Schematic representation of constructs used in the Agrobacterium -mediated transient expression systems. (A) Schematic representation of the expression cassette of intermediate plasmid pBPFΩ7 and the binary plant vector pZP200. (B) Schematic representation of pAn/oS and pKn/oS construct. An/oSAG1: the native and plant-optimized genes (residues 77 to 322, excluding the signal peptide in the N-terminus and the 14 hydrophobic amino acids in the C-terminus) fused to the AP24 osmotin signal peptide sequence in the N-terminus for driving the mature protein to the apoplast. Kn/oSAG1: the native and plant-optimized genes (residues 77 to 322) fused to the AP24 osmotin and an endoplasmic reticulum retention signal peptide sequences (TCTGAGAAAGATGAGCTAT) in the N-terminus and the C-terminus, respectively, for accumulation of the recombinant protein in the RE. 35sCaMVx2: duplicated CaMV 35S promoter; T-nos: nopaline synthase terminator sequence; Ω: translational enhancer sequence; bar: gluphosinate-resistant gene; RB and LB: right and left borders of the T region, respectively; MCS: multiple cloning site.