Transient expression and oil body targeting of an Arabidopsis oleosin-GUS reporter fusion protein in a range of oilseed embryos

Abstract

An Arabidopsis oleosin gene including 860 bp of promoter as well as coding sequence was fused to the reporter, β-glucuronidase (GUS). In transient expression assays following particle bombardment, the Arabidopsis gene in both transcriptional and translational fusions with GUS was functional in a range of oilseed embryos as determined histochemically and fluorimetrically. Significantly, upon homogenization and separation into cytoplasmic and oil body fractions, the complete oleosin-GUS fusion was found to be targeted to the oil bodies in all of the heterologous species tested including canola, flax, soybean, sunflower, safflower, cotton, castor bean, coriander as well as the monocot, corn. The utilization of oleosin protein fusions for recombinant protein expression should be applicable to this wide range of oilseed crops. Additionally, the method of transient expression subcellular targeting should be useful in determining structural motifs controlling intracellular trafficking of these proteins.