No abstract

DNA markers technology, derived from research in molecular biology and genomics, offers great promise for plant breeding, allowing the "molecular breeding" via marker-assisted selection. Grapevine genomic resources allowed, in recent years, the characterization at molecular level of genes involved in interesting phenotypes such as stenospermocarpic seedlessness, a trait really appreciated by consumers. Recent studies in table grapes revealed that the VvAGL11 gene, member of the D-lineage MADS-box family, controls the ovule identity, and thus potentially playing an important role in stenospermocarpy. Intragenic markers of VvAGL11 have been found and tested for breeding purposes. In the present paper, we describe an in deep assay on a total of 475 genotypes derived by our own grape germplasm and seeded × seedless crosses F1 offspring, to evaluate and verify the "diagnostic" power of VvAGL11 in marker-assisted selection. We found only 8/475 that were seeded and carried the seedless-associated allele in the STS p3_VvAGL11. However, and most importantly, there were no seedless varieties without such allele. We validated the marker as a 100 % effective tool for early negative selection of stenospermocarpy in Vitis vinifera L. crosses.

New Plant Breeding Techniques (NPBTs) protocols have been developed to produce new grape varieties with improved quantitative and qualitative characteristics. Reliable transformation protocols for grapes are based on the generation/induction of embryogenic callus cells that are then transformed. Varieties such as Italia have proven to be very recalcitrant to regeneration via somatic embryogenesis. In this work, the development of a protocol for improved production of embryogenic calluses is described. Two sterilization protocols were tested: (a) a lower active chlorine concentration for a longer time (LS); and (b) a higher chlorine concentration for a shorter time (HS), in combination with the absence or presence of citric acid in the growing substrate in the first growth media. The embryogenic calluses formation in Chardonnay, a cv. with a high embryogenic response, was significantly higher in presence of citric acid in the initial growing substrate regardless of the sterilization protocol. In Aglianico, a cv. with a lower embryogenic response, no significant differences were observed. Instead, in a recalcitrant cv. as Italia, we obtained a 13-fold increase in embryogenic calluses formation performing sterilization of flowers with the HS protocol compared to LS.

Abstract.A number of studies have established that vertical transmission of viruses is an important phenomenon affecting a wide range of viruses, especially as a result of breeding programs. Nevertheless, the presence of virus in a seed, does not always lead to seedling infection. In grapevine, seed transmission has been reported for many nepoviruses, but little is known about the other virus associated diseases such as Leafroll, Rugose wood complex and Fleck diseases, that are considered by Italian legislation on certification of grapevine propagation material, together with infectious degeneration. Thus, the aim of this study is monitoring the virological condition of seedlings obtained by crosses between infected parentals, analyzing the sanitary status of seedlings after the transfer in experimental fields. In this study, 50 progeny plants from three different traditionally crossbreed seeded and seedless table grape cultivars were investigated for the detection of nine grapevine viruses. It was observed that the viral state of parentals was quite compromised, while viruses were not detected in any of the 150 progeny plants, demonstrating that the main grapevine viruses are at low risk for seed transmission. These results could make it possible to reduce the precautions to obtain propagation material free from infectious diseases and also suggest to consider reproduction as a new procedure of sanitation in breeding programs.

Grapes represent a significant source of phenolic compounds known for their health-promoting properties, such as antioxidant capacity on normal cells and prooxidant activity on tumor cells. The genotype highly affects the polyphenolic composition in grapes and, consequently, the nutritional quality of berries. This work aimed to characterize the phenolic composition, the antioxidant, and anticancer activity of grape skin extracts (GSEs) of nine new table grape genotypes selected from a breeding program to obtain new cultivars of seedless table grapes, well adapted to the climatic change and with higher nutraceutical properties. The grape polyphenolic profile was characterized by Ultra-High-Performance Liquid Chromatography/Quadrupole-Time of Flight mass spectrometry analysis. GSE antioxidant activity was determined by the ABTS, DPPH, and ORAC assays; GSE cell growth inhibition test was carried out in the Caco2 human cancer cell line. The nine GSEs showed different flavonoid and non-flavonoid profiles, and all possessed antioxidant activity, with the ‘Aika N.’, ‘Turese N.’, and ‘Egnatia N.’ the most active. As anticancer activity against the tested cancer cell line, ‘Daunia N.’ and ‘Apenestae N.’ showed the EC50 after 24 h of 35.60 µg/mL and 150.91 µg/mL, respectively. The relationship between polyphenolic profile and the antioxidant and anticancer activity of GSE was also investigated. Interestingly, among the different classes of polyphenolics, flavan-3-ols e proanthocyanidins showed the highest positive correlation with the anticancer activity of extracts. These findings can be helpful for the preparation of new extracts for the pharmaceutical and nutraceutical industry and geneticists working in vine breeding programs.