Functional Genomic Investigation of Aromatic Aminotransferases Involved in Ephedrine Alkaloid Biosynthesis in Ephedra Sinica (Stapf)

Publication Year:
2012
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Repository URL:
https://ir.lib.uwo.ca/etd/1045; https://ir.lib.uwo.ca/cgi/viewcontent.cgi?article=2366&context=etd
Author(s):
Kilpatrick, Korey G
Tags:
Aminotransferase; Ephedra sinica; ephedrine alkaloids; functional genomics; medicinal plants; next-generation sequencing; Genetics and Genomics; Molecular Biology
article description
Ephedra sinica (Ephedraceae) is a broom-like shrub cultivated in arid regions of China, Korea and Japan. This medicinal plant accumulates large amounts of the ephedrine alkaloids, including (S)-cathinone, (1R,2S)-norephedrine, (1R,2S)-ephedrine and (1S,2S)-pseudoephedrine in its aerial tissues. These analogues of amphetamine mimic adrenaline and stimulate the sympathetic nervous system. While much is known about their pharmacological properties, the biological mechanisms by which they are synthesized remains largely unknown. A functional genomics platform was established in order to investigate alkaloid biosynthesis. RNA was extracted from Ephedra sinica stems and sequenced by Illumina HiSeq2000 next-generation sequencing. Candidate biosynthetic enzymes were obtained from this EST collection based on similarity to characterized enzymes with similar functions. This portion of the collaborative study is focused on identifying aminotransferase enzymes involved in alkaloid biosynthesis. Two functional aromatic aminotransferase enzymes, possibly involved in ephedrine biosynthesis have been identified. One exhibiting much greater enzymatic activity was chosen for characterization.