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Aubergine (eggplant) is susceptible to fungal wilts caused by Fusarium oxysporum f. sp. melongenae (Fom) and Verticillium dahliae (Vd). Wild and allied relatives represent a good source of resistance, and introgression lines (ILs) have been obtained through introgression of the Rfo-sa1 locus conferring resistance to Fusarium oxysporum from Solanum aethiopicum into cultivated aubergine. In this work, a deep phenotype characterization was performed according to two parameters: progression of symptoms along the stem and disease severity in leaves. This analysis showed that the Fom-resistant ILs carrying introgression of the Rfo-sa1 locus displayed significantly improved tolerance to Verticillium attack after a preliminary inoculation with F. oxysporum. This positive effect was particularly evident when Verticillium inoculation was performed simultaneously or after Fusarium inoculation. Transcript profiling carried out using a combination of suppression subtractive hybridization ( SSH), microarray and qRT-PCR analyses of roots inoculated with selected combinations of fungal pathogens enabled the identification of 164 differentially expressed genes between inoculated and uninoculated plants or between different stages after pathogen infection. Overall, the results highlighted a number of candidate genes putatively involved in early defence responses or signalling pathways activated upon infection of aubergine with either Fom and/or Vd, and thus leading to a broad Rfo-sa1-mediated tolerance against both these wilt pathogens. [ABSTRACT FROM AUTHOR]

The so-called Rosa (= pink) tomatoes, which are typically grown in the Southern Italian area, are characterized by the pink colour of the fruit, due to the gene y, colourless fruit skin. In a preliminary survey, it was found that among these Rosa tomatoes there were some ‘Rosa di Sorrento’ local landraces showing resistance to Verticillium wilt (race 1). In tomato, 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. The development of two new markers for Ve1 and Ve2, based respectively on selective allele-specific PCR amplification and on a PCR amplification followed by enzymatic restriction, is reported. These two markers allow the identification of both allelic forms at the Ve loci and they are of potential interest for use in marker-assisted selection. Furthermore, ‘Rosa di Sorrento’-resistant lines have the same resistance alleles as those found in the Ve-resistant cultivars. [ABSTRACT FROM AUTHOR]

A modified gene of Bacillus thuringiensis var. Tolworthi (Bt), encoding a coleopteran insect-specific CryIIIB toxin, was transferred via Agrobacterium tumefaciens to the female parent of the eggplant commercial F1 hybrid ‘Rimina’. One-hundred and fifty eight transgenic plants were regenerated and tested by PCR and NPTII expression assays. The presence of the CryIIIB toxin in leaf extracts was demonstrated in 57 out of 93 transgenic plants tested by DAS-ELISA assay. High Bt-expressing plants contained a 74-kDa protein cross-reacting with serum anti-CryIIIB toxin. Twenty three out of 44 S. melongena plants tested by insect bioassay showed significant insecticidial activity on neonate larvae of Colorado Potato Beetle (CPB). The Bt transgene and the toxic effect on CPB larvae were transmitted to progenies derived by selfing. Thus, transgenic Bt eggplants represent a very effective means of CPB pest control. [ABSTRACT FROM AUTHOR]

An assay based on electrolyte leakage (LEA) from callus tissue of Solanum spp. treated with culture filtrates of Verticillium dahliae was useful for screening eggplant genotypes for resistance to Verticillum wilt. Loss of electrolytes from the most resistant genotypes was significantly lower than that from the susceptible genotypes when callus tissue was incubated with a 10% filtrate solution of the virulent isolate 122. No difference was detected with filtrate solutions of the avirulent isolate 809 of the fungus. Among the tested genotypes. the S. melongena lines CCR3 and SM 19/14 and the wild species S. Torvum were the most resistant in the glasshouse tests and released the smallest amounts of electrolytes. The most susceptible cultivars, Lunga Violetta and Giant of China, produced the greatest leakage of electrolytes. LEA performed on stem segments failed to distinguish between susceptible and resistant genotypes of eggplant. [ABSTRACT FROM AUTHOR]