Degrees

• BS, Biochemistry, University of Sussex, UK, 1991
• PhD, Plant Biology, Kings College London, UK, 1997

Research Interests

The endosperm constitutes the major seed storage tissue in cereals and aside from its role in supporting seed germination and early growth, it is vital as a food source in humans and livestock, as well as having many industrial applications. Research in my laboratory focuses on understanding endosperm hardening during maturation and its relationship to protein quality in maize. Maize is an incomplete protein source since its storage proteins are deficient in the essential amino acids, lysine and tryptophan. Maize mutants such as opaque2 reduce storage protein accumulation and their seeds can be used as a complete protein source. However, these mutants have soft, chalky kernels conferring undesirable storage and processing traits. Quality Protein Maize was developed by selecting for genetic modifiers that restore the desirable hard endosperm texture in opaque2 whilst maintaining its high levels of lysine and tryptophan. My research seeks to determine the nature and mode of action of these modifier genes in order to simplify the further development and utilization of maize with improved protein quality. Also by characterizing a series of opaque endosperm mutants, we will generate a complete understanding of the process of endosperm hardening during kernel maturation.

Major Research Activities

• Investigating the nature, mode of action and potential applications of opaque2 modifiers using transcriptional and proteomic profiling
• Identification of genes involved in vitreous endosperm formation by cloning transposon tagged, opaque endosperm mutants
• Characterizing the role of the Floury 1 protein in zein protein body organization

Selected Publications

• Guo, X , Ronhovde, K, Yuan, L, Yao, B, Soundararajan, M, Elthon, T, Zhang, C and Holding, D (2012) Pyrophosphate dependent fructose-6-phosphate 1-phosphotransferase induction and attenuation of Hsp gene expression during endosperm modification in Quality Protein Maize, Plant Physiology, In press.
   
• Holding, D.R., and Messing, J. (2012) Evolution, structure and function of prolamin storage proteins. Invited chapter in: Seed Genomics, Wiley-Blackwell Publishing, Editor, Becraft, P. In press.
   
• Holding, D.R., Hunter, B.G., Klingler, J.P., Wu, S., Guo, X., Gibbon, B.C., Wu, R., Schulze, J., Jung, R., and Larkins, B.A. (2011) Characterization of opaque2 modifier QTLs and candidate genes in recombinant inbred lines derived from the K0326Y Quality Protein Maize inbred. Theoretical and Applied Genetics 122, 783-794.
   
• Reyes, F.C., Chung, T., Holding, D., Jung, R., Vierstra, R., and Otegui, M.S. (2011) Delivery of Prolamins to the Protein Storage Vacuole in Maize Aleurone Cells, The Plant Cell 23, 769-784.
   
• Holding, D.R., Meeley, R.B., Hazebroek, J., Selinger, D, Jung, R. and Larkins, B.A. (2010) Identification and characterization of the maize arogenate dehydrogenase gene family, Journal of Experimental Botany 61: 3663-3673
   
• Wu, R., Holding, D.R., and Messing, J. (2010) Gamma zeins are essential for endosperm modification in Quality Protein Maize. Proceedings of the National Academy of Sciences, USA. 107: 12,810-12,815
   
• Holding, D.R. and Larkins, B. A. (2009) Zein storage proteins, Chapter V: Molecular Biology and Physical Studies, in Molecular Genetic Approaches to Maize Improvement, (A.L. Kriz and B.A. Larkins eds.) pp 269-286. Springer-Verlag Publishers, Heidelberg, Germany.
   
• Holding, D.R., Hunter, B.G., Chung, T., Gibbon, B.C., Ford, C.F., Bharti, A.K., Messing, J., Hamaker, B.R. and Larkins, B.A. (2008) Genetic Analysis of opaque2 Modifier Loci in Quality Protein Maize. Theoretical and applied genetics 117: 157-170.
   
• Holding, D.R. and Larkins, B.A. (2008) Genetic Modification of Seed Storage Proteins. in "Advances in Plant Biochemistry and Molecular Biology" (Lewis, N.G., Ed.-in-chief) Vol. 1, Bioengineering and Molecular Biology of Plant Pathways (Bohnert, H.J. and Nguyen, H.T, eds.), pp. 107-133. Elsevier Publishers, Oxford, UK.
   
• Holding, D.R, Otegui, M.S., Li, B., Meeley, R.B.,  Hunter, B.G., Jung. R. and Larkins, B.A. (2007) The maize Floury1 gene encodes a novel ER protein involved in zein protein-body formation. Plant Cell 19:2569-2582.
   
• Settles, M.,  Holding, D., Tan, B.C. Latshaw, S., Susuki, M, O'Brien, B., Fajardo, D., Wroclwaska, E., Lai, J., Hunter, C., Avigne, W., Peacock, S., Baier, J., Lonon, D., Messing, J., Hannah, L.C., Koch, K., Becraft, P., Larkins, B., and McCarty, D. (2007) Maize Sequence Indexed Knockouts using the UniformMu Transposon Tagging Population. (2007) BMC Genomics, 8:116.
   
• Holding, D.R. and Larkins, B.A. (2006) The development and importance of zein protein bodies in maize endosperm. Maydica 51 (2): 243-254.
   
• Lopez-Valenzuela, J.A., Gibbon, B.C., Holding, D.R., and Larkins, B.A. (2004) Cytoskeletal proteins are coordinately increased in maize genotypes with high levels of eEF1A. Plant Physiology 135: 1784-1797.
   
• Holding, D.R. and Springer, P.S. (2002) The VASCULAR PREPATTERN enhancer trap marks early vascular development in Arabidopsis. Genesis 33 (4): 155-159 2002.
   
• Holding, D.R. and Springer, P.S. (2002) The Arabidopsis gene PROLIFERA is expressed at all stages of reproductive development and is required for cytokinesis. Planta, 214 373-382.
   
• Springer, P.S., Holding. D.R., Groover, A., Yordan, C. and Martienssen, R.A. (2000) The essential Mcm7 protein PROLIFERA is localized to the nucleus of dividing cells during the G1 phase and is required maternally for early Arabidopsis development. Development 127, 1815-1822.
  
  
• Holding, D.R., Springer, P.S. and Coomber, S.A. (2000) The chloroplast and leaf developmental mutant, pale cress, exhibits light-conditional severity and symptoms characteristic of its ABA deficiency. Annals of Botany. 86, 953-962.
   
• Holding, D.R., McKenzie, R.J. and Coomber, S.A. (1994) Genetic and Structural analysis of five mutants with abnormal root morphology generated by the seed transformation method. Annals of Botany 74, 193-204.