Plant Storage Products (Carbohydrates, Oils and Proteins)


The majority of foods consumed by humans and their domesticated animals as food sources are ultimately obtained from plants, especially seeds. The storage products in seeds are predominately carbohydrates, oils and proteins, which are synthesised and stored in specialised tissues during seed development. Ultimately the storage products ensure successful establishment of the new plant, and the vigour of the young seedling. For example, the reserves are utilised following germination to support early growth of the seedling, allowing it to survive before it commences photosynthesis and autotrophic growth. Some of the storage compounds of seeds play a direct protective role, allowing the seed to withstand water loss during the final stages of its development, and to survive in the dry state for long periods under adverse environmental conditions. Molecular, proteomic and other approaches are elucidating the regulatory networks of genes and encoded proteins that underlie the biochemical and physiological basis of seed maturation, and the accumulation of stored compounds.

Key Concepts:

  • Seed proteins directly provide more than half of the global intake of dietary protein in humans.

  • In seeds, storage products (carbohydrates, oils and proteins) are accumulated during maturation and are utilised following germination to support early growth of the seedling. Likewise, storage products accumulated over winter in tree bark, tubers and perennial weed roots provide nutrients for rapid resumption of growth in the spring.

  • There are regulatory networks of genes and encoded proteins that control the accumulation of stored compounds during seed maturation.

  • Some of the storage products accumulated in seeds and plants are related to their longevity and protect them against environmental stresses.

  • The genetic engineering of the storage products of seeds and plants is directed towards improving their nutritional, stability and food processing properties.

Keywords: carbohydrate; protein; oil; phytin; seeds; nutrition; seed quality; seedling vigour

Figure 1.

Steps in starch biosynthesis in seeds (a) and schematic representation of the levels of organisation within the starch granule (b–e). (a) In step 1 of starch biosynthesis, the enzyme ADPGlcPPase catalyses the formation of ADPglc and inorganic pyrophosphate from glc‐1‐phosphate and ATP. In step 2, starch synthase (SS) adds glucose units from ADPglc to the nonreducing end of a growing α (1→4)‐linked glucan chain by an α (1→4)‐linkage and releases ADP and Pi. In step 3, the starch‐branching enzyme (SBE) cleaves an α (1→4)‐linked glucan chain and forms an α (1→6)‐linkage between the reducing end of the cleaved chain and the C6 of another glucose residue in an α (1→4)‐linked chain, thus creating a branch. Reproduced with permission Srivastava ; Copyright © Elsevier Press. (b–e) Schematic representation of the levels of organisation within the starch granule. Boxes in (c)–(e) represent the area occupied by the structure of the preceding panel. (b) Two branches of an amylopectin molecule, each consisting of α (1→4)‐linked glucan chains (amylose) attached by α (1→6)‐linkage. (c) A cluster within an amylopectin molecule showing the association of adjacent branches. (d) Clusters are arranged to form alternating crystalline and amorphous lamellae. Crystalline lamellae are more closely packed and represent a more ordered arrangement of amylose and amylopectin chains than amorphous lamellae; the two together form the semicrystalline zone. (e) Slice through a starch granule showing alternating zones of semicrystalline and amorphous zones. (b)–(e) Reproduced with permission from Smith AM (1999) Making starch. Current Opinions in Plant Biology2: 223–229. Copyright © Elsevier Press.

Figure 2.

Storage protein deposition in storage parenchyma cells of pea seed. Electron micrograph of a cell from a developing pea cotyledon. Numerous proteins storage vacuoles are visible. Storage protein is being accumulated as electron‐dense deposits at the periphery of the proteins storage vacuoles. At the end of seed development, the proteins storage vacuoles will be completely filled with protein. The nucleus is at the centre, surrounded by large, electron dense, starch grains. Reproduced with permission from Vitale A and Chrispeels MJ (1992) Sorting of proteins to the vacuoles of plant cells. Bioessays14: 151–160. Micrograph by Craig S, CSIRO, Plant Industry.

Figure 3.

Synthesis and processing of seed storage proteins of dicotyledonous seeds (2S albumins, 7S vicilins, and 12S legumins). Signal peptides are shown in solid black; propeptides are shown by hatched boxes and glycosylation sites are shown by inverted symbols. Processing events that take place enroute to the vacuole are shown on the left, those occurring within the vacuole are shown on the right. Lower figure shows the proteolytic cleavage site used by vacuolar endoproteases, in which there is cleavage of the peptide bond on the C‐terminal side of an asparagine (Asn) residue of the protein. The other amino acid is often, but not always, glycine. Reproduced with permission from Srivastava . Copyright © Elsevier.

Figure 4.

Protein bodies in the endosperm of developing rice grains are derived from the endoplasmic reticulum or from the vacuole. The rough endoplasmic reticulum (RER) of developing rice endosperms is composed of two distinct domains, the cisternal‐ER (CER), where the polysomes translate mRNA for a globulin‐like protein (glutelin), and the protein body‐ER (PBER), which contains polysomes translating mRNA for prolamin (oryzenin). The prolamin is sequestered in the ER lumen and directly distends to form a protein body, whereas the globulin passes via the Golgi apparatus to the vacuoles. Storage protein in a mature rice grain is 5% oryzenin and 85% glutelin.

Figure 5.

Simplified scheme for the synthesis of triacylglycerols in plants. Synthesis involves three cell compartments: the cytosol, the plastid and the endoplasmic reticulum, the latter becoming modified to form the oil bodies. Numbered steps require the following enzymes: (1) desaturase; (2) hydroxylase; and (3) elongase. Polyunsaturation and hydroxylation take place on acyl groups incorporated temporarily into phosphatidylcholine (Pc). Mammalian tissues are not able to desaturate oleate to linoleate: hence, this fatty acid, an essential part of the diet, must be obtained from plant sources.

Figure 6.

Seeds of the severe abi3 mutant of Arabidopsis (abi3‐6) as compared to those of the wild‐type plants. The mutant seeds are green, reduced in their storage reserve content and desiccation‐intolerant. Reproduced with permission from Nambara E, Keith K, McCourt P and Naito S (1994) Isolation of an internal deletion mutant of the Arabidopsis thaliana ABI3 gene. Plant and Cell Physiology35: 509–513. Copyright © Oxford University Press.

Figure 7.

Model of some of the regulatory steps that control seed development (including reserve biosynthesis) based on research on the model plant Arabidopsis. The orange line indicates that the maturation programme can be bypassed in various mutants. There are negative mechanisms that repress seed maturation and developmental programmes during seedling development and vegetative growth. ABA, abscisic acid; GA, gibberellic acid; PcG, polycomb group; PCGP, polycomb group protein; PRC2, polycomb repressive complex 2; PKL, PICKLE; HDAC, histone deacetylase; HIS, HIGH‐LEVEL EXPRESSION OF SUGAR‐INDUCIBLE; VAL, VP1/ABI3‐LIKE; LEC, LEAFY COTYLEDON; FUS3, FUSCA3; TAN, TANMEI; AGL 15, AGAMOUS‐like 15; ABI3, ABSCISIC ACID INSENSITIVE3; SP, seed storage protein; WRI, WRINKLED; TAG, Triacylglycerol. Reproduced with permission from North et al. .

Figure 8.

Post‐genomics strategies applied to seeds for dissecting their composition and/or identifying regulatory and metabolic networks during developmental processes such as reserve biosynthesis and deposition. These strategies can be carried out at the level of the transcriptome, proteome, metabolome, ionome and hormonome (hormone and hormone metabolite profiling). Further, the approaches may be ‘untargeted’ or ‘targeted’ (e.g. confined to a specific tissue, developmental stage or organelle). Seed drawings courtesy of Dr Ying Zeng.

Figure 9.

NMR showing distribution of lipid in a western white pine seed shortly after imbibition. Photo courtesy of Feurtado A and Grewal M, Simon Fraser University and Plant Biotechnology Institute, Canada. Reproduced with permission from Kermode . Copyright © Elsevier.



Anekonda TS, Wadsworth TL, Sabin R et al. (2011) Phytic acid as a potential treatment for Alzheimer's pathology: evidence from animal and in vitro models. Journal of Alzheimer's Disease 23: 21–35.

Baud S, Wuilleme S, To A, Rochat C and Lepiniec L (2009) Role of WRINKLED1 in the transcriptional regulation of glycolytic and fatty acid biosynthetic genes in Arabidopsis. Plant Journal 60: 933–947.

Baxter I (2010) Ionomics: the functional genomics of elements. Brief Functional Genomics 9: 149–156.

Beauregard M and Helford MA (2008) Enhancement of essential amino acid contents in crops by genetic engineering and protein design. Plant Biotechnology Journal 4: 561–574.

Bewley JD and Black M (1994) Seeds. Physiology of Development and Germination, 2nd edn. New York: Plenum Press.

Boisson M, Gomord V, Audran C et al. (2001) Arabidopsis glucosidase I mutants reveal a critical role of N‐glycan trimming in seed development. EMBO Journal 20: 1010–1019.

Boothe J, Nykiforuk C, Shen Y et al. (2010) Seed‐based expression systems for plant molecular farming. Plant Biotechnology Journal 8: 588–606.

Bradford K and Bewley JD (2003) Seeds. Biology, Technology, and Role in Agriculture. In: Chrispeels MJ and Sadava DE (eds) Plants, Genes, and Crop Biotechnology, 2nd edn. American Society of Plant Biologists (ASPB) and ASPB Education Foundation, pp. 212–239. Sudbury: Jones and Bartlett Publishers.

Braybrook SA and Harada JJ (2008) LECs go crazy in embryo development. Trends in Plant Science 13: 1360–1385.

Casey R, Domoney C and Ellis THN (1986) Legume storage proteins and their genes. Oxford Surveys in Plant Molecular Cell Biology 3: 1–96.

Chiwocha S, Ambrose SJ, Loewen S et al. (2003) Metabolic profiling of four classes of plant hormones and metabolites by liquid chromatography electrospray tandem mass spectrometry: an analysis of hormonal control of thermodormancy of lettuce (Lactuca sativa) seeds. Plant Journal 35: 405–417 (Technical Advance).

Chiwocha S, Yang J, Ambrose S et al. (2005) The etr1‐2 mutation in Arabidopsis thaliana affects the abscisic acid, auxin, cytokinin and gibberellin metabolic pathways during maintenance of seed dormancy, moist chilling and germination. Plant Journal 42: 35–48.

Crofts AJ, Washida H, Okita TW et al. (2005) The role of mRNA and protein sorting in seed storage protein synthesis, transport, and deposition. Biochemistry and Cell Biology 83: 728–737.

Dickinson CD, Hussein EH and Nielsen NC (1989) Role of posttranslational cleavage in glycinin assembly. Plant Cell 1: 459–469.

Domoney C, Duc G, Ellis THN et al. (2006) Genetic and genomic analysis of legume flowers and seeds. Current Opinion in Plant Biology 9: 133–141.

Fardet A (2010) New hypotheses for the health‐protective mechanims of whole‐grain cereals: what is beyond fibre? Nutrition Research Reviews 23: 65–134.

Finkelstein RR, Gampala SSL and Rock CD (2002) Abscisic acid signaling in seeds and seedlings. Plant Cell 14: S15–S45.

Gutierrez L, Wuytswinkel OV, Castelain M and Bellini C (2007) Combined networks regulating seed maturation. Trends in Plant Science 12: 1360–1385.

Hood EE (2004) Where, oh where has my protein gone? Trends in Biotechnology 22: 53–55.

Jolliffe NA, Craddock CP and Frigerio L (2005) Pathways of protein transport to seed storage vacuoles. Biochemical Society Transactions 33: 1016–1018.

Kawakatsu T and Takaiwa F (2010) Cereal seed storage protein synthesis: fundamental processes for recombinant protein production in cereal grains. Plant Biotechnology Journal 8: 939–953.

Kermode AR (2003) Seed development. Physiology of maturation. In: Thomas B, Murphy D and Murray B (eds) Encyclopedia of Applied Plant Sciences, pp. 1261–1279. UK: Academic Press.

Kermode AR (2005) Role of ABA in seed dormancy. Journal of Plant Growth Regulation 24: 319–344.

Kermode AR and Bewley JD (1999) Synthesis, processing and deposition of seed proteins: the pathway of protein synthesis and deposition in the cell. In: Shewry PR and Casey R (eds) Seed Proteins, pp. 807–841. Dordrecht: Kluwer Academic Publishers.

Kermode AR and Finch‐Savage W (2002) Desiccation sensitivity in orthodox and recalcitrant seeds in relation to development. In: Black M and Pritchard H (eds) Desiccation and Plant Survival, pp. 149–184. Oxford: CAB International.

Ng DW, Chandrasekharan MB and Hall TC (2006) Ordered histone modifications are associated with transcriptional poising and activation of the phaseolin promoter. Plant Cell 18: 119–132.

North H, Baud S, Debeaujon I et al. (2010) Arabidopis seed secrets unravelled after a decade of genetic and omics‐driven research. Plant Journal 61: 971–981.

Parcy F, Valon C, Kohara A, Misera S and Giraudat J (1997) The ABSCISIC ACID‐INSENSITIVE3, FUSCA3, and LEAFY COTYLEDON1 loci act in concert to control multiple aspects of Arabidopsis seed development. Plant Cell 9: 1265–1277.

Perruc E, Kinoshita N and Lopez‐Molina L (2007) The role of chromatin‐remodeling factor PKL in balancing osmotic stress responses during Arabidopsis seed germination. Plant Journal 52: 927–936.

Rasmussen SK, Ingvardsen CR and Torp AM (2010) Mutations in genes controlling the biosynthesis and accumulation of inositol phosphates in seeds. Biochemical Society Transactions 38: 689–694.

Robinson DG, Oliviusson P and Hinz G (2005) Protein sorting to the storage vacuoles of plants: a critical appraisal. Traffic 6: 615–625.

Santos‐Mendoza M, Dubreucq B, Baud S et al. (2008) Deciphering gene regulatory networks that control seed development and maturation in Arabidopsis. Plant Journal 54: 608–620.

Seo M, Jikumaru Y and Kamiya Y (2011) Profiling of hormones and related metabolites in seed dormancy and germination studies. In: Kermode AR (ed.) Seed Dormancy: Methods and Protocols, Methods in Molecular Biology, vol. 773, pp. 99–112. New York: Springer Science+Business Media.

Shewry PR and Halford NG (2002) Cereal seed storage proteins: structures, properties and role in grain utilization. Journal of Experimental Botany 53: 947–958.

Srivastava LM (2001) Plant Growth and Development. San Diego: Academic Press.

Suzuki M and McCarty DR (2008) Functional symmetry of the B3 network controlling seed development. Current Opinions in Plant Biology 11: 548–553.

Tabe LM and Droux M (2002) Limits to sulfur accumulation in transgenic lupin seeds expressing a foreign sulfur‐rich protein. Plant Physiology 128: 1137–1148.

Terskikh VV and Kermode AR (2011) In vivo nuclear magnetic resonance (NMR) metabolite profiling in plant seeds. In: Kermode AR (ed.) Seed Dormancy: Methods and Protocols, Methods in Molecular Biology, vol. 773, pp. 307–318. New York: Springer Science+Business Media.

Terskikh VV, Feurtado JA, Borchardt S et al. (2005) In vivo 13C NMR metabolite profiling: potential for understanding and assessing conifer seed quality. Journal of Experimental Botany 56: 2253–2265.

Terskikh VV, Muller K, Kermode AR and Leubner‐Metzger G (2011) In vivo 1H NMR microimaging during seed imbibition, germination and early growth. Kermode AR (ed.) Seed Dormancy: Methods and Protocols, Methods in Molecular Biology, vol. 773, pp. 319–327. New York: Springer Science+Business Media.

Terskikh VV, Zeng Y, Feurtado JA et al. (2008) Deterioration of western red cedar (Thuja plicata Donn ex D. Don) seeds: Protein oxidation and in vivo NMR monitoring of storage oils. Journal of Experimental Botany 59: 765–777.

Thompson R, Burstin J and Gallardo K (2009) Post‐genomic studies of developmental processes in legume seeds. Plant Physiology 151: 1023–1029.

Ufaz S and Gallili G (2008) Improving the content of essential amino acids in crop plants: goals and opportunities. Plant Physiology 147: 954–961.

Vicente‐Carbajosa J and Carbonero P (2005) Seed maturation: developing an intrusive phase to accomplish a quiescent state. International Journal of Developmental Biology 49: 645–651.

Wallis JG and Browse J (2010) Lipid biochemists salute the genome. Plant Journal 61: 1092–1106.

Wang H, Rogers JC and Jiang L (2011) Plant RMR proteins: unique vacuolar sorting receptors that couple ligand sorting with membrane internalization. FEBS Journal 278: 59–68.

Yamagata H and Tanaka K (1986) The site of synthesis and accumulation of rice storage proteins. Plant and Cell Physiology 27: 135–145.

Zhang H and Ogas J (2009) An epigenetic perspective on developmental regulation of seed genes. Molecular Plant 2: 610–627.

Further Reading

Chrispeels MJ and Sadava DE (2003) Plants, Genes and Crop Biotechnology. American Society of Plant Biologists (ASPB) and ASPB Education Foundation, 2nd edn. Sudbury: Jones Bartlett Publishers.

Dey PM and Dixon RA (eds) (1985) Biochemistry of Storage Carbohydrates in Green Plants. London: Academic Press.

Kermode AR (1990) Regulatory mechanisms involved in the transition from seed development to germination. Critical Reviews in Plant Sciences 9: 155–195.

Kigel J and Galili G (eds) (1995) Seed Development and Germination. New York: Marcel Dekker.

Shewry PR and Casey R (eds) (1999) Seed Proteins. Amsterdam: Kluwer.

Shewry PR and Stobart K (eds) (1993) Seed Storage Compounds. Biosynthesis, Interactions and Manipulation. Oxford: Clarendon Press.

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Kermode, Allison R(Nov 2011) Plant Storage Products (Carbohydrates, Oils and Proteins). In: eLS. John Wiley & Sons Ltd, Chichester. [doi: 10.1002/9780470015902.a0001325.pub2]