Tobacco leaves and roots differ in the expression of proline metabolism-related genes in the course of drought stress and subsequent recovery.

In plants, members of gene families differ in function and mode of regulation. Fine-tuning of the expression of individual genes helps plants to cope with a variable environment. Genes encoding proline dehydrogenase (PDH), the key enzyme in proline degradation, and the proline biosynthetic enzyme, Δ(1)-pyrroline-5-carboxylate synthetase (P5CS), play an important role in responses to osmotic and drought stresses.

Comparison of hormonal responses to heat, drought and combined stress in tobacco plants with elevated proline content.

In order to test the possibility of improving tolerance to heat and drought (alone and in combination) by elevation of the osmoprotectant proline (Pro) content, stress responses were compared in tobacco plants constitutively over-expressing a gene for the Pro biosynthetic enzyme Δ(2)-pyrroline-5-carboxylate synthetase (P5CSF129A; EC 2.7.2.

The role of cytokinins in responses to water deficit in tobacco plants over-expressing trans-zeatin O-glucosyltransferase gene under 35S or SAG12 promoters.

The impact of water deficit progression on cytokinin (CK), auxin and abscisic acid (ABA) levels was followed in upper, middle and lower leaves and roots of Nicotiana tabacum L. cv. Wisconsin 38 plants [wild type (WT)].