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. We compared the expression patterns of three PDH and two putative P5CS genes during drought stress progression and subsequent recovery. Whereas the NtPDH1 gene was affected little by dehydration or rehydration, the NtPDH2 gene responded rapidly to both conditions, and was down-regulated under drought. The CIG1 gene, encoding cytokinin-inducible PDH, exhibited an intermediate transcription pattern. Whereas P5CS B was not affected by the stress conditions, the P5CS A gene was highly up-regulated during drought stress. CIG1 and NtPDH1 transcription was not activated, and P5CS A was only partially reduced in leaves within 24-h after rehydration, a re-watering period sufficient for large physiological changes to occur. The lack of activation of tobacco PDH genes and incomplete reduction of the P5CS A gene in leaves within 24-h of rehydration may reflect the need for the protection of plants to potential subsequent stresses. The data indicate that recovery is a specific physiological process following different patterns in leaves and roots.

• MeSH
• 1-pyrrolin-5-karboxylátdehydrogenasa genetika   metabolismus   MeSH
• časové faktory MeSH
• fyziologický stres genetika   MeSH
• genetická transkripce MeSH
• kořeny rostlin genetika   metabolismus   MeSH
• kyselina abscisová metabolismus   MeSH
• listy rostlin genetika   metabolismus   MeSH
• období sucha MeSH
• osmotický tlak MeSH
• prolin genetika   metabolismus   MeSH
• prolinoxidasa genetika   metabolismus   MeSH
• regulace genové exprese enzymů MeSH
• regulace genové exprese u rostlin MeSH
• rostlinné geny genetika   MeSH
• rostlinné proteiny genetika   metabolismus   MeSH
• tabák genetika   metabolismus   MeSH
• voda fyziologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH