Genetic Resources of Olea europaea L. in the Garda Trentino Olive Groves Revealed by Ancient Trees Genotyping and Parentage Analysis of Drupe Embryos.

The area of the Garda Lake within the Trentino province (north of Italy) is the northernmost part of Europe where the Mediterranean species Olea europaea L. is traditionally cultivated. 'Casaliva' is claimed as the main variety traditionally grown in the Garda Trentino area (GT) from which a world renowned niche extra virgin olive oil is produced. Since a dominant presence of 'Casaliva' would link the fruit set success and yield to a self-pollination compatibility system, a deep genetic survey of the olive tree population in the GT has been performed with the aim of establishing the actual varietal composition and of understanding from which pollen donor the 'Casaliva' olives originate. Forty-four different genetic profiles were observed among the 205 leaf samples collected from 106 ancient trees through the analysis of 20 nuclear microsatellite markers. The varietal composition in modern orchards was also explored and the vast majority of the additional 151 trees analyzed showed the same genotype as the ancient accessions of 'Casaliva'. The results support the long historical link of 'Casaliva' with the GT and, besides a high varietal homogeneity, they also revealed the presence of olive genetic resources essential to fruit production. In fact, the parentage analysis of 550 embryos from drupes of 'Casaliva' evidenced that a cross-fertilization system is favored and a list of candidate cultivars most suitable as local pollinizers of 'Casaliva' was identified.

Cryopreservation of olive embryogenic cultures.

The aim of this work was to optimize a protocol for the cryopreservation of embryogenic cultures of olive (Olea europaea L.). Exposure time to loading solution and PVS2 significantly influenced the regrowth rate of both organized and non-organized tissues. Organized tissues were more sensitive to prolonged treatments with vitrification solutions compared to non-organized tissues. Three cryopreservation protocols were compared using non-organized tissues: the "classical" vitrification protocol, an ultra-fast freezing method using droplet vitrification on aluminium foil strips and a "classical" slow freezing method (1 degree C per min). The best results were obtained using the droplet vitrification method after a 60 min dehydration period with PVS2. Under these conditions, all cryopreserved cultures showed renewed embryogenesis six weeks after thawing. A long-term (7-8 weeks) sucrose preculture had a significant effect on the initial response of the cultures, allowing particularly to protect cells against the toxic effects of the vitrification solution.

Metal ion uptake from aqueous solution by olive stones: a carbon-13 solid-state nuclear magnetic resonance and potentiometric study.

The use of biomasses that result from the agriculture and food industries in removing heavy metals from wastewaters is attracting increasing interest. We present a joined potentiometric and cross polarization magic angle spinning (CP-MAS) carbon-13 (13C) nuclear magnetic resonance (NMR) study on the interaction of olive stones with copper(II), nickel(II), and cadmium(II). The potentiometric measurements allow both to distinguish two kind of basic sites in the olive stones and to postulate the coordination models for the three studied metals. The NMR spectral analysis allows the attribution of the different signals to the components of the olive stone matrix. A comparison of CP-MAS 13C NMR spectra of the samples after metal treatment suggests a specific complexation between metal ions and hydroxyl groups on guaiacyl and syringyl moieties.

Oleosin gene expression in olive.

To study the spatial and temporal regulation of oleosin gene expression during olive drupe development, a cDNA (OeOLE) was isolated from embryos. The deduced amino acid sequence of 165 amino acid residues exhibits a long central hydrophobic stretch, including the conserved "proline knot" motif. Phylogenetic analysis grouped OeOLE into the class of high (H) molecular weight oleosins. Southern blotting indicated that the gene is represented by 1-2 copies in the olive genome. Transcript analysis revealed that OeOLE is expressed solely in seeds. A similar bell-shaped pattern of expression was observed in both embryos and endosperms. Transcript accumulation starts at late heart embryo stage, reaches maximum levels at mid-torpedo stage and thereafter declines, coinciding the stages of most oil accumulation in those tissues.