Biochemical and molecular basis of the synthesis of sunflower seed wax esters

Abstract

Sunfiower seeds are achenes growing as a part of a multiple fiower. They eonsist of an oil rieh eotyledon eovered by a ligneous hull. Sunfiower seed hull eontains a fairly high amount of wax esters (WEs) that proteet the embryo from humidity and pests attaek. These WEs are also present in erude sunfiower oil, eonferring it viseosity and turbidity. They often have to be removed tbrough winterization and aid filtration. Sunfiower WEs are formed for C32 to C56 saturated speeies, formed by CI8 to C32 fatty aeids and aleohols. In the present work we studied the proeess of WE aeeumulation in sunfiower seeds, analyzing its amount and eomposition of along the seed development proeess. Furthermore, we sereened sunfiower genome searehing for genes eandidates responsible of their synthesis. Among them, we found several fatty acid reductases (FAR) and wax synthases (WS) that are expressed in the hull during seed developmento These gene candidates were st.udied in terms of gene expression and subeellular loeation. Once doned, tbese gene.s were expre~sed in yeast ro asseES them as active enzyme and study their substrate speeificity. The eont ribution of the different genes to the synthesis of sunfiower seed \YEs was discussed attending ro substrate specificity and product analysis. T he possible applieation of these genes for the future production of saturated WEs in other species was also considered.