Dr. Michael J. Emes

Dr. Michael J. Emes
University Professor Emeritus and former Dean, College of Biological Science
Department of Molecular and Cellular Biology
Email: 
memes@uoguelph.ca
Phone number: 
58905 / 58852
Office: 
SSC 4448
Lab: 
SSC 4409-10

Having graduated with a degree in Biochemistry from the University of Sheffield (the department in which Krebs delineated the citric acid cycle) my interests in plants really began during my PhD studies. In the same Biochemistry Department, I became interested in the regulation of plant metabolism, where I focused on carbon-nitrogen interactions in roots. These interests led me to a post-doctoral period as a research fellow in the Institute of Plant Physiology, at the University of Bern, Switzerland where I followed the same theme, but in relation to photorespiration in leaves. In 1981, I was fortunate to be appointed to a Faculty position in the Department of Botany at the University of Manchester UK . The next 21 years saw a period of great change as we established the largest unified School of Biological Sciences in the UK, where I became Dean of Research. I moved to Guelph in the Summer of 2002 and served continuously as Dean of the College of Biological Science until August 2015.

Prior to moving to Canada, I served on several grant-awarding committees of the UK Biotechnology and Biological Sciences Research Council (BBSRC) and was the national coordinator of a 5 year programme involving 20 laboratories studying the Regulation of Plant Metabolism. I was also the coordinator for a major EU project studying starch synthesis in wheat, which involved laboratories in five countries. I served as a member of the Boards of Governors for two of the premier UK plant science research institutes, The John Innes Centre and the Scottish Crops Research Institute. In the UK and Canada, I was Associate Editor of the Journal of Experimental Botany from 1994-2011.  Since moving to Canada, I have served as President of the Canadian Council of Deans of Science (CCDS), the Provincial Early Researchers Awards panel, and the ORF-Research Excellence panel.  I retired at the end of 2023 and was appointed University Professor Emeritus by the Senate in 2024.

During my career, I have been fortunate to have advised more than 60 research students and post-doctoral research assistants, and received a regular stream of international visitors with whom we collaborate actively. Many of my students and post-docs have gone on to establish outstanding scientific careers in universities, industry, and commerce, as well as being recognized through the awards of prestigious fellowships.  We have an extensive network of ongoing collaborations, involving laboratories in Australia, France, Germany, Japan, the United Kingdom and the United States as well as within Canada.  I work very closely with Dr. Ian Tetlow, a faculty member in the same department. 

  • PhD -- University of Sheffield
  • Postdoctoral Research Fellow, Institute of Plant Physiology, at the University of Bern, Switzerland

Our research has long been focused on understanding the regulation of starch synthesis in storage issues such as the developing seeds of cereals. Starch is the major determinant of yield in such crops, and has wide application in both the food and non-food industries, yet there remain a huge number of unknowns in what limits the production and structure of this important glucan polymer. There is also an increasing realization that different types of starch provide benefits for human health.  For example, Resistant Starch (RS) reduces the glycemic load in foods and helps maintain insulin sensitivity, reducing the incidence of Type 2 Diabetes (T2D).  Recently, serendipitously, we discovered that manipulating starch synthesis in oilseed species has a remarkable effect, improving yield significantly  (see Liu et al 2016) and has led to a new technology being transferred to canola.

Many of our own studies have emanated from the investigation of amyloplasts and chloroplasts, the organelles in which starch is made in order to elucidate the biochemical mechanisms which regulate starch synthesis., These mechanisms include the role of post-translational modification (protein phosphorylation)  and formation of multi-enzyme complexes. The techniques we use to address these questions include proteomic technologies such as mass spectrometry, bioinformatics, protein isolation and organelle purification, coupled with genetic modification and gene-editing.   Our previous research covered cereals as well as the model organism Arabidopsis thaliana. Genetic manipulation of starch biosynthesis in the latter led us, serendipitously, to an exciting new project aimed at improving oilseed production in crops such as canola which has been strongly supported by funding from the Canola Council of Canada.  In summer 2025 we ran our first successful, confined trial of gene-edited and transgenic plants which showed substantial increases in canola oilseed yield under field conditions.

 

Book Chapters and Reviews:

  • Liping Wang, Michael J. Emes and Ian J. Tetlow (2025) Manipulating Source Leaf Starch Metabolism to Increase Crop Yields.  Getreide, Mehl und Brot 4, 15-20
  • Michael J. Emes, Gregory J. MacNeill and Ian J. Tetlow (2021) Heteromeric Protein Interactions in Starch Synthesis. In “Enzymology of Complex alpha-glucans”, (Felix Nitschke, Editor) Chapter 11, 259-289.  CRC Press.
  • Ian J. Tetlow  and Michael J. Emes (2017) Starch Biosynthesis in the Developing Endosperms of Grasses and Cereals.  Agronomy 7, 81; doi:10.3390/agronomy7040081
  • MacNeill, G.J.,  Mehrpouyan, S., Minow, M.A.A.,  Patterson, J.A., Tetlow, I.J. and Emes, M.J. (2017) Starch as a Source, Starch as a Sink: the Bifunctional Role of Starch in Carbon Allocation.  J. Experimental Botany 68, 4433-53.
  • Patterson, J. A., Emes, M.J. and Tetlow, I.J. (2017) Seed development – starch synthesis.  In “Encyclopedia of Applied Plant Sciences” edited by Thomas, B., Murray B.G. & Murphy, D.  Vol. 1, Waltham, MA: Academic Press, 2017, pp. 570–576. 
  • I. J. Tetlow, F. Liu and M. J. Emes (2015) Protein-protein interactions during starch biosynthesis.  In “Starch.  Metabolism and Structure”, Nakamura, Y., (ed.).  Springer.  pp 291-313. 
  • I.J.Tetlow and M.J.Emes (2014) A review of starch branching enzymes and their role in amylopectin biosynthesis. IUBMB Life 66, 546-558. http://dx.doi.org/10.1002/iub.1297
  • Michael J. Emes and Ian J. Tetlow (2012) The role of heteromeric protein complexes in starch synthesis.  In Starch: origins, structure and metabolism, SEB Publishing (I.J.Tetlow Editor) Vol 5, pp 255-278.
  • I. J. Tetlow, F. Liu, A. Makhmoudova and M.J. Emes (2011) Biochemical, Genetic and Molecular Insights on Starch Biosynthesis in Cereals: A Means to Quality Improvement.  In “Wheat.  Science Dynamics: Challenges and Opportunities”, Eds R. N. Chibaar and J. Dexter.  Agrobios (International).  pp 509 – 525.
  • I. J. Tetlow and M. J. Emes (2011) Plant Systems.  Starch Biosynthesis in Higher Plants:  The Starch Granule.  In: Murray Moo-Young (ed.), Comprehensive Biotechnology, Second Edition, Vol 4, pp 37-45.  Elsevier.
  • I. J. Tetlow and M. J. Emes (2011) Plant Systems.  Starch Biosynthesis in Higher Plants:  The Enzymes of Starch Synthesis.  In: Murray Moo-Young(ed.), Comprehensive Biotechnology, Second Edition, Vol 4, pp 47-65.  Elsevier.

Research Papers:

  • Liping Wang, You Wang, Regina Feil, Gregory J. MacNeill, John E. Lunn, Ian J. Tetlow and Michael J. Emes (2025) Plastidial starch phosphorylase regulates maltodextrin turnover during starch granule initiation in Arabidopsis leaves. Plant Physiology, 198  doi.org/10.1093/plphys/kiaf216

Starch phospohorylase is an enigmatic enzyme of plant carbohydrate metabolism.  This paper demonstrates its crucial role in controlling turnover of maltooligosaccharides within chloroplasts.

  • Liping Wang, You Wang, Amina Makhmoudova, Felix Nitschke, Ian J. Tetlow and Michael J. Emes (2022) CRISPR–Cas9-mediated editing of starch branching enzymes results in altered starch structure in Brassica napus.  Plant Physiology 188: 1866–1886. doi.org/10.1093/plphys/kiab535

This study used gene-editing to target six genes of starch branching enzyme in canola and describes the effects this has on distribution of carbon resources within the plant, producing a significant effect on stem thickness.

  • Sahar Mehrpouyan, Usha Menon, Ian J. Tetlow and Michael J. Emes (2021) Protein phosphorylation regulates maize endosperm starch synthase IIa activity and proteinprotein interactions. The Plant Journal 105, 1098-1112.  doi: 10.1111/tpj.15094

This study demonstrates the effects of protein phosphorylation on starch synthase IIa (SSIIa), and is shown to have multiple effects, modulating the enzyme’s catalytic activity and the balance between high molecular weight and low molecular weight complexes, and monomers.

  • You Wang, Liping Wang, Barry J. Micallef, Ian J. Tetlow, Robert T. Mullen, Regina Feil, John E. Lunn, and Michael J. Emes (2020) AKINβ1, a subunit of SnRK1, regulates organic acid metabolism and acts as a global modulator of genes involved in carbon, lipid, and nitrogen metabolism. Journal of Experimental Botany 71, 1010-1018. doi:10.1093/jxb/erz460
  •  
  • Jenelle A. Patterson, Ian J. Tetlow and Michael J. Emes (2018) Bioinformatic and in vitro Analyses of Arabidopsis Starch Synthase 2 Reveal Post-translational Regulatory Mechanisms.  Front. Plant Sci. 9:1338. doi: 10.3389/fpls.2018.01338
  • Liu, F., Zhao, Q., Mano, N., Ahmed, Z., Nitschke, F., Cai, Y., Chapman, K.D., Steup, M., Tetlow, I.J., and Emes, M.J. (2016) Modification of starch metabolism in transgenic Arabidopsis thaliana increases plant biomass and triples oilseed production. Plant Biotechnology Journal.  14, 976-985. doi:10.1111/pbi.12453. 

This paper demonstrated significant, unexpected effects of modifying starch metabolism on flowering and the production of oilseeds.  Work is underway to transfer this technology into other oilseeds such as canola.

  • Boyer, L., Roussel, X., Courseaux, A., Ndjindji, O.M., Lancelon-Pin, C., Putaux, J-L., Tetlow, I.,   Emes, M.J., Pontoire, B., D’Hulst, C., and Wattebled, F. (2016) Expression of E. coli glycogen branching enzyme in an Arabidopsis mutant devoid of endogenous starch branching enzymes induces the synthesis of starch-like polyglucans.  Plant Cell and Environment 39, 1432-1447.  doi: 10.1111/pce.12702

Working with our French collaborators, this work demonstrated that a high molecular weight, glucan polymer can still be made when substituting a bacterial enzyme for the endogenous plant enzymes, although the structure of the polymer formed is quite different from starch. 

  • Sarah A. Dainty, S.A., Klingel, S.L., Pilkey, S.E., McDonald, E., McKeown, B., Emes, M.J. and Duncan, A.M. (2016)  Resistant starch bagels reduce fasting and postprandial insulin in adults at risk for type 2 diabetes. J. Nutr. 146, 2252-2259.

Transferring our understanding of starch biosynthesis to studies of human health, enabled production of baked food products which, when used in a randomised study, were shown to have long term health benefits for the reduction of Type 2 Diabetes.

  • Z. Ahmed, I. J. Tetlow, D. E. Falk, Q. Liu and M. J. Emes (2016) Resistant starch content is related to granule size in barley.  Cereal Chemistry 93, 618-630.
  • Z. Ahmed, A. Regina, M. K. Morell, I .J. Tetlow and M. J. Emes (2015) Protein–protein interactions among enzymes of starch biosynthesis in high-amylose barley genotypes reveal differential roles of heteromeric enzyme complexes in the synthesis of A and B granules). Plant Science, 233, 95-106.

High amylose starches are of importance as sources of resistant starch with concomitant health benefits for Type2 Diabetes and colorectal cancer.  This paper demonstrates the presence of different protein complexes in the synthesis of such starches and that these are differentially distributed between different granule types in barley.

  • CroftsN., Abe N., Oitome, N.F., Matsushima, R., Hayashi, M., Tetlow, I.J., Emes, M.J., Nakamura, Y., and Fujita, N. (2015) Amylopectin biosynthetic enzymes from developing rice seed form enzymatically active protein complexes. J. Exp. Botany.

This paper, with our collaborators in Japan, shows that heteromeric protein complexes of starch biosynthetic enzymes are widely found in cereals and also describes new complexes, not previously observed.

  • Luo, J., Ahmed, R., Kosar-Hashemi, B., Larroque, O., Butardo Jr., V.M., Tanner, G.J., Colgrave, M.L., Upadhyaya, N.M., Tetlow, I.J., Emes, M.J., Millar, A., Jobling, S.A., Morell, M.K. and Li, Z. (2015) The different effects of starch synthase IIa mutations or variation on endosperm amylose content of barley, wheat and rice are determined by the distribution of starch synthase I and starch branching enzyme IIb between the starch granule and amyloplast stroma.  Theor. Appl. Genet. 

This paper with our Australian collaborators reinforces the centrality of SSIIa in the formation of multi-enzyme complexes which influence starch structure by affecting interactions with other key enzymes and their partitioning between soluble stroma and starch granules.

  • F. Zhua, E. Bertoft, Y. Wang, M. Emes, I. Tetlow, and K Seetharaman (2015).  Structure of Arabidopsis leaf starch is markedly altered following nocturnal degradation.  Carbohydrate Polymers 117, 1002-1013
  • A. Makhmoudova, D. Williams, D. Brewer, S. Massey, J. Patterson, A. Silva, K. A. Vassall, F. Liu, S. Subedi, G. Harauz, K.W. M. Siu, I. J. Tetlow and M. J. Emes (2014) Identification of Multiple Phosphorylation Sites on Maize Endosperm Starch Branching Enzyme IIb, a Key Enzyme in Amylopectin Biosynthesis. J. Biol. Chem. 289, 9233-46.

This paper is the first to identify the sites of protein phosphorylation on any enzyme of starch biosynthesis and the characterization of two protein kinases involved.

  • R. M. Subasinghe, F. Liu, U. C. Polack, E. A. Lee, M. J. Emes and I. J. Tetlow (2014) Multimeric states of starch phosphorylase determine protein-protein interactions with starch biosynthetic enzymes in amyloplasts.  Plant Physiology and Biochemistry 83, 168-179.
  • Cisek, R., D. Tokarz, S. Krouglov, M. Steup, M. J. Emes, I. J. Tetlow and V. Barzda (2014). Second Harmonic Generation Mediated by Aligned Water in Starch Granules. The Journal of Physical Chemistry B., 118, 14785-14794.  DOI:10.1021/jp508751s. Link
  • MacNeil, S., Rebry, R.,Tetlow, I.J., M. J. Emes, M.J., McKeown, B. and Graham, T.E.  (2013) Resistant Starch Intake at Breakfast Affects Postprandial Responses in Type 2 Diabetics, and Enhances Insulin Secretion Following a Second Meal.Applied Physiology, Nutrition and Metabolism, 38, 1187-1195. 

This paper demonstrates the health benefits of including resistant starch in baked products in a human health trial, reducing blood glucose levels and enhancing insulin secretion.

  • F. Liu, N. Romanova, E.A. Lee, R. Ahmed, E. Gilbert, M. Evans, M. K. Morell, M. J. Emes, and Ian J. Tetlow­ (2012)  Glucan affinity of starch synthase IIa determines binding of starch synthase I and starch branching enzyme IIb to starch granules Biochemical Journal, 448, 373-387.

This paper highlights the centrality of heteromeric protein complexes to the formation of organised glucan clusters in normal starch.  Here we defined a model for the interactions between 3 enzymes, demonstrating that starch synthase IIa forms the core of a protein-complex to which the other two enzymes are recruited.  Using a novel maize mutant, developed over several years of back-crossing, we showed that a single point mutation in starch synthase IIa prevents it from binding to the starch granule.  As a consequence, the other two enzymes with which it forms a functional protein-complex are also not able to bind to starch, and do not become incorporated into granules.   

  • F. Liu, Z. Ahmed, E. A. Lee, E. Weber, Q. Liu, R. Ahmed, M. K. Morell, M. J. Emes and I. J. Tetlow (2012) Allelic variants of the amylose extender mutation of maize demonstrate phenotypic variation in starch structure resulting from modified protein-protein interactions J. Exp. Bot. 63, 1167-1183.

This paper investigated a genetic variant of a starch branching enzyme IIb mutant in which an inactive enzyme is expressed, and was compared with the effects of a null mutation of the same gene.  As a result, different heteromeric enzyme complexes are formed in the two mutants in vivo, leading to marked alterations in the size of starch granules and the amylose content.  This is critical to an understanding of how variation in protein complexes, rather than just loss of an enzyme activity, influences phenotype. 

  • F. Liu, A. Makhmoudova, E.A. Lee,R. Wait, M.J. Emes and I.J. Tetlow (2009) The amylose extender mutant of maize conditions novel protein-protein interactions between starch biosynthetic enzymes in amyloplasts. J. Exp. Bot 60, 4423-4440

This paper was the first to demonstrate that in a high amylose mutant of maize, lacking branching enzyme IIb, novel stromal protein complexes are formed between starch biosynthetic enzymes.  These complexes contribute to the altered starch phenotype and, as a consequence, become incorporated into starch granules.  Significantly, this paper combined a genetic approach with powerful biochemical and molecular assays which many groups from around the world have visited our lab to learn.   The discovery that the formation of soluble, multi-enzyme complexes in the amyloplast stroma is reflected in the granule composition provides an additional tool to look for genetic variation in the process of starch biosynthesis.

  • I.J. Tetlow, K.G. Beisel, S. Cameron, A. Makhmoudova, F. Liu, N.S. Bresolin, R. Wait,  M.K. Morell, and M. J. Emes (2008) Analysis of Protein Complexes in Wheat Amyloplasts Reveals Functional Interactions among Starch Biosynthetic Enzymes. Plant Physiology 146, 1878-1891: and
  • T.A. Hennen-Bierwagen, F. Liu, R.S. Marsh, S. Kim, Q. Gan, I.J. Tetlow,    M.J. Emes, M.G. James, and A.M. Myers (2008) Multiple Starch Biosynthetic Enzymes from Developing Zea mays Endosperm Associate in Multisubunit Complexes. Plant Physiology 146, 1892-1908

These papers showed for the first time that soluble starch synthases and starch branching enzymes form functional protein complexes in the stroma of amyloplasts. The association of SSI, SSII and SBEII isoforms was shown to be phosphorylation-dependent and has led to much of our recent work on the discovery of the protein kinases involved. These two papers were published back-to-back, and established that the novel regulatory mechanisms discovered in wheat are common within different species of cereal endosperm. Each has been cited about 100 times.

  • I.J. Tetlow, R. Wait, Z. Lu, R. Akkasaeng, C.G. Bowsher, S. Esposito, B. Kosar- Hashemi, M.K. Morell and M.J. Emes (2004) Protein Phosphorylation in Amyloplasts Regulates Starch Branching Enzyme Activity and Protein-Protein Interactions. The Plant Cell: 16, 694-708.

This was the first publication to demonstrate that the pathway of starch synthesis in plants is regulated by protein phosphorylation and that this process can catalyse the formation of multi-enzyme complexes involved in the biosynthesis of starch.

My primary aim in teaching has always been to engage students in the process of discovery and not merely to be a conduit for information. Throughout my career, I have taught at all levels across the undergraduate curriculum as well as having supervised over 25 graduate students. My approach is to encourage students to ask questions and form hypotheses, and not accept everything as 'given' - this, after all, is the basis of the scientific method. At present I teach a first-year course on “Communicating Science” which involves students from across the disciplines, examining methods of communication and the way that language, image, and metaphor can be used to convey a set of ideas, as well as influence decision-making and public policy.

Postdoctoral Research Associate:

  • Dr. Liping Wang

Research Assistant:

  • Dr. Amina Makhmoudova