title: Effects of plant density on recombinant hemagglutinin yields in an Agrobacterium-mediated transient gene expression system using Nicotiana benthamiana plants.
abstract: Agrobacterium-mediated transient expression systems enable plants to rapidly produce a wide range of recombinant proteins. To achieve economically feasible upstream production and downstream processing, it is beneficial to obtain high levels of two yield-related quantities of upstream production: recombinant protein content per fresh mass of harvested biomass (g gFM-1) and recombinant protein productivity per unit area-time (g m-2/month). Here, we report that the density of Nicotiana benthamiana plants during upstream production had significant impacts on the yield-related quantities of recombinant hemagglutinin (HA). The two quantities were smaller at a high plant density of 400 plants m-2than at a low plant density of 100 plants m-2. The smaller quantities at the high plant density were attributed to: (i) a lower HA content in young leaves, which usually have high HA accumulation potentials; (ii) a lower biomass allocation to the young leaves; and (iii) a high area-time requirement for plants. Thus, plant density is a key factor for improving upstream production in Agrobacterium-mediated transient expression systems. Biotechnol. Bioeng. 2017;114: 1762-1770. © 2017 Wiley Periodicals, Inc.
authors.affiliation: Department of Biological and Environmental Engineering, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan.
authors.forename: Naomichi
authors.identifier: 0000-0003-4103-6520
authors.initials: N
authors.lastname: Fujiuchi
authors.affiliation: Department of Biological and Environmental Engineering, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Matsuda
authors.affiliation: Owensboro Cancer Research Program, James Graham Brown Cancer Center, University of Louisville School of Medicine, Owensboro, Kentucky.|Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, Kentucky.
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Matoba
authors.affiliation: Department of Biological and Environmental Engineering, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Fujiwara
mesh_terms: D060054:Agrobacterium / Q000235:genetics*; D006388:Hemagglutinins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000254:growth & development* / Q000378:metabolism*; D015202:Protein Engineering / Q000379:methods; D011994:Recombinant Proteins / Q000096:biosynthesis* / Q000235:genetics; D014026:Nicotiana / Q000382:microbiology / Q000502:physiology*
chemical_list: D006388:Hemagglutinins; D011994:Recombinant Proteins
keywords: cultivation conditions; environmental conditions; influenza vaccine; molecular farming; plant-made pharmaceuticals; viral vector