Development of a locus-specific, co-dominant SCAR marker for assisted-selection of the Sw-5 (Tospovirus resistance) gene cluster in a wide range of tomato accessions

作者：Dianese Erico C; de Fonseca Maria Esther N; Goldbach Rob; Kormelink Richard; Inoue Nagata Alice K; Resende Renato O^*; Boiteux Leonardo S

来源：Molecular Breeding, 2010, 25(1): 133-142.

DOI：10.1007/s11032-009-9313-8

• Sw-5
• Tospovirus
• Resistance
• Marker
• PCR
• Selection

The best levels of broad-spectrum Tospovirus resistance reported in tomatoes thus far are conferred by the Sw-5 locus. This locus contains at least five paralogues (denoted Sw-5a through Sw-5e), of which Sw-5b represents the actual resistance gene. Here we evaluated a panel of seven PCR primer pairs matching different sequences within a genomic region spanning the Sw-5a and Sw-5b gene cluster. Primer efficiency evaluation was done employing tomato isolines with and without the Sw-5 locus. One primer pair produced a single and co-dominant polymorphism between susceptible and resistant isolines. Sequence analysis of these amplicons indicated that they were specific for the Sw-5 locus and their differences were due to insertions/deletions. The polymorphic SCAR amplicon encompass a conserved sequence of the promoter region of the functional Sw-5b gene, being located in the position -31 from its open reading frame. This primer pair was also evaluated in field assays and with a collection of accessions known to be either susceptible or resistant to tospoviruses. An almost complete correlation was found between resistance under greenhouse/field conditions and the presence of the marker. Therefore, this primer pair is a very useful tool in marker-assisted selection systems in a large range of tomato accessions.

• 出版日期2010-1