Cover illustration: Suberin goes genomics. The biopolyester suberin forms physiological important apoplastic barriers in roots. In Arabidopsis primary roots, suberin depositions can be found in endodermal cell walls as indicated by a red staining with the lipophilic dye Sudan 7B (top). The most prominent suberin monomer in Arabidopsis is the C18:1 ω-hydroxyacid, a product of CYP86A1 catalysis. In a reverse genetics approach CYP86A1 was found to be expressed in the root endodermis (middle). Gas chromatography analysis of suberin of corresponding mutants in this hydroxylase of root suberized tissue (horst) revealed a strong reduction in C16 and C18 ω-hydroxyacids (GC trace overlay). Heterologous expression of CYP86A1-GFP fusions distributed CYP86A1 to the endoplasmic reticulum (bottom), indicating that suberin monomer biosynthesis takes place in this subcellular compartment before intermediates are exported in the apoplast. (Microscopy photographs by I Briesen and M Beck and layout by RB Franke; see Höfer et al., pp. 2347-2360.)
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