to investigate the impact of overexpression of atnrt2.1 transgene from arabidopsis on nitrate uptake rate and to understand the regulation of endogenous hats by nitrate and glutamine amino acid (gln) in tobacco plants, wild-type and transgenic (f line) plants grown on soil for 4 weeks were transferred to hydroponic culture in a controlled-environment with a 16/8h l:d photoperiod at 24? c/20...

A chimeric gene consisting of the coding sequence for chloroplastic Fe superoxide dismutase (FeSOD) from Arabidopsis thaliana, coupled to the chloroplast targeting sequence from the pea ribulose-1,5-bisphosphate carboxylase/oxygenase small subunit, was expressed in Nicotiana tabacum cv Petit Havana SR1. Expression of the transgenic FeSOD protected both the plasmalemma and photosystem II against...

Cryopreserved chloroplasts and thylakoids have recently been proven to be suitable for protein import and integration assays. The possibility of recovering intact plant mitochondria after storage would also facilitate a wide range of investigations that are currently underway on the molecular biology of these organelles, e.g. mitochondrial transcription, RNA editing, in organello protein synthe...

An assay to monitor homologous recombination in plant cells has been established by cotransfecting Nicotiana plumbaginifolia protoplasts with different topological forms of plasmids of various deletion mutants of a non-selectable marker gene, the beta-glucuronidase (GUS) gene. Transient GUS enzyme activities were measured by a sensitive assay. In the nuclear DNA of the cotransfected protoplasts...

Secondary walls in vessels and fibers of dicotyledonous plants are mainly composed of cellulose, xylan, and lignin. Although genes involved in biosynthesis of cellulose and lignin have been intensively studied, little is known about genes participating in xylan synthesis. We found that Arabidopsis thaliana fragile fiber8 (fra8) is defective in xylan synthesis. The fra8 mutation caused a dramati...

The proton-pumping ATPase (H+-ATPase) of the plant plasma membrane is encoded by two major gene subfamilies. To characterize individual H+-ATPases, PMA2, an H+-ATPase isoform of tobacco (Nicotiana plumbaginifolia), was expressed in Saccharomyces cerevisiae and found to functionally replace the yeast H+-ATPase if the external pH was kept above 5.0 (A. de Kerchove d'Exaerde, P. Supply, J.P. Dufou...

The cDNA of tomato chloroplastic Cu/Zn-superoxide dismutase was used to construct transgenic tobacco (Nicotiana plumbaginifolia). It was found that the gene expression of Cu/Zn-superoxide dismutase can constitutively be reduced in the transgenic tobacco plants because of double-stranded (dsRNA) expressed in the form of intronspliced hairpin structures and antisense suppression. Furthermore, the...

In several vegetable species a relationship between the metabolism of active oxygen species and breakage of dormancy has been established. However, scarce information is available on the role of oxidative stress in potato tubers. The purpose of this investigation is to study the effect of CAT genetic modification on the dormancy break of potato tubers. A transgenic approach with partial repress...

We have selected 143 independent Nicotiana plumbaginifolia cell lines that survive in the presence of 5-fluoroorotic acid. These lines show several diverse phenotypes. The majority of these cell lines showed reduced levels of UMP synthase. However, one particular phenotype, which represents 14% of the total independent lines (20 cell lines), showed an unexpected, high level of UMP synthase and ...

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