Pyramiding Ty‐2 and Ty‐3 genes for resistance to monopartite and bipartite tomato leaf curl viruses of India

Abstract

Breeding resistance to whitefly‐transmitted begomoviruses is an important goal of tomato breeding programmes worldwide. So far, resistance to begomoviruses in tomato has been achieved using wild species, and at least five resistance genes (Ty genes) have been studied. The present study was undertaken to combine Ty‐2 and Ty‐3 and to determine the effect of pyramiding on infection of tomato by three diverse begomovirus species. The diagnostic ability of the markers linked to Ty genes was assessed and marker‐assisted selection was used to develop pyramided tomato lines from the crosses between Ty stocks. Five stable pyramided tomato lines that differ in fruit morphology and yield potential were developed. The horticultural performance of pyramided lines in field trials showed that the yield and horticultural traits are well maintained in the plants. The response of these lines was assessed using agroinoculation and field tests in a disease hotspot. The pyramided lines and Ty‐3‐carrying lines exhibited a high level of resistance to the monopartite and two bipartite begomoviruses tested. The pyramided tomato lines developed in this study could be important genetic resources for sustainable tomato production in areas affected by tomato leaf curl virus disease. The combined results of disease resistance tests also showed that Ty‐3 is critical for achieving broad‐spectrum resistance. The limitations of relying on a single gene and the importance of pyramiding are discussed in the light of available evidence on frequent recombination in begomoviruses.

A Novel Strain of Tomato Leaf Curl New Delhi Virus Has Spread to the Mediterranean Basin

“…Nevertheless, if efficient spread to tomato occurs, here we showed that the Ty-1 gene already deployed for the control TYLCD-associated viruses [49] seems to provide resistance to ToLCNDV, even for the isolate from India that causes severe infections in susceptible tomatoes. Moreover, other gene combinations have been reported to provide effective resistance to ToLCNDV infections in tomato [50,51]. …”

Resistance-Gene-Mediated Defense Responses against Biotic Stresses in the Crop Model Plant Tomato

“…Unlike Rx-mediated resistance that results in extreme resistance (ER) against potato virus X [110], TYLCV mediated resistance results in virus tolerance rather than immunity. Functional Ty-1/Ty-3-like alleles are also present in several other S. chilense wild type tomato accessions, shown by fine mapping and VIGS [111]. Additionally, the DFDGD catalytic domain of the Ty-1and Ty-3 genes is conserved among Solanum species [111].…”

“…Functional Ty-1/Ty-3-like alleles are also present in several other S. chilense wild type tomato accessions, shown by fine mapping and VIGS [111]. Additionally, the DFDGD catalytic domain of the Ty-1and Ty-3 genes is conserved among Solanum species [111]. In a recent study, Ty-2 and Ty-3 genes were used to develop a series of R-gene pyramided tomato lines and the linked markers were evaluated for their diagnostic value and utility in pyramiding Ty genes [112].…”

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

“…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.…”