Fig. 7
From: Transcriptomic analyses of cacao flavonoids produced in photobioreactors
Proposed model of the flavonoid transcriptional regulation in cacao cells under light treatments in photobioreactors. Left panel: White light stimulates cell growth and the upregulation of flavonoid structural genes mediated by COP1/HY5 light signaling pathway. Central panel: Shift to blue light, COP1/HY5 continues to drive flavonoid biosynthesis. MYB12 (as part of the MBW complex) mediates between light and flavonoids. ADO1 (blue receptor), GI (circadian rhythm) and two-component regulators ARRs (hormone signaling) possibly interact to mediate flavonoid biosynthesis. Right panel: Long term exposure to blue light induces COP1/HY5 pathway, as well as oxidative stress pathways ascorbate, glutathione, and two-component regulators. At the bottom, ROS production from chloroplast generates an excess of H2O2 stimulating flavonoid production early in the timecourse. H2O2 accumulation is detoxified by enzymatic (SOD, APX, MIOX, PERs) and non-enzymatic (flavonoids) mechanisms during and at the end of the experiment. Dotted ovals are candidate genes in the light network. PHYs, CRYs, UVR8, and ZTL are colored according to specific light qualities