tThe main strategy for resistance to the herbicide glyphosate in plants is the overexpression of an herbicideinsensitive, bacterial 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS). A glyphosate resistancestrategy based on the ability to degrade the herbicide can be useful to reduce glyphosate phytotox-icity to the crops. Here we present the characterization of glyphosate resistance in transgenic alfalfa(Medicago sativa L.) expressing a plant-optimized variant of glycine oxidase (GO) from Bacillus subtilis,evolved in vitro by a protein engineering approach to efficiently degrade glyphosate. Two constructswere used, one with (GOTP+) and one without (GOTP−) the pea rbcS plastid transit peptide. Molecularand biochemical analyses confirmed the stable integration of the transgene and the correct localizationof the plastid-imported GO protein. Transgenic alfalfa plants were tested for glyphosate resistance bothin vitro and in vivo. Two GOTP+lines showed moderate resistance to the herbicide in both conditions.Optimization of expression of this GO variant may allow to attain sufficient field resistance to glyphosateherbicides, thus providing a resistance strategy based on herbicide degradation
Expression of an Evolved Engineered Variant of a Bacterial Glycine Oxidase Leads to Glyphosate Resistance in Alfalfa
NICOLIA, ALESSANDRO;VERONESI, Fabio;ROSELLINI, Daniele
2014
Abstract
tThe main strategy for resistance to the herbicide glyphosate in plants is the overexpression of an herbicideinsensitive, bacterial 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS). A glyphosate resistancestrategy based on the ability to degrade the herbicide can be useful to reduce glyphosate phytotox-icity to the crops. Here we present the characterization of glyphosate resistance in transgenic alfalfa(Medicago sativa L.) expressing a plant-optimized variant of glycine oxidase (GO) from Bacillus subtilis,evolved in vitro by a protein engineering approach to efficiently degrade glyphosate. Two constructswere used, one with (GOTP+) and one without (GOTP−) the pea rbcS plastid transit peptide. Molecularand biochemical analyses confirmed the stable integration of the transgene and the correct localizationof the plastid-imported GO protein. Transgenic alfalfa plants were tested for glyphosate resistance bothin vitro and in vivo. Two GOTP+lines showed moderate resistance to the herbicide in both conditions.Optimization of expression of this GO variant may allow to attain sufficient field resistance to glyphosateherbicides, thus providing a resistance strategy based on herbicide degradationI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.