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ARS Home » Pacific West Area » Albany, California » Western Regional Research Center » Bioproducts Research » Research » Publications at this Location » Publication #338428

Research Project: Domestic Production of Natural Rubber and Industrial Seed Oils

Location: Bioproducts Research

Title: Fructan reduction by downregulation of 1-SST in guayule

item DONG, NIU - Non ARS Employee
item DONG, CHEN - Non ARS Employee
item Ponciano, Grisel
item Holtman, Kevin
item Placido, Dante
item Coffelt, Terry
item Whalen, Maureen
item McMahan, Colleen

Submitted to: Industrial Crops and Products
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/19/2017
Publication Date: 5/8/2017
Citation: Dong, N., Dong, C., Ponciano, G.P., Holtman, K.M., Placido, D.F., Coffelt, T.A., Whalen, M.C., McMahan, C.M. 2017. Fructan reduction by downregulation of 1-SST in guayule. Industrial Crops and Products. doi: 10.1016/j.indcrop.2017.04.034.

Interpretive Summary: Parthenium argentatum (guayule) is under development in the US as a source of natural rubber, organic resins, and biofuel feedstock. Increases in rubber yield for the crop could contribute to its economic sustainability. The guayule shrub produces most of its rubber in the winter, at the same time it also stores carbohydrates (fructans). A possible strategy to increasing rubber is to divert some of the some of the carbon from carbohydrate. In this study, we were successful in reducing carbohydrate production by downregulation of a key pathway gene. Even though more sucrose was made available, in greenhouse plants that did not translate to more rubber. This suggests the mechanism that controls rubber production is not induced by higher concentration of carbon (in sucrose form).

Technical Abstract: The natural rubber producing plant Parthenium argentatum (guayule) stores carbohydrates mainly in the form of fructans, which are synthesized and stored in the same tissues at the same time as the rubber polymer. The first committed step to fructan synthesis is catalyzed by sucrose:sucrose-1-fructosyltransferase (1-SST), which was downregulated to test whether reduction of carbohydrate synthesis would divert carbon instead to rubber biosynthesis. Guayule leaf strips were transformed by Agrobacterium-mediated technology, and plants with downregulated 1-SST were evaluated in the laboratory and greenhouse. The plant tissue fructan concentration was reduced significantly, and sucrose concentration increased, especially in root tissues of greenhouse-grown plants. However, increased natural rubber production did not result.