Figure 1From: Positive Darwinian selection is a driving force for the diversification of terpenoid biosynthesis in the genus OryzaOryzaTPS1s have diverged to produce three different sesquiterpene product spectra. The enzymes were expressed in E. coli, extracted, and incubated with the substrate (E, E)-farnesyl diphosphate. The resulting terpene products were separated by gas chromatography-mass spectrometry (GC-MS). The traces of the MS detector were shown for ObTPS1, a representative (E)-β-caryophyllene synthase (ECS), for OsTPS1, a representative (E)-β-caryophyllene/germacrene A synthase (EGS), and for OrTPS1, the germacrene D & germacrene A synthase (DAS). Products were identified as 1, β-elemene; 2, (E)-β-caryophyllene; 3, α-humulene; 4, germacrene D by comparison of their retention times and mass spectra to those of authentic standards. *Unidentified sesquiterpenoids. The chemical structures of compounds 1, 2 and 4 were shown on the right. Note: β-elemene was produced as a thermal rearrangement product from germacrene A in the GC injector (Additional files 4 and 5).Back to article page