**5. Acknowledgment**

76 Genetic Diversity in Plants

Owen *et al.*, 2004). In spite of its economical importance and metabolic peculiarities, very few data are available on gene sequences controlling the main metabolic pathways. Particular attention has been paid to the genes encoding the key enzymes involved in fatty acid biosynthesis, fatty acid modification, triacylglycerol synthesis, and fat storage

In recent years, much attention has turned to the olive fruit. In this contest, the parallel sequencing of different fruit cDNA collections has provided large scale information about the structure and putative function of gene transcripts accumulated during fruit

A nuclear gene, named *OeCHLP* (*Olea europaea* GERANYLGERANYL REDUCTASE was isolated and characterizated by Bruno *et al.,* (2009). This gene encodes a chloroplastic enzyme involved in the formation of phytolic side chain of tocopherols chlorophyll, and plastoquinones. In olive fruits *OeCHLP* gene expression was enhanced in dark fruit very likely in relation to the increase in mature fruits of the level of total tocopherols suggesting a role in the synthesis of the antioxidant. It is noteworthy that the variations in gene transcript levels that occurred during the ripening of olive fruits depend on the genotype analyzed (Muzzalupo *et al.,* 2011). In this contest, in olive fruits tocopherols confer not only nutritional value (Valk and Hornstra, 2000), but also contribute to product stability and post harvesting shelf life (Goffman and Bohme, 2001) by protecting storage oil from oxidative damage (Sattler *et al.,* 2004). *OeCHLP* was also detected in fruits attacked by *Bactrocera oleae*  pathogen as well as in fruits wounded by needle suggesting a role in protection mechanisms related to cell damage and oxidative burst induced by pathogen (photo 8 and 10) (Ebel,

Although many efforts have been made in the last years, genome studies in *Olea europaea* L. are currently behind those of other crops. Several groups have started to work on the olive genome sequencing and, thanks to the rapid development of the new sequencing technologies; hopefully soon the complete sequence of olive genome will be available. Identification of all genes within a species permits an understanding of how important agronomic traits are controlled, knowledge of which can be directly translated into crop

The availability of reliable genotype data of olive varieties and oils deriving from them, in publicly accessible curate and regularly update databases will be the challenge for the next few years. Recent advances in DNA sequencing technology are radically changing biological and biomedical research and will have a major impact on crop improvement. The new information on genome sequence will be very useful to identify genes involved in agronomical traits that could be used to improve the nutritional characteristics and the productivity of this crop. A possible application could be, for example, the studies of molecular mechanisms of drought and salinity tolerance of olive, in order to improve the cultivation of this important fruit crop also in the most arid and semiarid areas of the world. The knowledge of genome nucleotide sequences also could be useful to identify new sequence polymorphisms, which will be very useful in the development of many new variety-specific molecular markers and in the implementation of more efficient protocols for

(Hatzopoulos *et al.,* 2002; De la Rosa *et al.,* 2003; Banilas *et al.,* 2005).

development (Alagna *et al.*, 2009).

1998; Klessig *et al.,* 2000; Bruno *et al.*, 2009).

tracking and protect olive oil origin.

**4. Conclusion** 

improvement.

The chapter has been possible thanks to the contribution of time, energy and expertise by many individuals of CRA-OLI and Dep. Ecology of UNICAL. The authors would like to take this opportunity to acknowledge their generosity. The authors thank the International Treaty on Plant Genetic Resources for Food and Agriculture - Plant Genetic Resources (RGV-FAO) for financial support.
