ISSN:
1572-9788
Keywords:
bacterial artificial chromosome (BAC)
;
virus resistance
;
TSWV
;
Sw-5
;
resistance gene candidates
;
RGC
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Abstract The Sw-5 gene is a dominantly inherited resistance gene in tomato and functional against a number of tospovirus species. The gene has been mapped on chromosome 9, tightly linked to RFLP markers CT220 and SCAR421. To analyse the Sw-5 locus, a BAC genomic library was constructed of tomato cv. Stevens, homozygous for the Sw-5 gene. The library comprised 18 816 clones with an average insert size of 100 kb, corresponding to two genome equivalents. The library was screened by PCR using primers designed for the CT220 and SCAR421 sequences, resulting in a 250 kb contig of known orientation on the long arm of chromosome 9. Using degenerate primers based on homologous sequences in the nucleotide binding site of resistance gene sequences, three discrete PCR fragments obtained from this contig were cloned and sequenced. Analysis of these fragments revealed a high similarity with numerous resistance genes or resistance gene like sequences. The present data indicate that at least three different resistance gene candidate (RGC) sequences are present in the vicinity of marker CT220, supporting the view that a resistance gene family may be responsible for the unusually broad resistance to tospoviruses conferred by the Sw-5 locus.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1009650424891
Permalink