Protein expression in plants

A transient expression based method for producing large quantities of a heterologous polypeptide in Nicotiana tabacum comprising the steps of:

• (i) infiltrating a whole plant of Nicotiana tabacum line PM132, seeds of which were deposited under accession number NCIMB 41802 strain with a suspension of the strain of Agrobacterium tumefaciens strain AGL1 or of Agrobacterium tumefaciens strain EHA105 at an OD600 of between 0.1 and 4.0, the strain comprising an expressible nucleotide sequence encoding the heterologous polypeptide;
• and
• (ii) incubating the infiltrated plant for a period of between 5 days and 10 days under conditions that allow expression of the expressible nucleotide sequence in the infiltrated plant and accumulation of the heterologous polypeptide;
• such that approximately 700 mg TurboGFP/kg (tGFP/kg) frozen leaf weight can be obtained in Nicotiana tabacum plants of line PM 132 when using an assay system comprising Agrobacterium strains AGL1 and EHA105, respectively, harboring a gene construct comprising the tGFP gene cloned under the control of the cauliflower mosaic virus 35S promoter and HT-CPMV sequence and the NOS terminator sequence, under the proviso that Agrobacterium strain AGL1 and EHA105, respectively, does not contain a virus expression vector.