title: The expression of a recombinant glycolate dehydrogenase polyprotein in potato (Solanum tuberosum) plastids strongly enhances photosynthesis and tuber yield.
abstract: We have increased the productivity and yield of potato (Solanum tuberosum) by developing a novel method to enhance photosynthetic carbon fixation based on expression of a polyprotein (DEFp) comprising all three subunits (D, E and F) of Escherichia coli glycolate dehydrogenase (GlcDH). The engineered polyprotein retained the functionality of the native GlcDH complex when expressed in E. coli and was able to complement mutants deficient for the D, E and F subunits. Transgenic plants accumulated DEFp in the plastids, and the recombinant protein was active in planta, reducing photorespiration and improving CO2 uptake with a significant impact on carbon metabolism. Transgenic lines with the highest DEFp levels and GlcDH activity produced significantly higher levels of glucose (5.8-fold), fructose (3.8-fold), sucrose (1.6-fold) and transitory starch (threefold), resulting in a substantial increase in shoot and leaf biomass. The higher carbohydrate levels produced in potato leaves were utilized by the sink capacity of the tubers, increasing the tuber yield by 2.3-fold. This novel approach therefore has the potential to increase the biomass and yield of diverse crops.
authors.affiliation: Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany.
authors.forename: Greta
authors.initials: G
authors.lastname: Nölke
authors.forename: Marcel
authors.initials: M
authors.lastname: Houdelet
authors.forename: Fritz
authors.initials: F
authors.lastname: Kreuzaler
authors.forename: Christoph
authors.initials: C
authors.lastname: Peterhänsel
authors.forename: Stefan
authors.initials: S
authors.lastname: Schillberg
mesh_terms: D050260:Carbohydrate Metabolism; D004926:Escherichia coli / Q000201:enzymology; D055442:Metabolome; D010088:Oxidoreductases / Q000378:metabolism*; D010641:Phenotype; D010788:Photosynthesis; D018515:Plant Leaves / Q000378:metabolism; D035281:Plant Tubers / Q000254:growth & development* / Q000378:metabolism; D030821:Plants, Genetically Modified; D018087:Plastids / Q000378:metabolism; D020815:Polyproteins / Q000378:metabolism*; D021122:Protein Subunits / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism*; D011198:Solanum tuberosum / Q000235:genetics*
chemical_list: D020815:Polyproteins; D021122:Protein Subunits; D011994:Recombinant Proteins; D010088:Oxidoreductases
keywords: biomass; carbon metabolism; photorespiration; transgenic plants; tuber size