Phosphomannose Isomerase Gene, Antibiotic, Herbicide Resistance, Hexokinase, Mannopse six Phosphate, Culture Medium, Sole Carbon Source

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Gene Transfer Methods in Plants Gene Transfer Methods in Plants Introduction Target Cells for Transformation Theoretical Routes for Production of Transgenic Plants Vectors of Gene Transfer Vectors based on Ti and Ri Plasmids of Agrobacterium Structure and Function of Ti and Ri Plasmids Selectable Marker Genes in Vectors Used for Gene Transfer T-DNA Transfer Process Vectors based on Ti and Ri Plasmids Virus Vectors Transformation Techniques Using Agrobacterium Prerequisites for Production of Transgenic Plants Explants Used for Transformation Marker Genes for Selection and Scoring of Tranformed Cells/Calli or Shoots Reporter Genes Used as Scoreable Markers and their Enzyme Assays Neomycin Phosphotransferase Gene (nptII) Chloramphenicol Acetyl Transferase Gene (cat)

Home >> Plant Biotechnology and Genomics >> Gene Transfer Methods in Plants >>Phosphomannose Isomerase Gene (pmi)

Phosphomannose Isomerase Gene (pmi).
Although the genes for antibiotic and herbicide resistance as selectable markers for plant transformation have been shown to be completely safe and seem to pose no risk to the farmers or consumers, public concerns have been voiced against these markers, particularly when used in food crops. Therefore, efforts have been made to use systems (e.g., ere-lox; see later), which will remove the selectable marker, after the selection of transformed cells is over. However, to address public concerns, efforts are also being made to phase out the use of antibiotic resistance genes as markers. As a step in this direction, during 2000-2001, a company named Novartis developed and used a selectable marker system that makes use of phosphomannose isomerase gene (pmi)derived from E. coli. The product of this gene, the enzyme phosphomannose isomerase (PMI) converts mannopse-6-phosphate (obtained from mannose due to action of hexokinase) to fructose-6- phosphate, which can be utilized by transformed cultured cells.

The method for the use of this marker system in crop plants involves cells or tissues using any method, followed by placement of these cells in a culture medium, to which mannose is added as a substrate either as a sole carbon source or in combination with sucrose. Mannose has no adverse effect on plant cells, but selection occurs due to its phosphorylation to monnose-6- phosphate by hexokinase. In tissues lacking PMI, mannose-6-phosphate accumulates and the cells stop growing, thus offering selection of transformed cells, which can metabolise monnose-6-phospote due to the presence of gene pmi.

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β-Glucuronidase (GUS)Gene (uidA) Luciferase Gene (lux) Green Fluorescent Protein Gene Phosphomannose Isomerase Gene (pmi) Agrobacterium-Mediated Transformation in Monocots Agroinfection and Gene Transfer Physical Delivery or DNA Mediated Gene Transfer (DMGT) Chemically Stimulated DNA Uptake by Protoplasts Microinjection and Macroinjection Microprojectiles for Gene Transfer Electroporation Method for Gene Transfer Liposome Mediated Gene Transfer Calcium Phosphate Precipitation Method Transformation Using Pollen or Pollen Tube Incubation of Dry Seeds,Embryos,Tissues or Cell in DNA Transformation by Ultrasonication Removal of Selectable Marker Gene from Transgenic Plants Need for Removal of Selectable Marker Gene Genetic Systems Used for Removal of Marker Gene Examples of North American Plant Transformation Facilities Plant Transformation Facilities (PTFs)

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