Phytogeographic and genetic variation in Sorbus, a traditional antidiabetic medicine-adaptation in action in both a plant and a discipline.

PeerJ. 2016 Nov 3;4:e2645. eCollection 2016.

Bailie A¹, Renaut S², Ubalijoro E³, Guerrero-Analco JA⁴, Saleem A⁵, Haddad P⁶, Arnason JT⁵, Johns T⁷, Cuerrier A⁸.

• ¹Department of Plant Science, McGill University, Ste-Anne-de-Bellevue, QC, Canada; Jardin Botanique de Montréal, Institut de Recherche en Biologie Végétale, Montreal, QC, Canada.
• ²Département de Sciences Biologiques, Institut de Recherche en Biologie Végétale, Université de Montréal , Montreal , QC , Canada.
• ³Institute for the Study of International Development, McGill University , Montreal , QC , Canada.
• ⁴Department of Biology, University of Ottawa, Ottawa, ON, Canada; Red de Estudios Moleculares Avanzados, Instituto de Ecología A.C, Xalapa, Veracruz, Mexico.
• ⁵Department of Biology, University of Ottawa , Ottawa , ON , Canada.
• ⁶Département de Pharmacologie, University of Montreal , Montreal , QC , Canada.
• ⁷Department of Plant Science, McGill University, Ste-Anne-de-Bellevue, QC, Canada; School of Dietetics and Human Nutrition, McGill University, Ste-Anne-de-Bellevue, QC, Canada.
• ⁸Jardin Botanique de Montréal, Institut de Recherche en Biologie Végétale , Montreal , QC , Canada.

Abstract

Mountain ash (Sorbus decora and S. americana) is used by the Cree Nation of the James Bay region of Quebec (Eeyou Istchee) as traditional medicine. Its potential as an antidiabetic medicine is thought to vary across its geographical range, yet little is known about the factors that affect its antioxidant capacity. Here, we examined metabolite gene expression in relation to antioxidant activity, linking phytochemistry and medicinal potential. Samples of leaf and bark from S. decora and S. americana were collected from 20 populations at four different latitudes. Two genes known to produce antidiabetic substances, flavonol synthase and squalene synthase, were analyzed using quantitative real time PCR. Gene expression was significantly higher for flavonol synthase compared to squalene synthase and increased in the most Northern latitude. Corresponding differences observed in the antioxidant capacity of ethanolic extracts from the bark of Sorbus spp. confirm that plants at higher latitudes increase production of stress-induced secondary metabolites and support Aboriginal perceptions of their higher medicinal potential. Modern genetic techniques such as quantitative real time PCR offer unprecedented resolution to substantiate and scrutinise Aboriginal medicinal plant perception. Furthermore, it offers valuable insights into how environmental stress can trigger an adaptive response resulting in the accumulation of secondary metabolites with human medicinal properties.

KEYWORDS:

Adaptation; Antioxidant; Ethnobotany; Phytochemistry; Quantitative rtPCR; Sorbus