Tobacco leaves and roots differ in the expression of proline metabolism-related genes in the course of drought stress and subsequent recovery
Abstract
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, Delta(1)- Alpyrroline-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.