A 24-h photoperiod before gene transfer promotes biomass production but not the yield of influenza hemagglutinin transiently expressed in Nicotiana benthamiana

Abstract

The effects of continuous lighting (CL) before gene transfer on leaf biomass, leaf hemagglutinin (HA) content per biomass, and leaf HA content per plant in Nicotiana benthamiana after gene transfer were investigated in a transient gene expression system. A control photoperiod of 16 h d and an extended photoperiod of 24 h d were compared at two photosynthetic photon flux density (PPFD) levels of 200 and 400 μmol m s. Leaf biomass was greater in the 24 h d photoperiod treatments and 400 μmol m s PPFD treatments. The leaf HA content per biomass was smaller at 24 h d than at 16 h d, indicating that CL before gene transfer had a negative impact on leaf HA accumulation per biomass after gene transfer. There was no significant difference in leaf HA content per biomass between 200 and 400 μmol m s PPFD. As a result, the leaf HA content per plant was significantly greater in the high PPFD treatments but not significantly different between photoperiod treatments. The results indicate that a simple approach of applying CL before gene transfer increases biomass but not the HA yield and is thus not necessarily cost‐effective in the plant‐based recombinant protein production system.