Christendat Lab

Cell and Systems Biology, University of Toronto

Regulation of shikimate pathways in plants

We have recently identified a key regulatory point of the shikimate pathway in plants (manuscript submitted). We have demonstrated that the aromatic amino acids Tyrosine and Phenylalanine feedback inhibit the pathway flux resulting in attenuation of secondary metabolites biosynthesis. We have exclusively focused on tyrosine regulation because it has shown to affect the accumulation of both Tyrosine and Phenylalanine. There is tremendous interest in both of these compounds; tyrosine derived metabolites is important for biotechnological applications including manufacturing of morphine derivatives. Phenylalanine serves as a precursor for numerous phenylpropanoids metabolite. Specifically, we have determined that overexpression of specific shikimate pathway enzyme results in about 10-fold increased in the amount of phenylalanine produced in plants. Our next goal is to determine how to modulate this pathway in crop plants and other plants of biotechnological interest to improve lignin and secondary metabolites production.
To apply sophisticated biological and biochemical approaches to we address specific biological and biochemical on the evolutionary relationship of shikimate pathway enzymes and their mechanism of regulation in Arabidopsis with emphasis on the enzymes DAHP synthase (DAHPS), shikimate dehydrogenase (SDH) and shikimate kinase (SK). The shikimate pathway produces chorismate, a precursor for aromatic compounds including isoflavonoids, phenylpropanoids, lignin, hormones etc [1-3]. Isoflavonoids and phenylpropanoids have a wide range of health benefits because of their powerful antioxidant properties. The pathway also has important biotechnological applications [4]. Absent in animals, but essential in plants and microbes, the shikimate pathway is an ideal target for the development of herbicide and anti-microbial agents [5]. The shikimate pathway is highly regulated due to its essential role in secondary metabolite biosynthesis but is not well understood in plants. This proposal will build on our progress in three main areas of the shikimate pathway.

A general overview of the shikimate pathway and its regulation. Figure includes certain derivatives of the pathway that can be produced via different precursors. Figure by Victor Tulceanu.


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