A new transient expression system for large-scale production of recombinant proteins in plants based on air-brushing an Agrobacterium suspension

Plant transient expression using virus-based vectors is advantageous when high level of gene expression is desired within a short time. In this study, a new system, named "air-brush," has been developed to facilitate a scale-up production of recombinant proteins in plants. GFP was expressed successfully in Nicotiana benthamiana (Nb) plants by air-brushing an Agrobacterium suspension that contained the TMV-based vector p35S-30B-GFP. Key factors influencing the gene expression were optimized, including the Agrobacterium cell density, seedling age, and the growth temperature of plant materials. In addition, the pharmaceutical protein human acidic fibroblast growth factor (ha FGF) was also expressed in Nb plants by the air-brush system. The results demonstrated that using this system is highly advantageous; it is convenient, quick, easily scaled-up, and has a higher expression efficiency than leaf infiltration.