A fluorescence-based array screen for transglutaminase substrates.

Transglutaminases (EC 2.3.2.

Negative regulation of nitrate reductase gene expression by glutamine or asparagine accumulating in leaves of sulfur-deprived tobacco.

Tobacco (Nicotiana tabacum L.) plants were subjected to a prolonged period of sulfur-deprivation to characterize molecular and metabolic mechanisms that permit control of primary N-metabolism under these conditions. Prior to the appearance of chlorotic lesions, sulfur-deprived tobacco leaves showed a strong decrease in the sulfate content and changes in foliar enzyme activities, mRNA accumulation and amino-acid pools.

Greenhouse-grown conditionally lethal tobacco plants obtained by expression of plastidic glutamine synthetase antisense RNA may contribute to biological safety.

A cDNA corresponding to plastidic glutamine synthetase (GS-2), an enzyme involved in photorespiration, was expressed in antisense orientation under the control of a leaf-specific soybean ribulose-1,5-bisphosphate carboxylase/oxygenase small subunit gene promotor in transgenic tobacco to yield conditionally lethal plants. Three transgenic tobacco lines with decreased (at most 64%) foliar GS-2 activity were obtained. These plants grew normally when maintained in an atmosphere with a CO(2) partial pressure sufficiently high (300 Pa CO(2)) to suppress photorespiration.

Leaf-specific overexpression of plastidic glutamine synthetase stimulates the growth of transgenic tobacco seedlings.

The impact of increased plastidic glutamine synthetase (GS-2; EC 6.1. 3.

Regulation of nitrate reductase transcript levels by glutamine accumulating in the leaves of a ferredoxin-dependent glutamate synthase-deficient gluS mutant of Arabidopsis thaliana, and by glutamine provided via the roots.

The regulation by glutamine of the leaf transcript level corresponding to the Arabidopsis thaliana (L.) Heynh. nitrate reductase gene nia2 was examined using a novel approach: we took advantage of the ability of a ferredoxin-dependent glutamate synthase-deficient gluS mutant of A.