Molecular Cloning And Function Characterisation Of A Cytoplasmic Fructose-1, 6-Bisphosphate Aldolase Gene From Coconut (Cocos Nucifera L.)

Cytosolic FBA functions in the sucrose biosynthetic pathway and is also a key enzyme in glycolytic pathways in higher plants. In this paper, a cytoplasmic FBA gene (designated CoFBA1) expressed specifically in the endosperm of coconut was identified and cloned. Prediction analysis suggested that the subcellular location of CoFBA1 was the cytoplasm. Then, CoFBA1 was cloned into the pCAMBIA1300s vector driven by the seed-specific promoter napin to verify the in vivo activity of CoFBA1 in Arabidopsis. Three transgenic lines with different levels of CoFBA1 expression were selected for gene expression, total oil content and fatty acid content analyses. In the three overexpression homozygous transgenic lines, the CoFBA1 gene consistently increased in expression. The lipid content in the three transgenic lines increased by 3.5 - 18% compared to that in WT. The total seed lipid content in the three lines simultaneously exhibited a significant increase (P < 0.01), while no significant difference was detected among the three transgenic lines. Moreover, linolenic acid (C-18:3) and eicosanoic acid (C-20:1) increased significantly in the transgenic lines. It was suggested that CoFBA1 overexpression not only increased the total lipid content but also changed the composition of the fatty acids in the transgenic lines.