Dr Jacqueline C. Bede
jacqueline [dot] bede [at] mcgill [dot] ca (E-mail)
Each year, billions of agricultural and forestry dollars are lost to insect pests, in the form of crop and forest damages and expenses in controlling insects. However, if we had a better understanding of how plants defended themselves, this would allow us to design insect control strategies to enhance the endogenous defense responses of the plant.
In my research, I am looking at the defenses responses of Medicago truncatula, a closely related species to the forage crop alfalfa, to caterpillar herbivory by the generalist pest, Spodoptera exigua, the beet armyworm.
To address this problem, we must understand how plants manipulate their biochemical defense mechanisms. An important aspect of this is determining how genes and their encoded proteins are regulated in response to insect attack. Using differential display and subtractive hybridization techniques, we are looking at the global expression patterns in M. truncatula plants subject to S. exigua larval herbivory. This will not only help us to identify new genes but also understand how these genes are co-regulated. Genes and their products differentially expressed in response to caterpillar herbivory will be characterized at the molecular level and results correlated with physiological responses. By looking at both the regulation of the molecular responses and the changes in metabolic flux through biochemical pathways, our hope is to develop a cohesive picture of how this plant responds to caterpillar herbivory.
Present lab members:
Jamuna Paudel (Ph.D. candidate)
Gongyu Lin (M.Sc. candidate)
Alberto Prado (M.Sc. candidate)
Khash Afshar (M.Sc.)
Taeko Saski (M.Sc.)
Magali Merkx-Jacques (M.Sc.)
Shireef Darwish (M.Sc.)
Undergraduate and graduate student co-authors are in bold
Weech, MH, Chapleau, M, Pan, L, Ide, C and Bede, JC. 2008. Caterpillar saliva interferes with induced Arabidopsis thaliana defense responses via the systemic acquired resistance pathway. Journal of Experimental Botany. 59: 2437-2448.
Darwish, S, Pan, L, Ide, C and Bede, JC. 2008. Caterpillar-specific gene expression in Medicago trucatula. Plant Molecular Biology Reporter 26: 12-31.
Bede, JC, Musser, RO, Felton, GW and Korth, KL. 2006. Caterpillar herbivory and salivary enzymes decrease transcript levels of Medicago truncatula genes encoding early enzymes in terpenoid biosynthesis. Plant Molecular Biology 60: 519-530.
Gomez, SK, Cox, MM, Bede, JC, Inoue, K, Alborn, HT, Tumlinson, JH and Korth, KL 2005. Lepidopteran herbivory and oral factors induce transcripts encoding novel terpene synthases in Medicago truncatula. Arch. Insect Biochem. Physiol. 58:114-127.
Babic, B, Poisson, A, Darwish, S, Lacasse, J, Merkx-Jacques, M, Despland, E and Bede, JC. 2008. Influence of dietary nutritional composition on caterpillar salivary enzyme activity. Journal of Insect Physiology. 54: 286-296.
Merkx-Jacques, M, Despland, E and Bede, JC. 2008. Nutrient utilization by generalist caterpillars of the beet armyworm, Spodoptera exigua. Physiological Entomology. 33: 51-61.
Bede, JC, McNeil, JN, Tobe, SS. 2007. The role of neuropeptides in caterpillar nutritional ecology. Peptides 28: 185-196.