Whole genome functional annotation of wild olive-tree (Olea europaea var. sylvestris)

Olive (Olea europaea L.) is an economically-important fruit tree, widely spread in the Mediterranean Basin, and belonging to the family of Oleaceae, order of Lamiales, which includes important members for their essential oils, fragrances and phenolics. The olive tree is a diploid (2n = 2x = 46), predominantly allogamous, and vegetatively-propagated species. The genome of the wild olive-tree (O. europaea var. sylvestris) has been recently sequenced and assembled. Structural annotation revealed 60,214 protein-encoding genes (CDS). For the functional annotation, we adopted a double approach: a BLAST-based approach and a protein-domain search approach (Blast_v2.2.30p.sh and interproscan5.sh). The results were combined on a Blas2Go pro project for further Gene Ontology (GO) analysis and functional description assignments. From the total of 60,214 CDS sequences, 23% fail to obtain a BLAST hit, 4% of the BLASTed sequences without hits with functional information cannot be linked to GO entries and 9% of the sequences with GO mapping does not reach the quality for an annotation assignment. The high percentage of CDS with no BLAST hits would be due to the quality of assembly or structural annotation. Overall, we could assign functional labels to 64% of the input sequences. In addition, the Enzyme Code (EC) and  KEGG analysis allowed the identification of 1,480 EC out of 133 KEGG pathways. These results are similar to the ones obtained from other sequenced plant genomes, using the same approach. Meanwhile, we are developing the olive genome browser, as platform for data visualization (chromosome map, gene structure, repeats, sRNA annotations ) .