Page 193 - PC2019 Program & Proceedings

PLANT CANADA 2019

S171. Effect of methyl jasmonate on terpene/cannabinoid biosynthesis and suppression of gray
mold in Cannabis sativa L.
Cormier, C.; C. Balthazar; A. Cull; D. Joly
Université de Moncton

Supplying cannabis to a legalized market represents a major economic opportunity. Indeed, the retail
market value in Canada is expected to reach $8.7 billion annually. However, cannabis being one of the
most widely used illicit drugs excluded it from research programs that have led to massive increases in
yields in other crops. Supply shortages are plaguing the industry, and cultivation often faces important
phytosanitary problems due to diseases like powdery mildew and gray mold (Botrytis cinerea Pers.).
Cannabinoids and terpenes are important secondary metabolites responsible for the
psychoactive/medicinal effects and aromas of cannabis, respectively. As in other plants, terpenes (and
possibly cannabinoids) also exhibit essential roles in defense against biotic and abiotic stresses. Methyl
jasmonate (MeJA) is an endogenous volatile compound involved in plant defense and developmental
pathways. Here we used RT-qPCR and GC-MS to explore whether MeJA directly impacts the
biosynthesis of terpenes and cannabinoids. Results suggest that certain genes involved in their
biosynthesis, including terpene or cannabinoid synthases, are induced following treatments with MeJA.
We also aimed to determine whether MeJA induces resistance against B. cinerea and reduce disease
incidence in cannabis. Further work is needed to confirm our results, but they suggest that application of
MeJA could play two beneficial roles in cannabis cultivation: a control measure against B. cinerea and a
catalyst to increase the production of cannabinoids and terpenes.

David Joly (david.joly@umoncton.ca)

S172. Increased resistance to potato common scab is associated with changes in the tuber periderm
*
Turcotte, M.A. ; S. Labidi; S. Lerat; N. Beaudoin
University of Sherbrooke

Potato common scab is a major disease affecting potato fields around the world. The disease is
characterized by the formation of scab-like corky lesions on developing tubers. These lesions are mainly
caused by Streptomyces scabies which synthesizes during the infection process the essential toxin
thaxtomin A (TA). TA production is stimulated by suberin and cellobiose. Suberin is a component of the
potato periderm where it plays a role in the protection of tubers against the invasion of microorganisms.
In our laboratory, potato calli of the potato variety Yukon Gold were habituated to increasing
concentrations of TA. Some of the somaclones regenerated from TA-habituated calli were more resistant
to common scab. To identify the changes that contribute to the increased resistance to common scab in the
tubers of these somaclones, we analysed the organisation of their periderm using fluorescence
microscopy. The tuber phellem from resistant somaclones contained more distorted cells and a higher
number of cell layers than the phellem from the original variety. Expression of genes involved in suberin
synthesis and defense responses was analysed by RT-qPCR. Several of those genes showed a higher
expression in the tubers from resistant somaclones compared to those from the original variety. We will
discuss how these changes can contribute to the increased resistance to common scab in the TA-
habituated somaclones.

Marc-Antoine Turcotte (Marc-Antoine.Turcotte3@USherbrooke.ca)

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