Figure 1.
Biosynthesis of carotenoids starts with the 2-C-methyl-d-erythritol 4-phosphate (MEP) pathway leading to the formation of IPP, continues with the isoprenoid pathway to obtain GGPP.
The first committed step to the synthesis of carotenoids consists of the head to head condensation of 2 GGPP to form phytoene. The enzymes in bold letters denote enzyme targets that were tested in this study.
Figure 2.
Schematics of the synthesis of 5-ethoxyclomazone, ketoclomazone and keto analogs 1 and 2.
Figure 3.
Time-dependent phytoene accumulation in barley (Hordeum vulgare L.) exposed to 200 µM norflurazon.
Data represent means of three replications with standard deviation.
Figure 4.
Dose-response curves showing the effect of the herbicide clomazone with (○) and without (•) phorate on phytoene accumulation induced by 200 µM norflurazon.
(A) Green and (B) greening etiolated young barley leaves. Data represent means of three replications with standard deviation.
Figure 5.
Dose-response curves of (A) 5-ethoxyclomazone and (B) ketoclomazone with (○) and without (•) phorate on greening etiolated barley leaves.
Phytoene was caused to accumulate by the presence of 200 µM norflurazon. Data represent means of three replications with standard deviation.
Figure 6.
Dose-response curves of the DXR inhibitors fosmidomycin (•)and FR-900098 (○) on greening etiolated barley leaves.
Phytoene accumulation was induced in the presence of 200 µM norflurazon. Data represent means of three replications with standard deviation.
Table 1.
Effect of BASF experimental compounds on phytoene accumulation in the presence of 200 µM norflurazon.
Table 2.
Effect of herbicides with different modes of action on phytoene accumulation in the presence of 200 µM norflurazon.