Figure 4

Brief overview of the ABA pathway (inferred by KEGG, [45]). On the left side the β-carotene biosynthesis steps. On the right the ABA-dedicated enzymatic reactions. Several probe sets related to ABA synthesis enzymes (PSY, LYC- β, β-OHase, NCED) were up-regulated by drought stress. Their expression levels based on array data are showed in the corresponding histograms. 2.5.1.32 = Phytoene synthase (PSY); 1.14.99.-= Phytoene desaturase (PDS); 1.14.99.30 = ζ-carotene desaturase (ZDS); 1.14.-.-= Lycopene β-cyclase (LYC-β); 1.14.13.- = β-carotene hydroxylase (β-OHase); 1.10.99.3 = Violaxanthin de-epoxidase (NPQ1); 1.14.13.90 = Zeaxanthin epoxidase (ZEP); 1.13.11.51 = 9-cis-epoxycarotenoid dioxygenase (NCED); 1.1.1.288 = xanthoxin dehydrogenase (ABA2); 1.2.3.14 = Abscisic aldehyde oxidase (AAO).