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Plant Physiology 100:820-825 (1992) © 1992 American Society of Plant Biologists Normal Growth of Transgenic Tobacco Plants in the Absence of Cytosolic Pyruvate Kinase 1Department of Biology, Queen's University, Kingston, Ontario, Canada, K7L 3N6, Plant Research Centre, Agriculture Canada, Ottawa, Ontario, Canada, K1A 0C6
The coding sequence of the cytosolic isozyme of potato tuber pyruvate kinase (PK) was attached to the transit peptide of the small subunit of pea ribulose-1,5-bisphosphate carboxylase oxygenase and placed under the control of the cauliflower mosaic virus 35S promoter. This construct was transformed into Nicotiana tabacum. Unexpectedly, two primary transformants were recovered in which PK activity in leaves was greatly reduced. The reduction in PK activity appeared to result from the complete absence of the cytosolic form of the enzyme (PKc). In addition, no PKc could be detected on western blots of leaf extracts. Metabolite analyses indicated that the levels of phosphoenolpyruvate are substantially higher in PKc-deficient leaves than in wild-type leaves, consistent with a block in glycolysis at the step catalyzed by PK. PKc deficiency in the leaves does not appear to adversely affect plant growth. Analysis of progeny indicates that PKc deficiency is a heritable trait. The leaves of PKc-deficient transformants have normal rates of photosynthetic O2 evolution and respiratory O2 consumption, indicating that these plants are using alternative pathways to bypass PK.
2 Present address: Central Institute of Medicinal and Aromatic Plants, P.O. Bag No. 1, Ram Sagar Misra Nagar, Lucknow-226016, India. 3 Present address: MSU/DOE Plant Research Laboratory and Department of Biochemistry, Michigan State University, East Lansing, MI 48824. 4 Present address: Department of Botany, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4. 1 Research was supported by a strategic grant from the Natural Sciences and Engineering Research Council of Canada and the Plant Research Center, Agriculture Canada. Plant Research Centre Contribution No. 1398. This article has been cited by other articles:
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