Characterization And Expression Pattern Of Geranylgeranyl Hydrogenase Gene In Olea Europaea L.

The geranylgeranyl hydrogenase enzyme reduces free geranylgeranyl diphosphate to phytil diphospfate, providing the side chain to chlorophylls, tocopherols and plastoquinones.(1). Tocopherols and plastoquinones are antioxidant compounds which shield plants from ageing and photo-oxidative processes (2). They also constitute vitamins E and K, respectively, and affect nutritional value of fruits, their stability in the post-harvesting cold chain and shelf live. Therefore, the gene involved the synthesis of these compounds, such as CHLP may be useful tools as expressed markers in breeding programmes or genetically manipulated to improve traits of fruit quality. (3). In the present work gene coding for CHLP has been characterized in Olea europea L. as an ORF of 1395bp, encoding a deduced polypeptide of 464amino acid. The deduced protein OeCHLP was 51,2 kDa and exhibited the maximal identity with Nicotiana tabacum. Gene expression analysis by RT-PCR showed that OeCHLP transcripts are present in photosintetic organs such as green fruits and leaves at different developmental stage. Notably, gene expression was detected also in prefloral buds suggesting a gene function not exclusively linked to photosynthesis. According to this hypothesis, analyses by semi-quantitative RT-PCR showed that transcripts levels of OeCHLP increase in fruit injured by pathogens as compared to intact ones. These results are discussed in view of OeCHLP function in defense response mechanism.