Molecular markers for Ve1 and Ve2 Verticillium resistance genes from tomato italian germplasm and its possible use in the selection of eggplant lines tolerant to Verticillium

In a preliminary survey on tomato italian germplasm, an accession derived from the pink ‘Rosa di Sorrento’ local landrace showed resistance to Verticillium wilt (race 1). In tomato, the resistance to race 1 of V. dahliae and V. albo-atrum is conferred by two strictly associated genes, Ve1 and Ve2, which independently confer resistance to the same pathogen. We developed two new markers for Ve1 and Ve2 on the base of tomato available sequences, based respectively on selective allele-specific PCR amplification and on a PCR amplification followed by enzymatic restriction. These two markers allow the identification of both the allelic forms at the Ve loci and they are of potential interest for the application in marker-assisted selection; furthermore, sequence analysis confirmed that the resistant local “pink” landraces possess the same alleles at the locus Ve1 and Ve2 than that of the most common resistant lines. Verticillium wilt is considered an important limiting factor in the production of eggplant, especially in Asia and Mediterranean areas. Therefore, the main goals of eggplant breeding are not only the development of high-quality genotypes but also the achievement of Verticillium wilt tolerant hybrids. In spite of the huge variability, a lack of resistance traits in eggplant gene pool is still evident. Thus, the release of eggplant cultivars tolerant to the main diseases and pests has been very limited. Although genetic variability related to resistance traits has been found, many of these genetic sources, often, give contrasting results when employed in breeding programs. Among the wild relatives of eggplant Solanum sodomaeum L. (2n=24) (= S. linneanum) has been considered as possible source of resistance. However, the response of the elite lines derived from the introgression of S. sodomaeum genome in S. melongena via sexual hybridization, followed by backcrosses and phenotypic selection, is quantitative, with different level of tolerance/resistance to Verticillium wilt. Many earlier comparative genome analysis have been focused on the collinearity of solanaceae genomes, underlining the chance that the similarity of the genomes of the four main Solanaceous crop make feasible the mapping of conserved resistance genes in these related species. Therefore, the newly developed molecular markers tested in the tomato Italian landraces were tested on S. melongena tolerant lines and on its wild relative; the characterisation of the putative eggplant Ve1 and Ve2 homologous is ongoing.