,130
-
1,138
Authors
Sergio H.
Brommonschenkel
,
1
,
2
Amy
Frary
,
1
Anne
Frary
,
1
and
Steven D.
Tanksley
1
Affiliations
1Department of Plant Breeding, Department of Plant Biology, 252 Emerson Hall, Cornell University, Ithaca NY 14853 U.S.A.; 2Departamento de Fitopatologia/BIOAGRO, Universidade Federal de Viçosa, 36571-000 Viçosa-MG Brazil
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RelatedArticle
Accepted 8 June 2000.
Abstract
We used a positional cloning approach to isolate the Sw-5 disease resistance locus of tomato. Complementation experiments with overlapping cosmid clones enabled us to demonstrate that Sw-5 is a single gene locus capable of recognizing several tospovirus isolates and species. Analysis of the predicted Sw-5 protein suggests that it is a cytoplasmic protein, with a potential nucleotide binding site (NBS) domain and a C-terminal end consisting of leucine-rich repeats (LRRs). Based on its structural features, Sw-5 belongs to the class of NBS-LRR resistance genes that includes the tomato Mi, I2, and Prf genes; the Arabidopsis RPM1 gene; and the plant potato virus X resistance gene Rx. The overall similarity between the Sw-5 and Mi proteins of tomato suggests that a shared or comparable signal transduction pathway leads to both virus and nematode resistance in tomato. The similarity also supports the hypothesis that Sw-5 provides resistance via a hypersensitive response. Sw-5 is a member of a loosely clustered gene family in the telomeric region of chromosome 9. Members of this family map to other regions of chromosome 9 and also to chromosome 12, where several fungal, virus, and nematode genes have been mapped, suggesting that paralogs of Sw-5 may have evolved to provide different resistance specificities.
JnArticleKeywords
Additional keywords:
Lycopersicon esculentum,
map-based cloning,
Tomato spotted wilt virus,
TSWV.
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ArticleCopyright
© 2000 The American Phytopathological Society