Rothamsted Research

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Designing Seeds for Nutrition and Health

Seeds are major components in a wide range of foods and animal feeds, so their composition is an important determinant of nutritional value. We will focus on understanding and optimising the nutritional value of the seeds of two crops, wheat and brassicas, with the aim of enhancing their impact on health and well-being.

This strategic theme will be delivered through three programmes:

  1. Cereal seeds as a source of dietary minerals and fibre. We will determine the mechanisms for the synthesis and feruloylation of wheat cell walls (1, 2) and exploit this information to develop novel types of wheat with enhanced health benefits. Wheat cell walls are a major source of dietary fibre, with bread alone contributing 20% of the daily adult intake in the UK. However, the fibre intake by UK adults falls far short of dietary recommendations, contributing to increasing health problems. Wheat dietary fibre also contains high levels of phenolic acids (notably ferulic acid) which may reduce cardiovascular disease. Collaborations with Institute of Food Research (IFR) and the Universities of Reading and Birmingham are determining the molecular basis for these health benefits using in vivo and model systems. More than 2 billion people worldwide suffer from mineral deficiencies, notably of iron and zinc. We will also determine the genetic variation in content, form, location and bioavailability of these minerals in wheat grain and identify the mechanisms and genes that determine these differences (3). Genetic engineering will also be used to enhance the contents and bioavailabilities of these minerals.
     
  2. Metabolic engineering. We will generate oilseeds (Brassica and Camelina) producing 20 to 30% of long chain polyunsaturated fatty acids (LCPUFA), typical of those found in oily fish i.e. stearidonic acid, EPA and DHA (4). This will be applicable directly as a source of healthy oils for infant and adult human nutrition, where they have been shown to have proven health benefits. They could also be used in aquaculture to enhance the LCPUFA content in farmed fish, which are currently only maintained by feeding them fish-meal, which is not a sustainable practice (5). IFR and the John Innes Centre will also explore the feasibility of this work in dietary intervention.
     
  3. Control of lipid catabolism. We will control lipid catabolism in seed storage which is essential for an oilseed plant becoming established, prior to becoming photoautotrophic. In the latter stages of oilseed maturation, 10 to 20% of seed triacylglycerol is mobilised, leading to a loss of potential yield and relatively little is understood about the control of lipolysis and peroxisomal β-oxidation (6). In addition to storage oil catabolism, the latter pathway also plays a role in the generation of signalling molecules (7). This work will be conducted in the context of protecting the plant's physiology.

References

1. Nemeth, C., Freeman, J., Jones, H. D., Sparks, C., Pellny, T. K., Wilkinson, M.D., Dunwell, J., Andersson, A..A. M., Aman, P., Guillon, F., Saulnier, L., Mitchell, R. A.C. & Shewry, P.R. (2010) Down-regulation of the CSLF6 gene results in decreased (1,3;1,4)-β-D-glucan in endosperm of wheat. Plant Physiology 152, 1209-1218. DOI: 10.1104/pp.109.151712

2. Toole, G. A., Le Gall, G., Colquhoun, I. J., Nemeth, C., Saulnier, L., Lovegrove, A., Pellny, T., Wilkinson, M.D., Freeman, J., Mitchell, R. A. C., Mills, E. N. C. & Shewry P. R. (2010) Temporal and spatial changes in cell wall composition in developing grains of wheat cv. Hereward. Planta 232, 677-689. DOI: 10.1007/s00425-010-1199-5

3. Zhao, F. J., Su, Y. H., Dunham, S. J., Rakszegi, M., Bedo, Z., McGrath, S. P. & Shewry, P. R. (2009) Variation in mineral micronutrient concentrations in grain of wheat lines of diverse origin. Journal of Cereal Science 49, 290-295. DOI: 10.1016/j.jcs.2008.11.007

4. Ruiz-López, N., Haslam, R. P., Venegas-Calerón, M., Larson, T. R., Graham, I. A., Napier, J. A. & Sayanova, O. (2009) The synthesis and accumulation of stearidonic acid in transgenic plants: a novel source of 'heart-healthy' omega-3 fatty acids. Plant Biotechnology Journal 7, 704-716. DOI: 10.1111/j.1467-7652.2009.00436.x

5. Venegas-Calerón, M., Sayanova, O. & Napier, J.A. (2010) An alternative to fish oils: metabolic engineering of oil-seed crops to produce omega-3 long chain polyunsaturated fatty acids. Progress in Lipid Research 49, 108-119. DOI: 10.1016/j.plipres.2009.10.001

6. Nyathi, Y., De Marcos Lousa, C., van Roermund, C. W., Wanders, R. J. A, Baldwin, S. A., Theodoulou, F. L. & Baker, A. (2010) The Arabidopsis peroxisomal ABC transporter, COMATOSE, complements the Saccharomyces cerevisiae pxa1 pxa2Δ double mutant for metabolism of long chain fatty acids and exhibits fatty acyl-CoA stimulated ATPase activity. Journal of Biological Chemistry 285, 29892-29902. DOI: 10.1074/jbc.M110.151225

7. Holman, T., Jones, P. D., Russell, L., Medhurst, A., Talloji, P., Marquez, J., Úbeda-Tomás, S., Schmuths, H., Tung, S-A., Taylor, I., Footitt, S., Bachmair, A., Theodoulou, F. L. & Holdsworth, M. J. (2009) The N-end rule pathway promotes seed germination and establishment through removal of ABA sensitivity