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Heat-soluble proteins extracted from wheat embryos have tightly bound sugars and unusual hydration properties

Published online by Cambridge University Press:  19 September 2008

Christina Walters ,
Jeffrey L. Ried  and
M. K. Walker-Simmons
Christina Walters*
Affiliation:
USDA-ARS, National Seed Storage Laboratory, 1111 S. Mason St. Fort Collins, CO 80521, USA formerly Christina W. Vertucci
Jeffrey L. Ried
Affiliation:
USDA-ARS, 209 Johnson Hall, Washington State University, Pullman, WA 99164-6420, USA
M. K. Walker-Simmons
Affiliation:
USDA-ARS, 209 Johnson Hall, Washington State University, Pullman, WA 99164-6420, USA
*
*Correspondence
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Abstract

Late embryogenesis abundant (LEA) proteins accumulate in developing seeds prior to maturation drying and are presumed to help protect embryos from desiccation stress. The unusual solubility properties of these proteins, such as resistance to heat coagulation, have led to suggestions that they alter the hydration properties of cellular constituents. Hydration characteristics and water potential range at which wheat heat-soluble LEA proteins were expressed have been determined. Levels of heatsoluble proteins decline in germinating seeds but can be induced by dehydration (ψ ≤ −0.5 MPa) in crown meristematic tissue that is desiccation tolerant. The heatsoluble extract from mature wheat embryos contained proteins and sugars at about a 1:1 (w/w) ratio. Only about half of the sugars could be removed by exhaustive dialysis; the rest appeared to be tightly associated with the proteins. The water sorption characteristics of undialysed and dialysed heat-soluble protein/sugar fractions were compared with other water-soluble proteins (bovine serum albumin, lysozyme or gluten) and with sucrose. At relative humidities greater than 50%, the amount of water absorbed by protein-sugar mixes was a function of the sugar content. For the same sugar content, the heat-soluble protein preparation absorbed 2–3 times more water than a lysozyme/sucrose preparation. The rate at which heat-soluble protein fractions dried was also different to desorption rates of lysozyme/sucrose mixes. While lysozyme/sucrose mixtures dried either very rapidly (within 20 min) or very slowly (about 2 months) depending on the sugar content, desorption rates of the heat soluble protein-sugar preparations were intermediate (2–10 days) and modulated by sugar concentration. Based on the presumption that the hydrophilic properties of LEA heat-soluble proteins are important to their function, it is suggested that these proteins function to control drying so that cells stay at critical water potentials for the proper time. In this respect, the heat-soluble LEA proteins do not prevent desiccation, but serve as hydration buffers.

Keywords

desiccation toleranceglassheat-soluble proteinisothermlate embryogenesis abundantLEA proteinsugarsucrosewater binding
Type
Biochemistry and Metabolism
Information
Seed Science Research , Volume 7 , Issue 2 , June 1997 , pp. 125 - 134
Copyright
Copyright © Cambridge University Press 1997

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References

Black, M., Corbineau, F., Grzesik, M., Guy, P. and Côme, D.(1996) Carbohydrate metabolism in the developing and maturing wheat embryo in relation to its desiccation tolerance. Journal of Experimental Botany 47, 161–169.CrossRefGoogle Scholar
Blackman, S.A., Wettlaufer, S.H., Obendorf, R.L. and Leopold, A.C. (1991) Maturation proteins associated with desiccation tolerance in soybean. Plant Physiology, 96, 868–874.CrossRefGoogle ScholarPubMed
Blackman, S.A., Obendorf, R.L. and Leopold, A.C. (1992) Maturation proteins and sugars in desiccation tolerance of developing soybean seeds. Plant Physiology 100, 225–230.CrossRefGoogle ScholarPubMed
Bradford, K.J. and Chandler, P.M. (1992) Expression of “dehydrin-like” proteins in embryos and seedlings of Zizania palustris and Oryza sativa during dehydration. Plant Physiology 99, 488–494.CrossRefGoogle ScholarPubMed
Bull, H.B. (1944) Adsorption of water vapor by proteins. Journal of the American Chemical Society 66 1499–1507.CrossRefGoogle Scholar
Burke, M.J. (1986) The glassy state and survival of anhydrous biological systems. pp 358–363. in Leopold, A.C. (Ed.) Membranes, metabolism and dry organisms. Ithaca, NY, Cornell University Press.Google Scholar
Chandler, P.M. and Robertson, M. (1994) Gene expression regulated by abscisic acid and its relation to stress tolerance. Annual Review of Plant Physiology and Plant Molecular Biology 45, 113–141.CrossRefGoogle Scholar
Chaplin, M.F. and Kennedy, J.F. (1986) Carbohydrate analysis: a practical approach. Oxford and Washington DC, IRL Press.Google Scholar
Close, T.J., Fenton, R.D., Yang, A., Asghar, R., DeMason, D.A., Crone, D.E., Meyer, N.C. and Moonan, F. (1993) Dehydrin: the protein. pp 104–118in Close, T.J. and Bray, E.A. (Eds) Plant responses to cellular dehydration during environmental stress. Rockville, MD, American Society of Plant Physiology.Google Scholar
Crowe, J.H., Hoekstra, F.A. and Crowe, L.M. (1992) Anhydrobiosis. Annual Review of Physiology 54, 570–599.CrossRefGoogle ScholarPubMed
Crowe, J.H., Crowe, L.M., Leslie, S.B. and Fisk, E. (1993) Mechanisms of stabilization of dry biomolecules in anhydrobiotic organisms. pp 11–20in Close, T.J. and Bray, E.A. (Ed.) Plant responses to cellular dehydration during environmental stress., Rockville, MD, American Society of Plant Physiology.Google Scholar
Curry, J. and Walker-Simmons, M.K. (1993) Sequence analysis of wheat cDNAs for abscisic acid-responsive genes expressed in dehydrated wheat seedlings and the cyanobacterium, Anabaena. pp 128–136in Close, T.J. and Bray, E.A. (Ed.) Plant responses to cellular dehydration during environmental stress. Rockville, MD, American Society of Plant Physiology.Google Scholar
Dure, L. III, (1993) Structural motifs in LEA proteins. pp 91–103in Close, T.J. and Bray, E.A. (Eds) Plant responses to cellular dehydration during environmental stress. Rockville, MD, American Society of Plant Physiology.Google Scholar
Farrant, J.M., Pammenter, N.W., Berjak, P., Farnsworth, E.J. and Vertucci, C.W. (1996) Presence of dehydrin-like proteins and levels of abscisic acid in recalcitrant (desiccation sensitive) seeds may be related to habitat. Seed Science Research 4, 175–182.CrossRefGoogle Scholar
Finch-Savage, W.E., Pramanik, S.K. and Bewley, J.D. (1994) The expression of dehydrin proteins in desiccation-sensitive (recalcitrant) seeds of temperate trees. Planta 193, 478–485.CrossRefGoogle Scholar
Jacobsen, J.V. and Shaw, D.C. (1989) Heat-stable proteins and abscisic acid action in barley aleurone cells. Plant Physiology 91, 1520–1526.CrossRefGoogle ScholarPubMed
Johnston, F.B. and Stern, H. (1957) Mass isolation of viable wheat embryos. Nature 179, 160–161.CrossRefGoogle ScholarPubMed
Kermode, A.R. (1995) Regulatory mechanisms in the transition from seed development to germination: Interactions between the embryo and the seed environment. pp 273–331in Kigel, J., and Galili, G. (Eds) Seed development and germination. New York, Marcel Decker Inc.Google Scholar
Koster, K.L. (1991) Glass formation and desiccation tolerance. Plant Physiology 96, 302–304.CrossRefGoogle ScholarPubMed
Kuo, T.M., VanMiddlesworth, J.E and Wolf, W.J. (1988) Content of raffinose oligosaccharides and sucrose in various plant seeds. Journal of Agricultural Food Chemistry 36, 32–36.CrossRefGoogle Scholar
Lane, B.G. (1991) Cellular desiccation and hydration: developmentally regulated proteins, and the maturation and germination of seed embryos. FASEB 5, 2893–2901.CrossRefGoogle ScholarPubMed
Leopold, A.C., Sun, W.Q. and Bernal-Lugo, I. (1994) The glassy state in seeds: analysis and function. Seed Science Research 4, 267–274.CrossRefGoogle Scholar
Leprince, O. and Walters-Vertucci, C. (1995) A calorimetric study of the glass transition behaviours in axes of bean seeds with relevance to storage stability. Plant Physiology 109, 1471–1481.CrossRefGoogle ScholarPubMed
Levitt, J. (1980) Responses of plants to environmental stresses.Vol 2: Water, radiation, salt, and other stresses. New York, London, Academic Press.Google Scholar
McCubbin, W.D., Kay, C.M. and Lane, B.G. (1985) Hydrodynamic and optical properties of the wheat germ Em protein. Canadian Journal of Biochemistry and Cell Biology. 63, 803–811.CrossRefGoogle Scholar
Ried, J.L. and Walker-Simmons, M.K. (1990) Synthesis of abscisic acid-responsive, heat-stable proteins in embryonic axes of dormant wheat grain. Plant Physiology 93, 662–667.CrossRefGoogle ScholarPubMed
Ried, J.L. and Walker Simmons, M.K. (1993) Group 3 late embryogenesis abundant proteins in desiccation tolerant seedlings of wheat (Triticum aestivum L.). Plant Physiology 102, 125–131.CrossRefGoogle ScholarPubMed
Skriver, K. and Mundy, J. (1990) Gene expression in response to abscisic acid and other osmotic stress. Plant Cell 2, 503–512.Google Scholar
Uemura, M., Gilmour, S.J., Thomashow, M.F. and Steponkus, P.L. (1993) Effect of COR proteins on the freeze-induced fusion of liposomes. Plant Physiology 102 suppl, 35.Google Scholar
Vertucci, C.W. and Farrant, J.M. (1995) Acquisition and loss of desiccation tolerance. pp 237–271in Kigel, J. and Galili, G. (Eds) Seed development and germination. New York, Marcel Decker Inc.Google Scholar
Vertucci, C.W. and Leopold, A.C. (1987) The relationship between water binding and desiccation tolerance in tissues. Plant Physiology 85, 232–238.CrossRefGoogle ScholarPubMed
Vertucci, C.W. and Roos, E.E. (1993) Theoretical basis of protocols for seed storage. II. The influence of temperature on optimal moisture levels. Seed Science Research 3, 201–213.CrossRefGoogle Scholar
Williams, R.J. (1994) Methods for determination of glass transitions in seeds. Annals of Botany 74, 3–12.CrossRefGoogle Scholar