Peroxidase-induced wilting in transgenic tobacco plants
- Ohio State Univ., Columbus (United States)
- Univ. of Guelph, Ontario (Canada)
Peroxidases are a family of isoenzymes found in all higher plants. However, little is known concerning their role in growth, development or response to stress. Plant peroxidases are heme-containing monomeric glycoproteins that utilize either H{sub 2}O{sub 2} or O{sub 2} to oxidize a wide variety of molecules. To obtain more information on possible in planta functions of peroxidases, the authors have used a cDNA clone for the primary isoenzyme form of peroxidase to synthesize high levels of this enzyme in transgenic plants. They were able to obtain Nicotiana tabacum and N. sylvestris transformed plants with peroxidase activity that is 10-fold higher than in wild-type plants by introducing a chimeric gene composed of the cauliflower mosaic virus 35S promoter and the tobacco anionic peroxidase cDNA. The elevated peroxidase activity was a result of increased levels of two anionic peroxidases in N. tabacum, which apparently differ in post-translational modification. Transformed plants of both species have the unique phenotype of chronic severe wilting through loss of turgor in leaves, which was initiated a the time of flowering. The peroxidase-induced wilting was shown not to be an effect of diminished water uptake through the roots, decreased conductance of water through the xylem, or increased water loss through the leaf surface of stomata. Possible explanations for the loss of turgor, and the significance of these types of experiments in studying isoenzyme families, are discussed.
- DOE Contract Number:
- FG02-89ER14004
- OSTI ID:
- 7303010
- Journal Information:
- Plant Cell; (United States), Vol. 2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
NICOTIANA
BIOLOGICAL STRESS
PEROXIDASES
BIOLOGICAL FUNCTIONS
DNA-CLONING
ENZYME ACTIVITY
PHENOTYPE
POST-TRANSLATION MODIFICATION
CLONING
DNA HYBRIDIZATION
ENZYMES
HYBRIDIZATION
MAGNOLIOPHYTA
MAGNOLIOPSIDA
ORGANIC COMPOUNDS
OXIDOREDUCTASES
PLANTS
PROTEINS
550200* - Biochemistry