Investigation of the potential for triterpene synthesis in rice through genome mining and metabolic engineering

Yoshi-Shige Inagaki, Graham Etherington, Katrin Geisler, Ben Field, Melissa Dokarry, Kousuke Ikeda, Yukako Mutsukado, Jo Dicks, Anne Osbourn

Research output: Contribution to journalArticle

34 Citations (Scopus)

Abstract

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.
Original languageEnglish
Pages (from-to)432-448
Number of pages17
JournalNew Phytologist
Volume191
Issue number2
Early online date18 Apr 2011
DOIs
Publication statusPublished - Jul 2011

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