EXPRESSION OF ACTIVE ANTIMICROBIAL PEPTIDES IN Nicotiana benthamiana AS COST-EFFECTIVE BIOREACTORS

As an increasing problem of antibiotic resistant bacterial infections in regards to the used of antimicrobial peptides (AMPs), substitutes have become more desirable. The plants could be used theoretically as cost-effective AMP bioreactors. However, recorded heterologous AMP expression in plants is much less than E. coli expression, often resulting in plant cytotoxicity, even in carriage protein-fused AMPs. This indicates that the previously described heterologous AMPs may have a physical characteristic which impedes the efficiency of plant expression. The research has shown that AMPs of native plants have been slightly less cationic than AMPs common to other taxa by means of a meta-analysis of protein databases. To extend these results to the expression of plants in Nicotiana benthamiana, tobacco plant, this study was conducted to test the transitional expression of 10 different heterologous AMPs, which range from + 7 to -5. A carrier protein for AMP expression was used to produce elastin-like polypeptide (ELP). ELP fusion allows a quick and cost-effective purification of temperature change. All five anionic AMPs were well expressed with this system, two of which were at unusually high levels (375 and 563 μg / gfw). In comparison, antimicrobial activities against Staphylococcus epidermidis were in order of magnitude higher than those usually seen for the AMPs found in E. coli systems (minimum average inhibitor concentration of 0.26μ MIC) and correlated with uncleaved fusion peptides. In short, this research identifies a method for expressing AMP fusions in plants with a high yield, which is purified with a simple procedure for temperature-shifting.