• We are sorry, but NCBI web applications do not support your browser and may not function properly. More information
Logo of plntphysLink to Publisher's site
Plant Physiol. Aug 1995; 108(4): 1387–1394.
PMCID: PMC157516

Overexpression of [delta]-Pyrroline-5-Carboxylate Synthetase Increases Proline Production and Confers Osmotolerance in Transgenic Plants.


Proline (Pro) accumulation has been correlated with tolerance to drought and salinity stresses in plants. Therefore, overproduction of Pro in plants may lead to increased tolerance against these abiotic stresses. To test this possibility, we overexpressed in tobacco the mothbean [delta]-pyrroline-5-carboxylate synthetase, a bifunctional enzyme able to catalyze the conversion of glutamate to [delta]-pyrroline-5-carboxylate, which is then reduced to Pro. The transgenic plants produced a high level of the enzyme and synthesized 10- to 18-fold more Pro than control plants. These results suggest that activity of the first enzyme of the pathway is the rate-limiting factor in Pro synthesis. Exogenous supply of nitrogen further enhanced Pro production. The osmotic potentials of leaf sap from transgenic plants were less decreased under water-stress conditions compared to those of control plants. Overproduction of Pro also enhanced root biomass and flower development in transgenic plants under drought-stress conditions. These data demonstrated that Pro acts as an osmoprotectant and that overproduction of Pro results in the increased tolerance to osmotic stress in plants.

Full Text

The Full Text of this article is available as a PDF (2.4M).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.
  • Boggess SF. Contribution of Arginine to Proline Accumulation in Water-stressed Barley Leaves. Plant Physiol. 1976 Dec;58(6):796–797. [PMC free article] [PubMed]
  • Boyer JS. Plant productivity and environment. Science. 1982 Oct 29;218(4571):443–448. [PubMed]
  • Csonka LN, Hanson AD. Prokaryotic osmoregulation: genetics and physiology. Annu Rev Microbiol. 1991;45:569–606. [PubMed]
  • Delauney AJ, Hu CA, Kishor PB, Verma DP. Cloning of ornithine delta-aminotransferase cDNA from Vigna aconitifolia by trans-complementation in Escherichia coli and regulation of proline biosynthesis. J Biol Chem. 1993 Sep 5;268(25):18673–18678. [PubMed]
  • Delauney AJ, Verma DP. A soybean gene encoding delta 1-pyrroline-5-carboxylate reductase was isolated by functional complementation in Escherichia coli and is found to be osmoregulated. Mol Gen Genet. 1990 May;221(3):299–305. [PubMed]
  • Deutch AH, Smith CJ, Rushlow KE, Kretschmer PJ. Escherichia coli delta 1-pyrroline-5-carboxylate reductase: gene sequence, protein overproduction and purification. Nucleic Acids Res. 1982 Dec 11;10(23):7701–7714. [PMC free article] [PubMed]
  • Deutch AH, Rushlow KE, Smith CJ. Analysis of the Escherichia coli proBA locus by DNA and protein sequencing. Nucleic Acids Res. 1984 Aug 10;12(15):6337–6355. [PMC free article] [PubMed]
  • Gurdon JB. Embryonic induction--molecular prospects. Development. 1987 Mar;99(3):285–306. [PubMed]
  • Hu CA, Delauney AJ, Verma DP. A bifunctional enzyme (delta 1-pyrroline-5-carboxylate synthetase) catalyzes the first two steps in proline biosynthesis in plants. Proc Natl Acad Sci U S A. 1992 Oct 1;89(19):9354–9358. [PMC free article] [PubMed]
  • KEMBLE AR, MACPHERSON HT. Liberation of amino acids in perennial rye grass during wilting. Biochem J. 1954 Sep;58(1):46–49. [PMC free article] [PubMed]
  • Larosa PC, Rhodes D, Rhodes JC, Bressan RA, Csonka LN. Elevated Accumulation of Proline in NaCl-Adapted Tobacco Cells Is Not Due to Altered Delta-Pyrroline-5-Carboxylate Reductase. Plant Physiol. 1991 May;96(1):245–250. [PMC free article] [PubMed]
  • Le Rudulier D, Strom AR, Dandekar AM, Smith LT, Valentine RC. Molecular biology of osmoregulation. Science. 1984 Jun 8;224(4653):1064–1068. [PubMed]
  • Paleg LG, Stewart GR, Bradbeer JW. Proline and glycine betaine influence protein solvation. Plant Physiol. 1984 Aug;75(4):974–978. [PMC free article] [PubMed]
  • Schobert B. Is there an osmotic regulatory mechanism in algae and higher plants? J Theor Biol. 1977 Sep 7;68(1):17–26. [PubMed]
  • Skriver K, Mundy J. Gene expression in response to abscisic acid and osmotic stress. Plant Cell. 1990 Jun;2(6):503–512. [PMC free article] [PubMed]
  • Stewart CR. Inhibition of proline oxidation by water stress. Plant Physiol. 1977 May;59(5):930–932. [PMC free article] [PubMed]
  • Szoke A, Miao GH, Hong Z, Verma DP. Subcellular location of delta-pyrroline-5-carboxylate reductase in root/nodule and leaf of soybean. Plant Physiol. 1992 Aug;99(4):1642–1649. [PMC free article] [PubMed]
  • Tarczynski MC, Jensen RG, Bohnert HJ. Stress protection of transgenic tobacco by production of the osmolyte mannitol. Science. 1993 Jan 22;259(5094):508–510. [PubMed]
  • Voetberg GS, Sharp RE. Growth of the Maize Primary Root at Low Water Potentials : III. Role of Increased Proline Deposition in Osmotic Adjustment. Plant Physiol. 1991 Aug;96(4):1125–1130. [PMC free article] [PubMed]

Articles from Plant Physiology are provided here courtesy of American Society of Plant Biologists


Related citations in PubMed

See reviews...See all...

Cited by other articles in PMC

See all...


  • PubMed
    PubMed citations for these articles

Recent Activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...