Figure 6.

Model for the Regulation of ω-7 Monoene Fatty Acid Production in Arabidopsis Seeds.

MYB115 and MYB118 are induced in the endosperm at the onset of the maturation phase. The master regulator LEC2 activates their transcription, and MYB118 exerts negative feedback regulation on LEC2. MYB115 and MYB118 coordinately trigger the transcription of two soluble ∆9 palmitoyl-ACP desaturases, namely, AAD2 and AAD3. These enzymes catalyze the synthesis of ω-7 monounsaturated fatty acids, which are accumulated at high levels in the oil stored within the endosperm. The transcriptional negative regulatory loop involving LEC2 and MYB118 was previously described by Barthole et al. (2014).