Transgenic constructs. pUCEUbi:GFP-NOS, pUCEUbi:TP-GFP-HvGBSSIaΔTP:NOS and pUCEUbi:HvGBSSIa-GFP:NOS constructs. (a) The control vector (pUCEUbi:GFP:NOS) was engineered for constitutive expression of the reporter gene encoding enhanced Green Fluorescent Protein (eGFP). (b) The pUCEUbi:TP-GFP-HvGBSSIaΔTP:NOS and the (c) pUCEUbi:HvGBSSIa-GFP:NOS were designed to overexpress the endogenous barley granular bound starch synthase Ia. HvGBSSIa was fused with GFP. In (b) the GFP was placed after the transit peptide (TP) in GBSSIa. For all constructs, expression was driven by the common maize Ubiquitin promoter. The actual lengths of the individual elements are not drawn to scale.