Plant Molecular Biology

, Volume 13, Issue 5, pp 513–522 | Cite as

Enhancement of the methionine content of seed proteins by the expression of a chimeric gene encoding a methionine-rich protein in transgenic plants

  • Susan B. Altenbach
  • Karen W. Pearson
  • Gabrielle Meeker
  • Lisa C. Staraci
  • Samuel S. M. Sun


We have constructed a chimeric gene encoding a Brazil nut methionine-rich seed protein which contains 18% methionine. This gene has been transferred to tobacco and expressed in the developing seeds. Tobacco seeds are able to process the methionine-rich protein efficiently from a larger precursor polypeptide of 17 kDa to the 9kDa and 3 kDa subunits of the mature protein, a procedure which involves three proteolytic cleavage steps in the Brazil nut seed. The accumulation of the methionine-rich protein in the seeds of tobacco results in a significant increase (30%) in the levels of the methionine in the seed proteins of the transgenic plants. Our data indicate that the introduction of a chimeric gene encoding a methionine-rich seed protein into crop plants, particularly legumes whose seeds are deficient in the essential sulfur-containing amino acids, represents a feasible method for improving the nutritional quality of seed proteins.

Key words

amino acid enhancement Brazil nut methionine-rich protein nutritional quality plant seed proteins 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    Altenbach SB, Pearson K, Leung FW, Sun SSM: Cloning and sequence analysis of a cDNA encoding a Brazil nut protein exceptionally rich in methionine. Plant Mol Biol 8: 239–250 (1987).Google Scholar
  2. 2.
    Antunes AJ, Markakis P: Protein supplementation of navy beans with Brazil nuts. J Agric Food Chem 25: 1096–1098 (1977).PubMedGoogle Scholar
  3. 3.
    Bailey JM, Davidson N: Methyl mercury as a reversible denaturing agent for agarose gel electrophoresis. Anal Biochem 70: 75–85 (1976).PubMedGoogle Scholar
  4. 4.
    Beachy RN, Chen Z-L, Horsch RB, Rogers SG, Hoffman NJ, Fraley RT: Accumulation and assembly of soybean β-conglycinin in seeds of transformed petunia plants. EMBO J 4: 3047–3053 (1985).Google Scholar
  5. 5.
    Bliss FA, Hall TC: Food legumes-compositional and nutritional changes induced by breeding. Cereal Food World 22: 106–113 (1977).Google Scholar
  6. 6.
    Bradford M: A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein dye binding. Anal Biochem 72: 248–254 (1976).CrossRefPubMedGoogle Scholar
  7. 7.
    Bright SWJ, Shewry PR: Improvement of protein quality in cereals. CRC Crit Rev Plant Sci 1: 49–93 (1983).Google Scholar
  8. 8.
    Ditta G, Stanfield S, Corbin D, Helinski DR: Broad host range DNA cloning system for gram-negative bacteria: construction of a gene bank of Rhizobium meliloti. Proc Natn Acad Sci USA 77: 7347–7351 (1980).Google Scholar
  9. 9.
    Ellis JR, Shirsat AH, Hepher A, Yarwood JN, Gatehouse JA, Croy RRD, Boulter D: Tissue-specific expression of a pea legumin gene in seeds of Nicotiana plumbaginifolia. Plant Mol Biol 10: 203–214 (1988).Google Scholar
  10. 10.
    Feinberg AP, Vogelstein B: A technique for radiolabeling DNA restriction endonuclease fragments to high specific activity. Anal Biochem 132: 6–13 (1983).PubMedGoogle Scholar
  11. 11.
    Hoekema A, Hirsch PR, Hooykaas PJJ, Shilperoort RA: A binary plant vector strategy based on separation of vir-and T-region of the Agrobacterium tumefaciens Ti-plasmid. Nature 303: 179–180 (1983).Google Scholar
  12. 12.
    Hoffman LM, Donaldson DD, Bookland R, Rashda K, Herman EM: Synthesis and protein body deposition of maize 15-kd zein in transgenic tobacco seeds. EMBO J 6: 3213–3221 (1987).Google Scholar
  13. 13.
    Hoffman LM, Donaldson DD, Herman EM: A modified storage protein is synthesized, processed, and degraded in the seeds of transgenic plants. Plant Mol Biol 11: 717–729 (1988).Google Scholar
  14. 14.
    Laemmli UK: Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature 227: 680–685 (1970).PubMedGoogle Scholar
  15. 15.
    Mertz ET, Bates LS, Nelson OE: Mutant gene that changes protein composition and increases lysine content of maize endosperm. Science 145: 279–280 (1964).PubMedGoogle Scholar
  16. 16.
    Moore S: On the determination of cystine as cysteic acid. J Biol Chem 238: 235–237 (1963).Google Scholar
  17. 17.
    Murai N, Sutton DW, Murray MG, Slightom JL, Merlo DJ, Reichert NA, Sengupta-Gopalan C, Stock CA, Barker RF, Kemp JD, Hall TC: Phaseolin gene from bean is expressed after transfer to sunflower via tumor-inducing plasmid vectors. Science 222: 476–482 (1983).Google Scholar
  18. 18.
    Nisbet IT, Beilharz MW: Simplified DNA manipulations based on in vitro mutagenesis. Gene Anal Techn 2: 23–29 (1985).CrossRefGoogle Scholar
  19. 19.
    Prosen DE, Simpson RB: Transfer of a ten-member genomic library to plants using Agrobacterium tumefaciens. Bio/Technology 5: 966–971 (1987).CrossRefGoogle Scholar
  20. 20.
    Sengupta-Gopalan C, Reichert NA, Barker RF, Hall TC, Kemp JD: Developmentally regulated expression of the bean β-phaseolin gene in tobacco seed. Proc Natn Acad Sci USA 82: 3320–3324 (1985).Google Scholar
  21. 21.
    Slightom JL, Sun SM, Hall TC: Complete nucleotide sequence of French bean storage protein gene: phaseolin. Proc Natn Acad Sci USA 80: 1897–1901 (1983).Google Scholar
  22. 22.
    Spielmann A, Simpson RB: T-DNA structure in transgenic tobacco plants with multiple independent integration sites. Mol Gen Genet 205: 34–41 (1986).Google Scholar
  23. 23.
    Sturm A, Voelker TA, Herman EM, Chrispeels J: Correct glycosylation, golgi-processing, and targeting to protein bodies of the vacuolar protein phytohemagglutinin in transgenic tobacco. Planta 175: 170–183 (1988).Google Scholar
  24. 24.
    Sun SSM, Altenbach SB, Leung FW: Properties, biosynthesis and processing of a sulfur-rich protein in Brazil nut (Bertholletia excelsa H.B.K.). Eur J Biochem 159: 597–604 (1987).Google Scholar
  25. 25.
    Sun SSM, Leung FW, Tomic JC: Brazil nut (Bertholletia excelsa H.B.K.) proteins: fractionation, composition, and identification of a sulfur-rich protein. J Agric Food Chem 35: 232–235 (1987).Google Scholar
  26. 26.
    Tao S-H, Fox MRS, Fry BE, John ML, Lee YH, Tomic JC, Sun SM: Methionine bioavailability of a sulfur-rich protein from Brazil nut. Fedn Proc 46: 891 (1987).Google Scholar
  27. 27.
    Wallace JC, Galili G, Kawata EE, Cuellar RE, Shotwell MA, Larkins BA: Aggregation of lysine-containing zeins into protein bodies in Xenopus oocytes. Science 240: 662–664 (1988).PubMedGoogle Scholar
  28. 28.
    Zoller MJ, Smith M: Oligonucleotide-directed mutagenesis: a simple method using two oligonucleotide primers and a single-stranded DNA template. DNA 3: 479–488 (1984).PubMedGoogle Scholar

Copyright information

© Kluwer Academic Publishers 1989

Authors and Affiliations

  • Susan B. Altenbach
    • 1
  • Karen W. Pearson
    • 1
  • Gabrielle Meeker
    • 1
  • Lisa C. Staraci
    • 1
  • Samuel S. M. Sun
    • 2
  1. 1.Plant Cell Research Institute, Inc.DublinUSA
  2. 2.Department of Plant Molecular PhysiologyUniversity of HawaiiHonoluluUSA

Personalised recommendations