STUDIO DELLA DIVERSITA' GENETICA IN OLIVO (Olea europea L.)

It is known, that the molecular interaction between plants and herbivores originates both up and down regulation of a large number of genes encoding proteins involved in defense mechanisms and signaling, secondary metabolism, abiotic stress and photosynthesis, beside many genes with unknown functions. (Hermsmeier et al., 2001). Therefore, the study of the variation of the transcripts abundance occurring in infested olive fruit tissue, will provide novel information on olive sequences responding to B. oleae infestation and on their involvement in defence. In this frame an useful experimental approach, is the SSH (Suppression Subtractive Hybridization) technique. We used this strategy in order to isolate differentially expressed olive sequences occurring in infested tissue. In addition, we monitored the expression of up-regulated genes in different olive cultivars. For characterization of differential expressed genes in reaction to the fruit fly, a subtractive library was constructed through Suppression Subtractive Hybridization (SSH) method. The library was constructed subtracting mRNAs from un-attacked fruits of cultivar †˜Moraiolo' from mRNAs isolated from with larval feeding tunnel. Among the 590 clones of the library, 219 were sequenced, having an insert size longer than 200 bp. In order to assign a putative function to the different transcripts, similarity analysis was carried out with tblastx algorithm. Approximately 70% of transcripts showed a significant similarity with coding sequences of different plant species (e-value <0.001) mainly Vitis vinifera; among them 113 sequences had similarity with transcripts coding for known protein and 106 with transcripts coding for unknown protein. Only 48% of the ESTs were classified into functional c