Register      Login
Functional Plant Biology Functional Plant Biology Society
Plant function and evolutionary biology
RESEARCH ARTICLE

Osmotic stress changes carbohydrate partitioning and fructose-2,6-bisphosphate metabolism in barley leaves

Dorthe Villadsen A , Jesper Henrik Rung A and Tom Hamborg Nielsen A B
+ Author Affiliations
- Author Affiliations

A Plant Biochemistry Laboratory, Department of Plant Biology, Royal Veterinary and Agricultural University, 40 Thorvaldsensvej, DK-1871 Frederiksberg C, Denmark.

B Corresponding author. Email: thni@kvl.dk

Functional Plant Biology 32(11) 1033-1043 https://doi.org/10.1071/FP05102
Submitted: 28 April 2005  Accepted: 11 July 2005   Published: 28 October 2005

Abstract

Carbohydrate metabolism was investigated in barley leaves subjected to drought or osmotic stress induced by sorbitol incubation. Both drought and osmotic stress resulted in accumulation of hexoses, depletion of sucrose and starch, and 5–10-fold increase in the level of the regulatory metabolite fructose-2,6-bisphosphate (Fru-2,6-P2). These changes were paralleled by an increased activity ratio of fructose-6-phosphate,2-kinase / fructose-2,6-bisphosphatase (F2KP). The drought-induced changes in carbohydrate content and Fru-2,6-P2 metabolism were reversed upon re-watering. This reveals a reversible mechanism for modification of the F2KP enzyme activity. This suggests that F2KP might be involved in altering carbohydrate metabolism during osmotic stress. However, labelling with [14C]-CO2 showed that sucrose synthesis was not inhibited, despite the increased Fru-2,6-P2 levels, and demonstrated that increased flux into the hexose pools probably derived from sucrose hydrolysis. Similar effects of osmotic stress were observed in leaf sections incubated in the dark, showing that the changes did not result from altered rates of photosynthesis. Metabolism of [14C]-sucrose in the dark also revealed increased flux into hexoses and reduced flux into starch in response to osmotic stress. The activities of a range of enzymes catalysing reactions of carbohydrate metabolism in general showed only a marginal decrease during osmotic stress. Therefore, the observed changes in metabolic flux do not rely on a change in the activity of the analysed enzymes. Fructose-2,6-bisphosphate metabolism responds strongly to drought stress and this response involves modification of the F2KP activity. However, the data also suggests that the sugar accumulation observed during osmotic stress is mainly regulated by another, as yet unidentified mechanism.

Keywords: carbohydrate metabolism, drought, fructose-2,6-bisphosphate, Hordeum vulgare, osmotic stress.


Acknowledgments

This research was supported by The Danish National Research Foundation, Centre for Molecular Plant Physiology and by the PhD student scholarship program at Royal Veterinary and Agricultural University. We are grateful to Andrew Weatherall for critically reading the manuscript.


References


Banzai T, Hanagata N, Dubinsky Z, Karube I (2003) Fructose-2,6-bisphosphate contents were increased in response to salt, water and osmotic stress in leaves of Bruguiera gymnorrhiza by differential changes in the activity of the bifunctional enzyme 6-phosphofructo-2-kinase / fructose-2,6-bisphosphate 2-phosphatase. Plant Molecular Biology 53, 51–59.
Crossref | GoogleScholarGoogle Scholar | PubMed | open url image1

Beutler HO (1984) Monosaccharides and derivatives. In ‘Methods of enzymatic analysis. Volume 6’. (Ed. HU Bergmeyer) pp. 321–327. (Verlag Chemie: Weinheim)

Chaves MM, Maroco JP, Pereira JS (2003) Understanding plant responses to drought — from genes to the whole plant. Functional Plant Biology 30, 239–264.
Crossref | GoogleScholarGoogle Scholar | open url image1

Dancer J, David M, Stitt M (1990) Water stress leads to a change of partitioning in favour of sucrose in heterotrophic cell suspension cultures of Chenopodium rubrum. Plant, Cell & Environment 13, 957–963. open url image1

Dihazi H, Kessler R, Eschrich K (2004) High osmolarity glycerol (HOG) pathway-induced phosphorylation and activation of 6-phosphofructo-2-kinase are essential for glycerol accumulation and yeast cell proliferation under hyperosmotic stress. Journal of Biological Chemistry 279, 23961–23968.
Crossref | GoogleScholarGoogle Scholar | PubMed | open url image1

Draborg H, Villadsen D, Nielsen TH (1999) Cloning, characterization and expression of a bifunctional fructose-6-phosphate,2-kinase / fructose-2,6-bisphosphatase from potato. Plant Molecular Biology 39, 709–720.
Crossref | GoogleScholarGoogle Scholar | PubMed | open url image1

Draborg H, Villadsen D, Nielsen TH (2001) Transgenic Arabidopsis plants with decreased activity of fructose-6-phosphate,2-kinase / fructose-2,6-bisphosphatase have altered carbon partitioning. Plant Physiology 126, 750–758.
Crossref | GoogleScholarGoogle Scholar | PubMed | open url image1

Furumoto T, Teramoto M, Inada N, Ito M, Nishida I, Watanabe A (2001) Phosphorylation of a bifunctional enzyme, 6-phosphfructo-2-kinase / fructose-2,6-bisphosphatase, is regulated physiologically and developmentally in rosette leaves of Arabidopsis thaliana. Plant & Cell Physiology 42, 1044–1048.
Crossref | GoogleScholarGoogle Scholar | PubMed | open url image1

Geigenberger P, Reimholz RR, Geiger M, Merlo L, Canale V, Stitt M (1997) Regulation of sucrose and starch metabolism in potato tubers in response to short-term water deficit. Planta 201, 502–518.
Crossref | GoogleScholarGoogle Scholar | open url image1

Goggin DE, Setter TL (2004) Fructosyltransferase activity and fructan accumulation during development in wheat exposed to terminal drought. Functional Plant Biology 31, 11–21.
Crossref | GoogleScholarGoogle Scholar | open url image1

Hare PD, Cress WA, Staden JV (1998) Dissecting the roles of osmolyte accumulation during stress. Plant, Cell & Environment 21, 535–553.
Crossref | GoogleScholarGoogle Scholar | open url image1

Hatzfeld WD, Dancer J, Stitt M (1990) Fructose-2,6-bisphosphate, metabolites and ‘coarse’ control of pyrophosphate : fructose-6-phosphate phosphotransferase during triose-phosphate cycling in heterotrophic cell-suspension cultures of Chenopodium rubrum. Planta 180, 205–211. open url image1

Hoekstra FA, Golovina EA, Buitink J (2001) Mechanisms of plant dessication tolerance. Trends in Plant Science 6, 431–438.
Crossref | GoogleScholarGoogle Scholar | PubMed | open url image1

Huber JLA, Huber SC, Nielsen TH (1989) Protein phosphorylation as a mechanism for regulation of spinach leaf sucrose-phosphate synthase activity. Archives of Biochemistry and Biophysics 270, 681–690.
Crossref | GoogleScholarGoogle Scholar | PubMed | open url image1

Kerepesi I, Galiba G, Banyai E (1998) Osmotic and salt stresses induced differential alteration in water-soluble carbohydrate content in wheat seedlings. Journal of Agricultural and Food Chemistry 46, 5347–5354.
Crossref | GoogleScholarGoogle Scholar | open url image1

Kulma A, Villadsen D, Campbell DG, Meek SEM, Nielsen TH, MacKintosh C (2004) Phosphorylation and 14-3-3 binding of Arabidopsis 6-phosphofructo-2-kinase / fructose-2,6-bisphosphatase. The Plant Journal 37, 654–667.
Crossref | GoogleScholarGoogle Scholar | PubMed | open url image1

Kunst A, Draeger B, Ziegenhorn J (1984) Monosaccharides and derivatives. In ‘Methods of enzymatic analysis. Volume 6’. (Ed. HU Bergmeyer) pp. 163–172. (Verlag Chemie: Weinheim)

Lopes MS, Nogués S, Araus JL (2004) Nitrogen source and water regime effects on barley photosynthesis and isotope signature. Functional Plant Biology 31, 995–1003.
Crossref | GoogleScholarGoogle Scholar | open url image1

Markham JE, Kruger NJ (2002) Kinetic properties of bifunctional 6-phosphofructo-2-kinase / fructose-2,6-bisphosphatase from spinach leaves. European Journal of Biochemistry 269, 1267–1277.
Crossref | GoogleScholarGoogle Scholar | PubMed | open url image1

Nielsen TH (1992) Differences in fructose-2,6-bisphosphate metabolism between sections of developing barley leaves. Physiologia Plantarum 84, 577–583.
Crossref | GoogleScholarGoogle Scholar | open url image1

Nielsen TH, Veierskov B (1990) Regulation of carbon partitioning in source and sink leaf parts in sweet pepper (Capsicum annuum L.) plants. Plant Physiology 93, 637–641. open url image1

Nielsen TH, Wischmann B (1995) Quantitative aspects of the in vivo regulation of pyrophosphate : fructose-6-phosphate 1-phosphotransferase by fructose-2,6-bisphosphate. Plant Physiology 109, 1033–1038.
PubMed |
open url image1

Nielsen TH, Stitt M (2001) Tobacco transformants with strongly decreased expression of pyrophosphate : fructose-6-phosphate expression in the base of their young growing leaves contain much higher levels of fructose-2,6-bisphophate but no major changes in fluxes. Planta 214, 106–116.
PubMed |
open url image1

Nielsen TH, Skjærbæk HC, Karlsen P (1991) Carbohydrate metabolism during fruit development in sweet pepper (Capsicum annuum) plants. Physiologia Plantarum 82, 311–319.
Crossref | GoogleScholarGoogle Scholar | open url image1

Nielsen TH, Rung JH, Villadsen D (2004) Fructose-2,6-bisphosphate: a traffic signal in plant metabolism. Trends in Plant Science 9, 556–563.
Crossref | GoogleScholarGoogle Scholar | PubMed | open url image1

Quick P, Siegl G, Neuhaus E, Feil R, Stitt M (1989) Short-term water stress leads to a stimulation of sucrose synthesis by activating sucrose-phosphate synthase. Planta 177, 535–546.
Crossref | GoogleScholarGoogle Scholar | open url image1

Reddy AR (1996) Fructose 2,6-bisphosphate-modulated photosynthesis in sorghum leaves grown under low water regimes. Phytochemistry 43, 319–322.
Crossref | GoogleScholarGoogle Scholar | open url image1

Reddy AR (2000) Photosynthesis and fructose 2,6-bisphosphate content in water stressed wheat leaves. Cereal Research Communications 28, 131–137. open url image1

Rung JH, Draborg H, Jørgensen K, Nielsen TH (2004) Carbon partitioning in leaves and tubers of transgenic potato plants with reduced activity of fructose-6-phosphate,2-kinase / fructose-2,6-bisphosphatase. Physiologia Plantarum 121, 204–214.
Crossref | GoogleScholarGoogle Scholar | PubMed | open url image1

Scott P, Lange AJ, Pilkis SJ, Kruger NJ (1995) Carbon metabolism in leaves of transgenic tobacco (Nicotiana tabacum L.) containing elevated fructose 2,6-bisphosphate levels. The Plant Journal 7, 461–469.
Crossref | GoogleScholarGoogle Scholar | PubMed | open url image1

Scott P, Kruger NJ, Lange AJ (2000) Photosynthetic carbon metabolism in leaves of transgenic tobacco (Nicotiana tabacum L.) containing decreased amounts of fructose 2,6-bisphosphate. Planta 211, 864–873.
Crossref | GoogleScholarGoogle Scholar | PubMed | open url image1

Sicher RC, Bunce JA (1987) Effects of light and CO2 on fructose 2,6-bisphosphate levels in barley primary leaves. Plant Physiology and Biochemistry 25, 525–530. open url image1

Sicher RC, Kremer DF, Harris WG (1986) Control of photosynthetic sucrose synthesis in barley primary leaves. Role of fructose 2,6-bisphosphate. Plant Physiology 82, 15–18. open url image1

Sowokinos JR (1976) Pyrophosphorylases in Solanum tuberosum 1. Changes in ADP-glucose and UDP-glucose pyrophosphorylase activities associated with starch biosynthesis during tuberization, maturation, and storage of potatoes. Plant Physiology 57, 63–68. open url image1

Stitt M (1990) Fructose-2,6-bisphosphate as a regulatory molecule in plants. Annual Review of Plant Physiology and Plant Molecular Biology 41, 153–185.
Crossref | GoogleScholarGoogle Scholar | open url image1

Thomas H, James AR (1999) Partitioning of sugars in Lolium perenne (perennial ryegrass) during drought and on rewatering. New Phytologist 142, 295–305.
Crossref | GoogleScholarGoogle Scholar | open url image1

Toroser D, Huber SC (1997) Protein phosphorylation as a mechanism for osmotic-stress activation of sucrose-phosphate synthase in spinach leaves. Plant Physiology 114, 947–955.
Crossref | GoogleScholarGoogle Scholar | PubMed | open url image1

Trevanion SJ, Castleden CK, Foyer CH, Furbank RT, Quick WP, Lunn JE (2004) Regulation of sucrose-phosphate synthase in wheat (Triticum aestivum) leaves. Functional Plant Biology 31, 685–695.
Crossref | GoogleScholarGoogle Scholar | open url image1

Truesdale MR, Toldi O, Scott P (1999) The effect of elevated concentrations of fructose 2,6-bisphosphate on carbon metabolism during deacidification in the crassulacean acid metabolism plant Kalanchoe daigremontiana. Plant Physiology 121, 957–964.
Crossref | GoogleScholarGoogle Scholar | PubMed | open url image1

Van Schaftingen E (1984) d-Fructose 2,6-bisphosphate. In ‘Methods of enzymatic analysis. Volume 6’. (Ed. HU Bergmeyer) pp. 335–341. (Verlag Chemie: Weinheim)

Villadsen D, Nielsen TH (2001) N-terminal truncation affects the kinetics and structure of fructose-6-phosphate 2-kinase / fructose-2,6-bisphosphatase from Arabidopsis thaliana. Biochemical Journal 359, 591–597.
Crossref | GoogleScholarGoogle Scholar | PubMed | open url image1

Villadsen D, Rung JH, Draborg H, Nielsen TH (2000) Structure and heterologous expression of a gene encoding fructose-6-phosphate,2-kinase / fructose-2,6-bisphosphstase from Arabidopsis thaliana. Biochimica et Biophysica Acta 1492, 406–413.
PubMed |
open url image1

Wingler A, Quick WP, Bungard RA, Bailey KJ, Lea PJ, Leagood RC (1999) The role of photorespiration during drought stress: an analysis utilizing barley mutants with reduced activities of photorespiratory enzymes. Plant, Cell & Environment 22, 361–373.
Crossref | GoogleScholarGoogle Scholar | open url image1

Zrenner R, Stitt M (1991) Comparison of the effect of rapidly and gradually developing water-stress on carbohydrate metabolism in spinach leaves. Plant, Cell & Environment 14, 939–946. open url image1