Susan Murch

Professor

Biochemistry and Molecular Biology, Chemistry
Other Titles: Coordinator, Biochemistry and Molecular Biology Graduate Program; Canada Research Chair, Natural Products Chemistry
Office: FIP 350
Phone: 250.807.9566
Email: susan.murch@ubc.ca

Graduate student supervisor



Research Summary

Plant chemistry and biotechnology; the identification, quantification, and metabolism of plant secondary metabolites, the impact of these phytochemicals on human health, and the development of technologies for mass-production of specific plant chemicals as medicines, natural health products, food additives, and functional foods.

Courses & Teaching

Plant biochemistry; bioanalytical chemistry; analytical chemistry.

Websites

PlantSMART

Degrees

PhD, University of Guelph
BSc, University of Guelph
MSc, University of Guelph

Research Interests & Projects

 

Chemistry of Natural Non-Protein Amino Acids

BMAA Chemical Structure

The human diet is made up almost entirely of plants or animals that consumed plants. Plant chemistry affects human health in several ways as they are the source of vitamins, nutrients and antioxidants that are essential to good health. Plants are also the source of more than 900 natural non-protein amino acids that protect plant tissues from environmental stress, insect or animal feeding, and may be toxic to humans.

β-N-methylamino-L-alanine (BMAA) is a naturally-occurring non-protein amino acid that was originally discovered in cycad seeds and is produced by cyanobacteria that live in symbiosis with plants or are free living in fresh water and marine environments worldwide. BMAA accumulates in natural food webs from cyanobacteria to plants to animals to people resulting in varying levels of exposure.

Our research involves developing and comparing analytical methods to accurately quantify BMAA in food, environmental and medicinal samples using a triple quad mass spectrometer. Recent projects include the analysis of this potential neurotoxin in natural health food products and in Canadian lakes including Lake Winnipeg. However, there are still have many questions about BMAA and other natural non-protein amino acids. Why do cyanobacteria produce BMAA and do they produce it in response to different environmental conditions? How does BMAA affect human and animal health? Is it possible to measure BMAA in water using a portable device?

These are some of the key questions in BMAA research that the PlantSMART lab is working in collaboration of many researchers from around the world to try to answer.


Chemical Regulation of Plant Signalling and Behaviour

Melatonin

Plants have the ability to sense their environment and respond to changes through production of chemical signals. These changes can be rapid, such as the closing of mimosa or longer term, for example allowing some plants to flourish in a dramatically changed climate.

PlantSMART research is investigating how plants interact with the world through the production of chemical signals such as the human neurotransmitters melatonin (N-acetyl-5-methoxytryptamine) and serotonin (5-hydroxytryptamine).

In human brains, melatonin and serotonin are neurotransmitters involved in circadian rhythms, sleep cycles, digestion and neurological health but recently our lab and others have shown that melatonin and serotonin are also important plant growth regulators with roles in plant defense, growth patterns and reproduction but there is much remaining to be discovered.

Where are these compounds? What are the metabolic mechanisms? How can they be harnessed to solve environmental problems? What effect does their presence in plants have on human health?

These questions are the source of much debate and underlie many of the projects in the PlantSMART lab.


Chemistry of Plant Responses to Light

SpectrumPlants depend on light as a source of energy in order to perform photosynthesis. This process has been replicated in in artificial environments, such as greenhouses, a method known as electro-horticulture. While electro-horticulture has been well-established since the 1880’s, it is constantly being updated with new technology – such as lighting systems.

The most recent advancement is the transition from fluorescent to light emitting diode (LED) bulbs that is occurring across all sectors. However, a change in bulb will cause a change in emission spectrum by varying the wavelengths available for the plants to absorb. The compounds that absorb light in plants are called photoreceptors and different classes are associated with different physiological processes; each with corresponding plant growth regulating hormones. This suggests that the activation of specific photoreceptors through specific wavelengths (colours) of light can be used to manipulate plant growth.

Our research tests this by measuring the concentration of phytohormones with major roles in plant growth such as melatonin (N-acetyl-5-methoxytryptamine), serotonin (5-hydroxytryptamine), auxins and hormones produced in response to stress.


Chemistry of Cannabis and Other Medicinal Plants

It has been estimated that upwards of >30,000 different chemical compounds, referred to as metabolites, can exist in a single plant. All of these metabolites have the potential to invoke a pharmacological response in the human body. PlantSMART research focuses on the implementing advanced statistical models and multivariate statistics to understand the variances in metabolites across different plant conditions. For example, until recently cannabis breeding and selection has lacked rigorous scientific research and development practices. Breeders focused on visual and organoleptic cues to estimate the quality of new strains, which has led to chemically identical or very closely related materials is being sold under several different names by different producers. We have focused on evaluating the impacts of breeding and selection on cannabis metabolites using targeted and untargeted metabolomics.


Plant Chemistry for Food Security

Breadfruit (Artocarpus altilis) is a staple food and traditional crop of the Pacific and an underutilized crop elsewhere. The tropical regions with climates hospitable to breadfruit are also home to about 80% of the world’s hungry and a stable, nutritious, high-yielding, locally grown, non-GMO food crop would make an enormous difference for hundreds of millions of people. From 2005-2016, PlantSMART developed methods of propagating the trees through plant tissue culture that have brought the crop into world markets as a sustainable staple food source. Breadfruit trees require minimal agricultural input, begin bearing fruit in two to three years, and are productive for many decades. A single breadfruit tree produces 250-400 kg of nutritious fruit per year that can be roasted, boiled, dried, pickled, fermented into beer, fried into chips or ground into flour and used in baking. You can now buy breadfruit in Canada both in the fresh produce and gluten-free flour sections of local grocery stores.

Current PlantSMART research is discovering non-food applications of breadfruit such as cosmetic ingredients and natural biopolymers for plastics. Methods for the extraction of raw materials, ingredients and oils of breadfruit have recently been developed. Several companies have evolved from PlantSMART research. Global Breadfruit propagates and distributes elite varieties of breadfruit to tropical countries. To date, Global Breadfruit has planted >145,000 breadfruit trees in 45 countries for food security and modern food products. The Breadfruit Food Company Ltd, is developing breadfruit flour and ingredients from breadfruit for the food industry and Altilis Beauty, is a line of cosmetics made with breadfruit ingredients. PlantSMART basic research in plant chemistry is being applied to create high quality products for world markets.

Selected Publications & Presentations

Google Scholar

 

Apologies, but no results were found.