Metabolic engineering of rice leading to biosynthesis of glycinebetaine and tolerance to salt and cold.
Genetically engineered rice (Oryza sativa L.) with the ability to synthesize glycinebetaine was established by introducing the codA gene for choline oxidase from the soil bacterium Arthrobacter globiformis. Levels of glycinebetaine were as high as 1 and 5 micromol per gram fresh weight of leaves in two types of transgenic plant in which choline oxidase was targeted to the chloroplasts (ChlCOD plants) and to the cytosol (CytCOD plants), respectively. Although treatment with 0.15 M NaCl [corrected] inhibited the growth of both wild-type and transgenic plants, the transgenic plants began to grow again at the normal rate after a significantly less time than the wild-type plants after elimination of the salt stress. Inactivation of photosynthesis, used as a measure of cellular damage, indicated that ChlCOD plants were more tolerant than CytCOD plants to photoinhibition under salt stress and low-temperature stress. These results indicated that the subcellular compartmentalization of the biosynthesis of glycinebetaine was a critical element in the efficient enhancement of tolerance to stress in the engineered plants.
Sakamoto
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National Institute for Basic Biology, Myodaiji, Okazaki, Japan.
Alia
Murata
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Murata
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D000064:Acclimatization; D000429:Alcohol Oxidoreductases / Q000235:genetics* / Q000378:metabolism; D001622:Betaine / Q000378:metabolism*; D002736:Chloroplasts / Q000201:enzymology; D003080:Cold Temperature; D003600:Cytosol / Q000201:enzymology; D018014:Gene Transfer Techniques; D005818:Genetic Engineering / Q000379:methods*; D012275:Oryza / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D009994:Osmolar Concentration; D045322:Photosynthetic Reaction Center Complex Proteins / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000502:physiology*; D010957:Plasmids; D011994:Recombinant Proteins / Q000378:metabolism; D015183:Restriction Mapping; D012231:Rhizobium; D014170:Transformation, Genetic
D045322:Photosynthetic Reaction Center Complex Proteins; D011994:Recombinant Proteins; D001622:Betaine; D000429:Alcohol Oxidoreductases; C019888:choline oxidase