Depletion of the NbCORE receptor drastically improves agroinfiltration productivity in older Nicotiana benthamiana plants.
Nicotiana benthamiana is increasingly used for transient gene expression to produce antibodies, vaccines, and other pharmaceutical proteins but transient gene expression is low in fully developed, 6-8wk old plants. This low gene expression is thought to be caused by the perception the cold shock protein (CSP) of Agrobacterium tumefaciens. The CSP receptor is contested because both NbCSPR and NbCORE have been claimed to perceive CSP. Here, we demonstrate that CSP perception is abolished in 6wk-old plants silenced for NbCORE but not NbCSPR. Importantly, older NbCORE-silenced plants support a drastically increased level of GFP fluorescence and protein upon agroinfiltration. The drastic increase in transient protein production in NbCORE depleted plants offers new opportunities for molecular farming, where older plants with larger biomass can now be used for efficient protein expression.