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United States Department of Agriculture

Agricultural Research Service

Research Project: Improvement and Utilization of Natural Rubber- and Castor Oil-producing Industrial Crops

Location: Crop Improvement & Utilization Research

Title: Expression of the cytoplasmic mevalonate pathway in chloroplasts to reduce substrate limitations for cytoplasmically-produced terpenoid secondary products

Authors
item Cornish, Katrina -
item Kumar, Shashi -
item McMahan, Colleen
item Whalen, Maureen

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: January 29, 2013
Publication Date: May 8, 2013
Citation: Cornish, K., Kumar, S., Mcmahan, C.M., Whalen, M.C. 2013. Expression of the cytoplasmic mevalonate pathway in chloroplasts to reduce substrate limitations for cytoplasmically-produced terpenoid secondary products [abstract]. 3rd International Symposium on Chloroplast Genomics and Genetic Engineering (ISCGGE) Conference, May 8-11, 2013, Brunswich, New Jersey.

Technical Abstract: All products of isoprenoid metabolism originate with the C5 non-allylic substrate, isopentenyl pyrophosphate (IPP). IPP is produced in plants by two distinct pathways, the mevalonate pathway (MEV) in the cytosol and the 2 C methyl-D-erythritol 4 phosphate (MEP) pathway in plastids. A multi-gene approach was employed to insert and express the entire MEV pathway into the tobacco chloroplast genome. Molecular analysis confirmed the site-specific insertion of seven transgenes and homoplasmy. Functionality was demonstrated by unimpeded, healthy, growth on the MEP pathway inhibitor, fosmidomycin. Transplastomic plants containing the MEV pathway genes accumulated higher levels of mevalonate, carotenoids, squalene, sterols and triacyglycerols than control plants. These plants set fertile seed, and three generations of plants have been generated. This is the first time an entire eukaryotic pathway has been transplastomically expressed in plants. This may prove an important tool to redirect metabolic fluxes in the isoprenoid biosynthesis pathway and a viable multigene strategy for engineering metabolism in plants.

Last Modified: 9/2/2014
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