Recessive Resistance to Tomato yellow leaf curl virus from the Tomato Cultivar Tyking Is Located in the Same Region as Ty-5 on Chromosome 4

Abstract

<jats:p><jats:italic>Tomato yellow leaf curl virus</jats:italic> (TYLCV), a <jats:italic>Begomovirus</jats:italic> in the family Geminiviridae, is an important disease of cultivated tomato (<jats:italic>Solanum lycopersicum</jats:italic> L.) in many parts of the world. Disease is managed primarily by chemical control of the vector, the sweetpotato whitefly, <jats:italic>Bemisia tabaci</jats:italic> (Genn.), and by growing resistant varieties. Resistance derived from the cultivar Tyking is being used in many breeding programs, but the location of resistance factors has not been reported. The breeding lines Fla. 8753 and Fla. 344 both have high levels of resistance to TYLCV derived from ‘Tyking’ and from <jats:italic>S. chilense</jats:italic> accession LA 1938, but none of their parent lines contain any of the known genes <jats:italic>Ty-1</jats:italic> to <jats:italic>Ty-4</jats:italic>. An additional resistance locus, <jats:italic>Ty-5</jats:italic>, was recently identified, and to determine if this locus controls TYLCV resistance in Fla. 8753 and Fla. 344, appropriate segregating populations were analyzed using the <jats:italic>Ty-5</jats:italic> marker, <jats:italic>SlNAC1</jats:italic>. Results show that <jats:italic>SlNAC1</jats:italic> cosegregates with a recessive allele derived from ‘Tyking’. We suggest the gene symbol <jats:italic>ty-5</jats:italic> be used to describe this gene. Mean disease severity of progeny homozygous for either the resistant or susceptible alleles did not equal parental levels of resistance and susceptibility, respectively, suggesting the involvement of an additional gene that is likely derived from LA1938.</jats:p>

The Tomato Yellow Leaf Curl Virus Resistance Genes Ty-1 and Ty-3 Are Allelic and Code for DFDGD-Class RNA–Dependent RNA Polymerases

“…Genetic studies have led to the mapping of five TYLCV resistance/tolerance genes which are being exploited for resistance breeding. These genes have different origins: Ty-2 was introgressed from S. habrochaites , Ty-5 ( ty-5 ) was introgressed from S. peruvianum while Ty-1 , Ty-3 and Ty-4 all originated from different S. chilense accessions [19]–[24]. So far, none of these genes have been cloned and the underlying resistance mechanisms are still unknown.…”

Fine mapping of the tomato yellow leaf curl virus resistance gene Ty-2 on chromosome 11 of tomato

“…Ty - 4 , also derived from S. chilense , was mapped to chromosome 3 (Ji et al 2008). The recessively inherited ty - 5 gene, first identified in the breeding line TY172 and later found in material derived from “Tyking,” was mapped to chromosome 4 (Anbinder et al 2009; Hutton et al 2012). The ty - 5 gene is likely derived from a complex of S. peruvianum accessions (Anbinder et al 2009).…”

Introgression of virus-resistance genes into traditional Spanish tomato cultivars ( Solanum lycopersicum L.): Effects on yield and quality

“…However, this option, which is valid for the F1 hybrid cultivars production, is not a viable option for tomato landraces, because local farmers are in charge of seed production every year. Another option to reduce or eliminate the negative effect of the Ty-1 gene introgression in homozygous state could be the introduction of others genes, as the Ty-2 gene, derived from Solanum habrochaitesderived line H24 (Hanson et al, 2000), the Ty-3 gene (allelic to Ty-1), derived from S. chilense accessions LA2779 and LA1932 (Verlaan et al, 2013), the Ty-4 gene, derived from S. chilense (Ji et al, 2009) or the Ty-5 gene, derived from the cultivar Tyking (Hutton et al, 2012). Recently, Prasanna et al (2015) reported that the Ty-2 and Ty-3 gene pyramiding produces tomato lines with a high level of resistance to the begomoviruses tested, achieving broad-spectrum resistance.…”