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Tim George

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Recent publications

Staff picture: Tim George
Ecological Sciences
Tim.George@hutton.ac.uk
+44 (0)844 928 5428 (*)

The James Hutton Institute
Invergowrie
Dundee DD2 5DA
Scotland UK

Current research interests 

Understanding how plants react to and alter their external environment is key to optimising their nutrition and therefore the sustainability of agriculture and natural ecosystems. I am specifically interested in understanding the physiology of and genetic controls on plant responses to P-deficiency and drought. I have specific expertise in understanding how the external environment mitigates plant physiological and genetic responses to a lack of phosphorus in the rhizosphere. In addition, I am interested in how plants interact with the soil chemical, biological and physical environment to impact nutrient cycles, specifically organic P turnover and nitrification. This work will help identify useful traits and cultivars for future agricultural environments which are more nutrient efficient so that agriculture can be managed at less nutrient replete levels reducing its impact on the wider environment.

 

 

Past research 

  • April 2011-present: Rhizosphere Scientist, The James Hutton Institute, UK.
  • 2007-April 2011: Rhizosphere Scientist, SCRI, UK. Holder of Royal Society of Edinburgh Personal Fellowship
  • 2004-2007: Marie Curie International Fellowship. CSIRO Plant Industry, Australia and SCRI, UK.
  • 2001–2004: Post Doctoral Research Fellow. CSIRO Plant Industry, Australia.
  • 1997–2000: PhD Soil Science. Department of Soil Science, University of Reading, UK and ICRAF, Kenya.
  • 1993–1996: BSc Natural Resources (First Class, Honours). Department of Agricultural and Environmental Sciences, University of Newcastle-upon-Tyne, UK.

 

My personal research and that of the group which I manage, has produced a number of research highlights in the last 5 years.

  1. In an attempt to assess the impact of the transgenic plants which exude phytase on the wider environment we demonstrated that these plants have no discernable impact on the microbial community structure of the rhizosphere. Demonstrating that plants which are genetically modified to alter the biochemistry of the rhizosphere to improve the availability of organic P, will not compromise the microbial ecology of these systems.
  2. In a separate stream of work we have observed that while genetic variability in exuded phosphatases between wheat cultivars exists and this is important to plant nutrition under controlled conditions, it plays a limited role in predicting the P acquisition of plants in the soil environment. Similarly we have demonstrated that the genetic component of P-use efficiency in field grown barley is not robust against changes in cultivation treatment. Together this research challenges the use of screening approaches which screen crop populations for traits involved in plant nutrition in single environments and/or under controlled conditions.  
  3. A recent genotypic screening project has demonstrated significant variation in the rooting characteristics within and between species of cultivated potatoes grown in the field. We have further demonstrated that these characteristics are related to the ability of potato to acquire nutrients and water. Moreover, we have established a “high-throughput” controlled environment screen, which is validated against the field data, to establish the rooting characteristic variation in large mapping populations of potato.
  4. A separate screening project has demonstrated significant genotypic variation between barley cultivars to produce BNI (Biological Nitrification Inhibitors) which will be used to identify genes and cultivars to reduce the production of nitrous oxides by barley enterprises. This work has also demonstrated that this trait has a predictable impact on the community structure of ammonia oxidising bacteria and rates of nitrification in the rhizosphere.
  5. Work in the group has identified tens of bacterial and fungal isolates from Cameroonian soils with the ability to solubilise various forms of inorganic and organic phosphate, these have the potential to be used as inocula to improve the sustainability of subsistence agriculture in Cameroon. Some isolates have been demonstrated to have beneficial impacts on inoculated plants grown with metal phosphates and physical effects on mineral forms of phosphate in contact with these organisms. 
  6. Finally, we have demonstrated that root hairs are critical to the ability of cereal crops to yield under P-deficient conditions and that these plants produce root hairs rather than relying on mycorrhizae to tolerate low P soils. In addition, the presence of root hairs is implicit in the development of rhizosheaths in cereals and this trait is related to the ability of plants to cope with combined abiotic stress including drought and P-deficit. We have also demonstrated that the rhizosheath trait is extremely variable and highly heritable, making it a good target for breeding of improved cultivars of cereal crops for future agricultural environments. 

 

In the last five years I have supervised 2 Ph.D., 1 MSc, 1 MRes, 2 Honours and 1 Nuffield student, I have also hosted 8 visiting scientists from 4 different countries.  We have attracted just short of £1m to fund this research and have produced 14 peer reviewed journal articles, 5 book chapters published (or in press) and a further 5 manuscripts are in the final stages of preparation. This work has been presented on 20 occasions at scientific meeting in the last 2 years.   

Bibliography 

Five most highly cited Publications 

  • Richardson, A.E., Simpson, R.J., George, T.S. & Hocking, P.J. (2009)  Plant Mechanisms to optimize access to soil phosphorus.  Crop and Pasture Science 60, 124-143. (44 citations)
  • George T.S.; Richardson A. E.; Hadobas P. A. and Simpson, R.J. (2004) Characterization of transgenic Trifolium subterraneum L. which expresses phyA and releases extracellular phytase: growth and P nutrition in laboratory media and soil. Plant, Cell and Environment 27:1351-1361. (51 citations)
  • George T. S., Richardson A. E. and Simpson R. J. (2005) Behaviour of plant-derived extracellular phytase upon addition to soil. Soil Biology & Biochemistry 37:977-988. (58 citations)
  • George T.S., Simpson R. J. Hadobas P. A. and Richardson, A.E. (2005) Expression of a fungal phytase gene in Nicotiana tabacum improves phosphorus nutrition of plants grown in amended soils. Plant Biotechnology Journal 3:129-140. (68 citations)
  •  George, T.S., Gregory, P.J., Wood, M., Read, D.J. and Buresh, R.J (2002) Phosphatase activity and organic acid concentrations in the rhizosphere of agroforestry species and maize. Soil Biology and Biochemistry 34:1487-1494 (75 citations)

 

Refereed Publications: 

  • Brown LK, George TS, Thompson JA, Wright G, Lyon J, Hubbard SF, White PJ: (2012) What are the implications of variation in root hair length on P-limited yield in barley (Hordeum vulgare L.). Annals of Botany (doi:10.1093/aob/mcs085)
  • Gregory P J and George T S (2012) Feeding nine billion: the challenge to sustainable crop production. Journal of Experimental Botany (doi:10.1093/jxb/err232)
  • Stutter M I, Shand C A, George T S, Blackwell M S A, Bol R, MacKay R L, Richardson A E, Condron L M, Turner B J, Haygarth P M (2012) Recovering Phosphorus from Soil: A Root Solution? Environmental Science and Technology (dx.doi.org/10.1021/es2044745)
  • Subbarao GV, Sahrawat KL, Nakahara K, Ishikawa T, Kishii M, Rao IM, Hash CT, George TS, Rao PS, Nardi P, Bonnett D, Berry W, Suenaga K, Lata JC (2012) Biological Nitrification Inhibition—A Novel Strategy to Regulate Nitrification in Agricultural Systems. Advances in Agronomy 114 (DOI: 10.1016/B978-0-12-394275-3.00001-8)
  • George, T.S., Brown, L.K., Newton, A.C., Hallett, P.D., Sun, B.H., Thomas, W.T.B. & White, P.J. (2011).  Impact of soil tillage on the robustness of the genetic component of variation in phosphorus (P) use efficiency in barley (Hordeum vulgare L.).  Plant & Soil 339, 113-123.
  • Skiba MS, George TS, Baggs EM, Daniell TJ (2011) Plant influence on nitrification. Biochemical Society Transactions 39, 275–278 (doi:10.1042/BST0390275)
  • Newton AC, Flavell AJ, George TS, Leat P, Mullholland B, Ramsay L, Revoredo-Giha C, Russell J, Steffenson BJ, Swanston JS, Thomas WTB, Waugh R, White PJ, Bingham IJ (2011) Crops that feed the world 4. Barley: a resilient crop? Strengths and weaknesses in the context of food security. Food Security 3, 141-178. (doi:10.1007/s12571-011-0126-3)
  • George TS, Frasson AM, Hammond JP, White PJ (2011) Phosphorus nutrition: rhizosphere processes, plant response and adaptations. Phosphorus in Action, eds Bunemann et al. pp 245-271.
  • George, T.S., Richardson, A.E., Sumei, L., Gregory, P.J. & Daniell, T.D. (2009).  Extracellular release of a heterologous phytase from roots of transgenic plants: does manipulation of rhizosphere biochemistry impact microbial community structure?  FEMS Microbiology Ecology 70, 433–445.
  • Neumann, G., George, T.S. & Plassard, C. 2009.  Strategies and methods for studying the rhizosphere—the plant science toolbox.  Plant and Soil 321, 431–456.
  • Richardson, A.E., Simpson, R.J., George, T.S. & Hocking, P.J. 2009.  Plant Mechanisms to optimize access to soil phosphorus.  Crop and Pasture Science 60, 124-143.
  • Subbarao, G.V., Masahiro, K., Nakahara, K., Ishikawa, T., Tomohiro, B., Tsujimoto, H., George, T.S., Berry, W.L, Hash, C.T. & Ito, O. 2009.  Biological Nitrification Inhibition (BNI) – Is there Potential for Genetic Interventions in Triticeae?  Breeding Science 59, 529–545.
  • George, T.S.,Hocking, P.J., Gregory, P.J. & Richardson, A.E. 2008.  Variation of root-associated phosphatase in wheat cultivars explains their ability to utilise organic P substrates in-vitro, but does not effectively predict P-nutrition in a range soils.  Experimental and Environmental Botany 64, 239-249.
  • George TS, Richardson AE (2008) Potential and limitations to improving crops for enhanced phosphorus utilisation. The ecophysiology of plant-phosphorus interactions eds Hammond et al. pp 247-270
  • George, T.S., Simpson, R.J., Hadobas, P.A., Marshall, D.J. & Richardson, A.E. 2007.  Field fertilisation of pasture increases the content and availability of P liable to mineralisation by phosphatase, but does not improve the relative growth of transgenic plants which exude phytase.  Australian Journal of Agricultural Research 58, 47-55.
  • George, T.S.,Richardson, A.E., Gregory, P.J. & Simpson, R.J. 2007.  Differential interaction of phytase proteins (PhyA) from Aspergillus niger and Peniophora lycii with soil particles has implications for mineralisation of phytate in soil.  Soil Biology and Biochemistry 39, 793-803. 
  • George T.S., Quiquampoix, H., Simpson R.J. and Richardson, A.E. (2007). Interactions between phytase and soil constituents: implications for hydrolysis of inositol phosphates. Inositol phosphates in the soil-plant-animal system, 222-242.

  • Richardson AE, George TS, Jakobsen I, Simpson RJ (2007) Plant Utilisation of Inositol Phosphates. Inositol phosphates in the soil-plant-animal system, 242 ,  

  • George, T.S., Turner, B.L., Gregory, P.J. and Richardson, A.E. 2006. Depletion of organic phosphorus from oxisols in relation to phosphatase activities in the rhizosphere. European Journal of Soil Science 57, 47-57.
  • George, T.S., Richardson. A.E., Smith, J.B., Hadobas, P.A. and Simpson, R.J. 2005. Limitations to the potential of transgenic Trifolium subterraneum L. plants that exude phytase, when grown in soils with a range of organic P content. Plant and Soil 278, 263-274.
  • George T.S., Richardson A.E. and Simpson R.J. 2005. Behaviour of plant-derived extracellular phytase upon addition to soil. Soil Biology and Biochemistry 37, 977-988.
  • George T.S., Simpson R.J. Hadobas P.A. and Richardson, A.E. 2005, Expression of a fungal phytase gene in Nicotiana tabacum improves phosphorus nutrition of plants grown in amended soils. Plant Biotechnology Journal 3, 129-140.
  • George T.S., Richardson A.E., Hadobas P.A. and Simpson, R.J. 2004. Characterization of transgenic Trifolium subterraneum L. which expresses phyA and releases extracellular phytase: growth and P nutrition in laboratory media and soil. Plant, Cell and Environment 27, 1351-1361.
  • George, T.S., Gregory, P.J., Wood, M., Read, D.J. and Buresh, R.J. 2002. Phosphatase activity and organic acid concentrations in the rhizosphere of agroforestry species and maize. Soil Biology and Biochemistry 34, 1487-1494.
  • George, T.S., Gregory, P.J., Robinson, J.S., Buresh, R.J. and Jama, B.A. 2002. Utilisation of soil organic P by agroforestry and crop species in the field, western Kenya. Plant and Soil 246, 53-63.
  • George, T.S., Gregory, P.J., Robinson, J.S., and Buresh, R.J. 2002. Changes in phosphorus concentrations and pH in the rhizosphere of some agroforestry and crop species. Plant and Soil 246, 65-73.

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  • Phone: +44 (0)844 928 5428
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  • Invergowrie Dundee DD2 5DA Scotland
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The James Hutton Research Institute is the result of the merger in April 2011 of MLURI and SCRI. This merger formed a new powerhouse for research into food, land use, and climate change.