There are about 150 species of wild roses across Asia, Europe and North America. Seven of these can be found in Quebec-but good luck identifying them! According to Anne Bruneau, a Research Professor in molecular systematics in the Plant Biology Research Institute and the Department of Biological Sciences at Université de Montréal, wild rosebushes belong to one the most problematic groups in plant taxonomy. "Everything that can possibly be complicated in plant classification turns up in Rosa: distinctive features that are difficult to interpret, varying morphology within a single species, or even on a single specimen, complex reproductive systems and evolutionary processes, etc."

Two examples are Rosa rousseauiorum and Rosa williamsii, which are found in the regions of Charlevoix and du Bic, respectively. These plants have long been surrounded by controversy. Some believe they are very similar and that they could be considered a single variety of Rosa blanda, which is more common on the continent. A major study of North American roses by Anne Bruneau and her postdoctoral assistant, Julian Starr, should help decide the matter. Rosa rousseauiorum and Rosa williamsii both appear on the list of species that could be declared threatened or endangered in Quebec. But if the researchers establish that only one widespread species is involved, they would be excluded from the list.

Anne Bruneau's laboratory work is intended to determine precisely the relationships among North American rose species. The latest techniques in molecular biology will be used to compare chloroplast and nuclear DNA sequences, an unlimited source of data for molecular systematics studies. As a rule, the more similar the DNA sequences between species, the closer the relationship between the species. The second part of the study will involve an analysis of two complexes of rose species found in Quebec. "Complex" is taken to mean closely related species that are often very difficult to distinguish from one another based on morphological identification features that are traditionally defined together. To differentiate the species in the complex, the researchers will use highly variable molecular markers. The more closely related the species are, as in a complex, the more important a role the markers could play in identifying similarities.

"Everybody knows roses, and everybody likes them!" Prof. Bruneau notes. "Humans have always had a weakness for them. Yet we know nothing about the evolution of the species. For a taxonomist, this is a big challenge!" At the very least, she hopes to avoid the fate of the Belgian researcher François Crépin, who went mad after working on roses his whole life!

Researcher: Anne Bruneau
Telephone: (514) 872-7301
Funding: Natural Science and Engineering Research Council