Dr. Ian Tetlow

My early interest in biology grew during my time at high school in Manchester, England, and also made me realize the importance of applied aspects of the biological sciences. My undergraduate degree was in Plant Science in the Faculty of Agriculture at the University of Newcastle-upon-Tyne (England). During my third (final) year at Newcastle I became interested in carbon metabolism in plants (through a combination of undergraduate project work and interesting biochemistry lectures). I pursued my interest in plant carbon metabolism during my Ph.D. studies at University College of North Wales (Bangor), studying the physiological and biochemical aspects of plants infected by biotrophic fungal pathogens under the supervision of Dr. John F. Farrar. I moved back to my native city of Manchester to do post-doctoral work with Dr. Michael Emes, studying starch synthesis in plants, an area of research that I have continued with to this day. At Manchester, I developed methods for isolating the fragile organelles (amyloplasts) responsible for starch synthesis in storage tissues such as cereal endosperms and tubers. I also worked on characterizing plastidial metabolite transporters using liposome-based systems, in collaboration with Dr. Malcolm Jones (University of Manchester). Following post-doctoral studies, I was awarded a Leverhulme Special Research Fellowship, and studied the role of protein phosphorylation in the regulation of starch biosynthesis; at this stage, no role for this mode of regulation had been demonstrated for this pathway. In 2002 I moved to the University of Guelph (Department of Molecular and Cellular Biology).

• B.Sc. University of Newcastle-upon-Tyne
• Ph.D. University College of North Wales (Bangor)

An underlying aim throughout my research career has been to understand how plant metabolism is regulated; and in particular, how carbohydrate metabolism in plastids is regulated. One of the unique aspects of plant cell biology is the compartmentalization of certain metabolic pathways within specialized sub-cellular organelles termed plastids. The origin of plastids is thought to be traced back in time to the ingestion of a photosynthetic cyanobacterial cell by an ancient plastid-less protist, and its eventual transformation into a plastid. Many of the world's most important agricultural products (e.g. starches and oils) are made inside plastids, and the central theme of my research interests has been the study of these important organelles. The major research topics currently being pursued in my laboratory are summarized below.

Regulation of Starch Biosynthesis in Higher Plants

Broadly, this involves examining the control mechanisms underpinning starch biosynthesis in leaf chloroplasts (which make starch during the daytime, and degrade it at night) of the model plant Arabidopsis thaliana, and non-photosynthetic amyloplasts of cereal endosperms such as maize, wheat, barley and rice which make storage starches. More specifically, we are interested in the biochemical control mechanisms governing the many enzymes and enzyme classes which make up the core pathway of starch biosynthesis. This involves investigating the role of protein-protein interactions and protein phosphorylation in coordinating the proteins involved in starch synthesis and degradation within the plastid to produce the highly ordered and complex structure of the starch granule.

Addressing these fundamental scientific questions has potentially important applied benefits, enabling us to make more rational attempts at yield improvement in crops, and design starch structures which are suited to particular end-users, e.g. starches for the food industry with improved human health benefits, or starches for the non-food sector (e.g. paints and coatings). Consequently, this research has led to many collaborations with scientists in academia and in the food and non-food industries around the globe, as evidenced in my publication record.

Related projects also include work on human glycogen storage diseases in collaboration with Dr. Berge Minassian (Hospital for Sick Children, University of Toronto), and understanding factors underpinning starch quality in wheat with Dr. Amy Lin (University of Idaho, USA).

The various projects related to understanding starch metabolism are part of a close, long-standing collaboration with Dr. Michael Emes (Dean of CBS, and faculty member of MCB) and Dr. Matthew Morell (International Rice Research Institute, Philippines). My research on plant starch metabolism is currently funded by OMAFRA, NSERC, and Genome Canada.

Books and Book Chapters

1. Butler, V.M., Tetlow I.J. (2023). Starch synthesis in plants (Chapter 1), In: Starch in Food: Structure, Function and Applications (3^rd Edition) Editor Lars Nilsson. Elsevier (in press).

2. Butler VM, Tetlow IJ. (2022). The biosynthesis of starch in tuberous crop plants. Chapter 5 (Book 1). In: Underground starchy crops of South American origin: production, processing, utilization and economic perspectives. Editors: Marney Pascoli Cereda (UNESP - Brazil), Olivier Vilpoux (UFMS – Brazil) and Maria Teresa Clerici (UNICAMP – Brazil). Elsevier. (in press)

3. Emes MJ, MacNeill GJ, Tetlow IJ. Heteromeric Protein Interactions in Starch Synthesis (Chapter 11). In Enzymology of Complex Alpha-Glucans (Nitschke, F. (Ed.)). CRC-Press, Taylor & Francis Group. Boca Raton. (2021). ISBN: 978-1-138-50520-9 (hbk) ISBN: 978-0-367-76305-3 (pbk) ISBN: 978-1-315-14644-7 (ebk)

4. Tetlow, I.J. and Bertoft, E. (2020). A Review of Starch Biosynthesis in Relation to the Building Block-Backbone Model. International Journal of Molecular Sciences 21(19), 7011. doi:10.3390/ijms21197011

5. Tetlow, I.J. (2018). Starch Biosynthesis in Crop Plants. Editorial for Agronomy Special Edition. Agronomy 8 (issue 6), 1-4 (published May 25th 2018; Agronomy 2018, 8, 81; doi:10.3390/agronomy8060081

6. Goren, A., Ashlock, D., and Tetlow, I.J. (2018). Starch Formation Inside Plastids of Higher Plants. Protoplasma 255, 1855-1876. https://doi.org/10.1007/s00709-018-1259-4

7. MacNeill, G., 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. Journal of Experimental Botany 68, 4433-4453. doi:10.1093/jxb/erx291

8. Tetlow, I.J., and Emes, M.J. (2017). Starch biosynthesis in the developing endosperms of grasses and cereals. Agronomy 7, 81 (1-43). doi:10.3390/agronomy7040081

9. Patterson, J. A., Emes, M. J., and Tetlow, I. J. (2017). Seed Development: Starch Synthesis. Thomas, Murray & Murphy (eds.). Encyclopedia of Applied Plant Sciences, Second Edition. Oxford: Elsevier. 570-576. http://dx.doi.org/10.1016/B978-0-12-394807-6.00207-0

Research Publications (past six years)

1. Harris, P.J., Burrell, M.M., Emes, M.J., Tetlow, I.J. (2023). Effects of post anthesis high temperature stress on carbon partitioning and starch biosynthesis in a spring wheat (Triticum aestivum L.) adapted to moderate growth temperatures. Plant and Cell Physiology 64 (7), 729-745. https://doi.org/10.1093/pcp/pcad030

2. Wang L, Wang Y, Makhmoudova A, Nitschke F, Tetlow IJ, Emes MJ. (2022). CRISPR-Cas9 mediated genome editing of STARCH BRANCHING ENZYMEs in Brassica napus generates a range of mutants with altered starch granule properties. Plant Physiology 188, 1866-1886. doi.org/10.1093/plphys/kiab535

3. Mehrpooyan, S., Menon, U., Tetlow, I.J., and Emes, M.J. (2021). Protein Phosphorylation Regulates Maize Endosperm Starch Synthase IIa Activity and Protein-Protein Interactions. The Plant Journal 105, 1098-1112. doi: 10.1111/tpj.15094

4.You Wang, Barry J. Micallef, Ian J. Tetlow, Robert Mullen, Regina Feil, John E. Lunn, Michael J. Emes. (2020). AKINβ1, a regulatory subunit of SnRK1, regulates organic acid metabolism and acts as a global regulator of genes involved in carbon, lipid and nitrogen metabolism. Journal of Experimental Botany 71 (3), 1010-1028.

5. Butardo, V.M., Luo, J., Li, Z., Gidley, M.J., Tetlow, I.J., Bird, A.J., Fitzgerald, M. Jobling, S., and Rahman, S. (2020). Functional genomic validation of the roles of soluble starch synthase IIa in japonica rice endosperm. Frontiers in Genetics 11, 289. doi: 10.3389/fgene.2020.00289

6. Patterson, J.A., Tetlow, I.J., and Emes, M.J. (2018). Bioinformatic and in vitro analyses of Arabidopsis starch synthase 2 reveal post-translational regulatory mechanisms. Frontiers in Plant Science 9, article 1338. https://doi.org/10.3389/fpls.2018.01338

7. Goldstein, A., Annor, G., Vamadevan, V., Tetlow, I.J., Kirkensgaard, J.J.K., Mortensen, K., Blennow, A., Hebelstrup, K. H., Bertoft, E. (2017). The influence of diurnal photosynthetic activity on the morphology, structure, and thermal properties of normal and waxy barley starch. International Journal of Biological Macromolecules 98, 188-200. dx.doi.org/10.1016/j.ijbiomac.2017.01.118

• BOT2100 Life Strategies of Plants
• BIOT*6700 Communication in Science and Business
• BIOT*6800 Biotechnology Research Project

Graduate Students
Victoria Butler (PhD)

Myah Crosby (MSc)

Daniel Maloney (MSc)*

Rachel Hindle (MSc)

Research Assistants

Dr. Hanan Shaaban

Post-docs

Dr. Liping Wang *