Investigation of the potential for triterpene synthesis in rice through genome mining and metabolic engineering
Article first published online: 18 APR 2011
© 2011 The Authors. New Phytologist © 2011 New Phytologist Trust
Volume 191, Issue 2, pages 432–448, July 2011
How to Cite
Inagaki, Y.-S., Etherington, G., Geisler, K., Field, B., Dokarry, M., Ikeda, K., Mutsukado, Y., Dicks, J. and Osbourn, A. (2011), Investigation of the potential for triterpene synthesis in rice through genome mining and metabolic engineering. New Phytologist, 191: 432–448. doi: 10.1111/j.1469-8137.2011.03712.x
- Issue published online: 29 JUN 2011
- Article first published online: 18 APR 2011
- Received: 30 December 2010, Accepted: 28 February 2011
- cytochrome P450;
- disease resistance;
- gene cluster;
- genome mining;
- metabolic engineering;
- oxidosqualene cyclase;
- •The first committed step in sterol biosynthesis in plants involves the cyclization of 2,3-oxidosqualene by the oxidosqualene cyclase (OSC) enzyme cycloartenol synthase. 2,3-Oxidosqualene is also a precursor for triterpene synthesis. Antimicrobial triterpenes are common in dicots, but seldom found in monocots, with the notable exception of oat. Here, through genome mining and metabolic engineering, we investigate the potential for triterpene synthesis in rice.
- •The first two steps in the oat triterpene pathway are catalysed by a divergent OSC (AsbAS1) and a cytochrome P450 (CYP51). The genes for these enzymes form part of a metabolic gene cluster. To investigate the origins of triterpene synthesis in monocots, we analysed systematically the OSC and CYP51 gene families in rice. We also engineered rice for elevated triterpene content.
- •We discovered a total of 12 OSC and 12 CYP51 genes in rice and uncovered key events in the evolution of triterpene synthesis. We further showed that the expression of AsbAS1 in rice leads to the accumulation of the simple triterpene, β-amyrin.
- •These findings provide new insights into the evolution of triterpene synthesis in monocots and open up opportunities for metabolic engineering for disease resistance in rice and other cereals.