title: Overexpression of GA20-OXIDASE1 impacts plant height, biomass allocation and saccharification efficiency in maize.
abstract: Increased biomass yield and quality are of great importance for the improvement of feedstock for the biorefinery. For the production of bioethanol, both stem biomass yield and the conversion efficiency of the polysaccharides in the cell wall to fermentable sugars are of relevance. Increasing the endogenous levels of gibberellic acid (GA) by ectopic expression of GA20-OXIDASE1 (GA20-OX1), the rate-limiting step in GA biosynthesis, is known to affect cell division and cell expansion, resulting in larger plants and organs in several plant species. In this study, we examined biomass yield and quality traits of maize plants overexpressing GA20-OX1 (GA20-OX1). GA20-OX1 plants accumulated more vegetative biomass than control plants in greenhouse experiments, but not consistently over two years of field trials. The stems of these plants were longer but also more slender. Investigation of GA20-OX1 biomass quality using biochemical analyses showed the presence of more cellulose, lignin and cell wall residue. Cell wall analysis as well as expression analysis of lignin biosynthetic genes in developing stems revealed that cellulose and lignin were deposited earlier in development. Pretreatment of GA20-OX1 biomass with NaOH resulted in a higher saccharification efficiency per unit of dry weight, in agreement with the higher cellulose content. On the other hand, the cellulose-to-glucose conversion was slower upon HCl or hot-water pretreatment, presumably due to the higher lignin content. This study showed that biomass yield and quality traits can be interconnected, which is important for the development of future breeding strategies to improve lignocellulosic feedstock for bioethanol production.
authors.affiliation: Department of Plant Systems Biology, VIB, Gent, Belgium.|Department of Plant Biotechnology and Bioinformatics, Ghent University, Gent, Belgium.|Plant Sciences Unit - Growth and Development, Institute for Agricultural and Fisheries Research (ILVO), Melle, Belgium.
authors.forename: Wannes
authors.initials: W
authors.lastname: Voorend
authors.affiliation: Department of Plant Systems Biology, VIB, Gent, Belgium.|Department of Plant Biotechnology and Bioinformatics, Ghent University, Gent, Belgium.
authors.forename: Hilde
authors.initials: H
authors.lastname: Nelissen
authors.affiliation: Department of Plant Systems Biology, VIB, Gent, Belgium.|Department of Plant Biotechnology and Bioinformatics, Ghent University, Gent, Belgium.
authors.forename: Ruben
authors.initials: R
authors.lastname: Vanholme
authors.affiliation: Plant Sciences Unit - Crop Husbandry and Environment, Institute for Agricultural and Fisheries Research (ILVO), Merelbeke, Belgium.
authors.forename: Alex
authors.initials: A
authors.lastname: De Vliegher
authors.affiliation: Department of Plant Systems Biology, VIB, Gent, Belgium.|Department of Plant Biotechnology and Bioinformatics, Ghent University, Gent, Belgium.
authors.forename: Frank
authors.initials: F
authors.lastname: Van Breusegem
authors.affiliation: Department of Plant Systems Biology, VIB, Gent, Belgium.|Department of Plant Biotechnology and Bioinformatics, Ghent University, Gent, Belgium.
authors.forename: Wout
authors.initials: W
authors.lastname: Boerjan
authors.affiliation: Plant Sciences Unit - Growth and Development, Institute for Agricultural and Fisheries Research (ILVO), Melle, Belgium.
authors.forename: Isabel
authors.initials: I
authors.lastname: Roldán-Ruiz
authors.affiliation: Plant Sciences Unit - Growth and Development, Institute for Agricultural and Fisheries Research (ILVO), Melle, Belgium.
authors.forename: Hilde
authors.initials: H
authors.lastname: Muylle
authors.affiliation: Department of Plant Systems Biology, VIB, Gent, Belgium.|Department of Plant Biotechnology and Bioinformatics, Ghent University, Gent, Belgium.
authors.forename: Dirk
authors.initials: D
authors.lastname: Inzé
mesh_terms: D017360:Arabidopsis / Q000201:enzymology*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D018533:Biomass; D053898:Biosynthetic Pathways / Q000235:genetics; D050260:Carbohydrate Metabolism; D002473:Cell Wall / Q000378:metabolism; D002482:Cellulose / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D008031:Lignin / Q000096:biosynthesis / Q000378:metabolism; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D018515:Plant Leaves / Q000033:anatomy & histology; D018547:Plant Stems / Q000166:cytology / Q000378:metabolism; D030821:Plants, Genetically Modified; D003313:Zea mays / Q000033:anatomy & histology* / Q000235:genetics* / Q000254:growth & development
chemical_list: D029681:Arabidopsis Proteins; D002482:Cellulose; D008031:Lignin; D006899:Mixed Function Oxygenases; C000606235:gibberellin 20 oxidase 1, Arabidopsis
keywords: bioenergy; crop yield; gibberellic acid; lignocellulose; maize; plant growth