Plants secrete dozens of proteases that shape the extracellular proteome. The biological roles and the substrates of these enzymes is poorly understood. This knowledge is essential to overcome crucial problems in the biotech industry. Protein production in plants by transient expression in Nicotiana benthamiana through agroinfiltration has become the fastest, safest and cheapest way to produce influenza vaccines. However, other (glyco)proteins that are targeted to the apoplast are unstable and degraded by the plant proteolytic machinery. The aim of this project is to unravel the proteolytic machinery of agroinfiltrated Nicotiana benthamiana to increase recombinant glycoprotein production and identify biological roles of secreted proteases in plants. This project is supported by the European Research Council (ERC) with a consolidator grant (ERC-CoG-2013 project 616449 ‘GreenProteases’).