© 2007 Heron Publishing—Victoria, Canada
Discrete roles of a microsomal linoleate desaturase gene in olive identified by spatiotemporal transcriptional analysis
Georgios Banilas (1), Alkis Nikiforiadis (1), Ifigenia Makariti (1), Anastassios Moressis (1, 2) and Polydefkis Hatzopoulos (1, 3)
1. Laboratory of Molecular Biology, Department of Agricultural Biotechnology, Agricultural University of Athens, Iera Odos 75,
118 55 Athens, Greece / 2. Present address: Laboratory of Molecular Neurobiology, Institute of Molecular Biology and Genetics, BSRC ‘Alexander Fleming,’
34 Al. Fleming Street, 166 72 Vari, Greece / 3. Corresponding author (phat@aua.gr) / Received February 27, 2006; accepted June 20, 2006; published online January 2, 2007
Summary
The relative abundance of α-linolenic (α-LeA) compared with linoleic acid is associated with the developmental stage and the
plant species and is proposed to have important physiological effects on both vegetative and reproductive plant development.
The enzymes responsible for catalyzing the conversion of linoleic acid to α-LeA, the ω-3 fatty acid desaturases (FADs), are
localized in the plastid or the endoplasmic reticulum (ER). Here we present the isolation of an ER-type ω-3 FAD gene (OeFAD3) from olive (Olea europaea L.). Expression patterns of OeFAD3 in different seed tissues and mesocarps during olive fruit development showed that its contribution to olive oil biosynthesis
and modification is minimal. Regulation of OeFAD3 differed from that of its plastidial counterpart, being preferentially expressed in proliferating tissues, in concert with
the active membrane biogenesis required for cell division. Trienoic acid-deficient Arabidopsis mutants are male sterile, because α-LeA-derived jasmonic acid (JA) is required for pollen development. However, the upregulation
of OeFAD3 in different pistil tissues, particularly in vascular bundles and ovaries, rather than in anthers, implies a critical role
of α-LeA in female gametophyte development in olive, corroborating results from JA-defective tomato mutants that are female
sterile but not male sterile.
Keywords:
drupe development, fatty acids, flower, lipids, Olea europaea, olive oil.
