Antisense suppression of proline degradation improves tolerance to freezing and salinity in Arabidopsis thaliana

Abstract

Synthesis, degradation, and transport of proline (Pro) are thought to cooperatively control its endogenous levels in higher plants in response to environmental conditions. To evaluate the function of Pro degradation in the regulation of the levels of Pro and to elucidate roles of Pro in stress tolerance, we generated antisense transgenic Arabidopsis plants with an AtProDH cDNA encoding proline dehydrogenase (ProDH), which catalyzes Pro degradation. Several transgenic lines accumulated Pro at higher levels than wild-type plants, providing evidence for a key role of ProDH in Pro degradation in Arabidopsis. These antisense transgenics were more tolerant to freezing and high salinity than wild-type plants, showing a positive correlation between Pro accumulation and stress tolerance in plants.z 1999 Federation of European Biochemical Societies.

Global plant-responding mechanisms to salt stress: physiological and molecular levels and implications in biotechnology

“…The first transgenic plant with accumulated Pro was acquired in 1995 (Kavi et al, 1995). In Arabidopsis, overexpression of P5CS antisense or the insertional mutant of this gene can reduce the salt tolerance of the transgenic plants (Nanjo et al, 1999;Székely et al, 2008). Meanwhile, we may reduce the degradation of the Pro to maintain its concentration, so the key enzyme PDH during degradation is also manipulated.…”

Cold Induction of Arabidopsis CBF Genes Involves Multiple ICE (Inducer of CBF Expression) Promoter Elements and a Cold-Regulatory Circuit That Is Desensitized by Low Temperature

“…Expression of the CBF regulon of target genes then leads to an increase in freezing tolerance Jaglo-Ottosen et al, 1998;Liu et al, 1998;Kasuga et al, 1999). Multiple mechanisms appear to contribute to the enhancement of freezing tolerance, including the synthesis of cryoprotective polypeptides, such as COR15a (Artus et al, 1996;Steponkus et al, 1998), and the accumulation of compatible solutes that have cryoprotective properties, including Suc, raffinose, and Pro (Nanjo et al, 1999;Gilmour et al, 2000;Taji et al, 2002).Currently, little is known about how the CBF genes are up-regulated in response to low temperatures, but important insights are beginning to emerge. It has been established that the promoters of the CBF genes are responsive to low temperatures (Shinwari et al, 1998), and a transcription factor, Inducer of CBF Expression 1 (ICE1) that has a role in CBF expression has recently been identified (Chinnusamy et al., 2003).…”

“…Expression of the CBF regulon of target genes then leads to an increase in freezing tolerance Jaglo-Ottosen et al, 1998;Liu et al, 1998;Kasuga et al, 1999). Multiple mechanisms appear to contribute to the enhancement of freezing tolerance, including the synthesis of cryoprotective polypeptides, such as COR15a (Artus et al, 1996;Steponkus et al, 1998), and the accumulation of compatible solutes that have cryoprotective properties, including Suc, raffinose, and Pro (Nanjo et al, 1999;Gilmour et al, 2000;Taji et al, 2002).…”

Counting the cost of a cold-blooded life: Metabolomics of cold acclimation

“…Arabidopsis (16). The transcriptional upregulation of the RFO pathway by cold treatment (3,15) was also reflected in the increased accumulation of fructose, glucose, galactinol, sucrose, melibiose, and raffinose (1).…”