My interest in plant biology began during my time as an undergraduate student at Queen’s University in Kingston, Ontario. After taking a specialized plant biology course, I became fascinated with how plants adapted to a variety of stressors and changes in environmental conditions at the molecular level. After completing a summer research work placement with Dr. Sharon Regan, I went on to complete an undergraduate thesis project focusing on the genetic regulation of trichome production in poplar, followed by a Master’s program (also with Dr. Regan) examining the effects of misexpression of an actin-encoding gene on trichome morphogenesis and pollen tube growth in Arabidopsis thaliana.During my time as a Master’s student, I had taken a strong liking to microscopy and decided to pursue this interest further. I began my Ph.D. program with Dr. Robert Mullen at the University of Guelph in the fall of 2014. At this time, Dr. Mullen had just initiated a research program on plant lipid droplets (LDs) in non-seed tissues. Briefly, LDs are ER-derived, spherical organelles that store energy-rich neutral lipids, such as triacylglycerols. Uniquely delineated by just a single phospholipid monolayer and coated with a variety of proteins, LDs have been historically studied in the cells specializing in fat storage (such as seed embryonic cells) and have been thought to be merely inert storage depots. However, all plant cell types, including those that do not specialize in fat storage, produce and contain LDs. This led to the obvious question: what are the functions of LDs in non-seed cell types? Furthermore, given some LD coat proteins are exclusively expressed in seeds, what are the proteins that govern LD biology in cells such as leaves? Thus, the focus of my Ph.D. research was to understand the dynamics of plant LDs in non-seed cell types and to identify and characterize proteins involved in the formation, turnover, and regulation of activity.
Over the course of my Ph.D. program, I helped to characterize the Arabidopsis SEIPIN protein family (which serve as LD biogenetic proteins), the lipid droplet-associated proteins (LDAPs; which are ubiquitously-expressed, stabilizing LD coat proteins), and the LDAP-interacting protein (LDIP; which serves as regulator of LD size and neutral lipid homeostasis in leaves and seeds). Additionally, I also determined that leaf LD formation is linked to the diurnal cycle in Arabidopsis and that LD proliferation is a general response to temperature stress, a process mediated by the LDAPs. Taken together, my research has allowed for the generation of a model of LD biogenesis that involves the SEIPINs, LDAPs, and LDIP and can be applied to design biotechnological strategies for (i) increasing neutral lipid levels in non-seed tissues and (ii) engineering LDs to store lipids of economic value. Continued research from other groups have contributed to the current view that plant LDs are highly dynamic and involved in a number of intracellular processes.
I joined Lacey’s lab in the fall of 2018 as a Mitacs Elevate post-doctoral fellow in association with BioCan Technologies Inc. The objective of my research will be to understand the cell biology of cannabinoid synthesis and trafficking in Cannabis sativa. Cannabinoids, as well as strongly-scented terpenes, are stored in glandular trichome heads in Cannabis floral tissue following the secretion of precursors from underlying disk cells. It is suspected these compounds are secreted by ABC transporters, which are currently the focuses of my research.
Publications
Huang, L., Pyc, M., Alseekh, S., Aarabi, F., McCarty, D., Crecy-Legard, V., Gregory, J., Henry, C., Fernie, A., Mullen, R.T., and Hanson, A.D. (2018). A plastidial pantoate transporter with a potential role in pantothenate synthesis. Biochemical Journal, BCJ20170883. [view abstract]
Pyc, M., Cai, Y., Gidda, S., Yurchenko, O., Park, S., Kretschmar, F, Ischebeck, T., Valerius, O., Braus, G., Chapman, K.D, Dyer, J.M., and Mullen, R.T. (2017). An Arabidopsis LDAP-interacting protein (LDIP) influences lipid droplet size and neutral lipid homeostasis in both leaves and seeds. The Plant Journal, 92(6):1182-1201. [view abstract]
Pyc, M., Cai, Y., Greer, M.S., Yurchenko, O., Chapman, K.D., Dyer, J.M., and Mullen, R.T. (2017). Turning Over a New Leaf in Lipid Droplet Biology. Trends in Plant Science, 22(7): 596-609. [view abstract]
Ying, S., Hill, A.T., Pyc, M., Anderson, E.A., Snedden, W.A., Mullen, R.T., She, Y-M., and Plaxton, W.C. (2017). Regulatory Phosphorylation of Bacterial-type PEP Carboxylase by the Ca2+-Dependent Protein Kinase RcCDPK1 in Developing Castor Oilseeds. Plant Physiology, 174(2): 1012-1027. [view abstract]
Fedosejevs, E. T., Gerdis, S. A., Ying, S., Pyc, M., Anderson, E. M., Snedden, W. A., Mullen, R.T., She, Y.M., and Plaxton, W. C. (2016). The calcium-dependent protein kinase RcCDPK2 phosphorylates sucrose synthase at Ser11 in developing castor oil seeds. Biochemical Journal, 473(20), 3667-3682. [view abstract]
Gidda, S.K., Park, S., Pyc, M., Yurchenko, O., Cai, Y., Wu, P., Andrews, D.W., Chapman, K.D., Dyer, J.M., and Mullen, R.T. (2016). Lipid droplet-associated proteins (LDAPs) are required for the dynamic regulation of neutral lipid compartmentation in plant cells. Plant Physiology, 170: 2052-2071. [view abstract]
Cai, Y., Goodman, J. M., Pyc, M., Mullen, R. T., Dyer, J. M., and Chapman, K. D. (2015). Arabidopsis SEIPIN Proteins Modulate Triacylglycerol Accumulation and Influence Lipid Droplet Proliferation. The Plant Cell, 27(9): 2616-2636. [view abstract]
