Laticifer-specific cis-prenyltransferase silencing affects the rubber, triterpene, and inulin content of taraxacum brevicorniculatum
Post, J., van Deenen, N., Fricke, J., Kowalski, N., Wurbs, D., Schaller, H., Eisenreich, W., Huber, C., Twyman, Richard M., Prufer, D. and Gronover, C. S.. (2012) Laticifer-specific cis-prenyltransferase silencing affects the rubber, triterpene, and inulin content of taraxacum brevicorniculatum. Plant Physiology, Vol.158 (No.3). pp. 1406-1417. ISSN 0032-0889Full text not available from this repository.
Official URL: http://dx.doi.org/10.1104/pp.111.187880
Certain Taraxacum species, such as Taraxacum koksaghyz and Taraxacum brevicorniculatum, produce large amounts of high-quality natural rubber in their latex, the milky cytoplasm of specialized cells known as laticifers. This high-molecular mass biopolymer consists mainly of poly(cis-1,4-isoprene) and is deposited in rubber particles by particle-bound enzymes that carry out the stereospecific condensation of isopentenyl diphosphate units. The polymer configuration suggests that the chain-elongating enzyme (rubber transferase; EC 18.104.22.168) is a cis-prenyltransferase (CPT). Here, we present a comprehensive analysis of transgenic T. brevicorniculatum plants in which the expression of three recently isolated CPTs known to be associated with rubber particles (TbCPT1 to -3) was heavily depleted by laticifer-specific RNA interference (RNAi). Analysis of the CPT-RNAi plants by nuclear magnetic resonance, size-exclusion chromatography, and gas chromatography-mass spectrometry indicated a significant reduction in rubber biosynthesis and a corresponding 50% increase in the levels of triterpenes and the main storage carbohydrate, inulin. Transmission electron microscopy revealed that the laticifers in CPT-RNAi plants contained fewer and smaller rubber particles than wild-type laticifers. We also observed lower activity of hydroxymethylglutaryl-coenzyme A reductase, the key enzyme in the mevalonate pathway, reflecting homeostatic control of the isopentenyl diphosphate pool. To our knowledge, this is the first in planta demonstration of latex-specific CPT activity in rubber biosynthesis. © 2012 American Society of Plant Biologists.
|Item Type:||Journal Article|
|Subjects:||Q Science > Q Science (General)|
|Divisions:||Faculty of Science > Life Sciences (2010- ) > Biological Sciences ( -2010)|
|Journal or Publication Title:||Plant Physiology|
|Publisher:||American Society of Plant Biologists|
|Page Range:||pp. 1406-1417|
|Access rights to Published version:||Restricted or Subscription Access|
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