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Cutin and suberin represent lipophilic polymers forming plant/environment interfaces in leaves and roots. Despite recent progress in A rabidopsis, there is still a lack on information concerning cutin and suberin synthesis, especially in crops. Based on sequence homology, we isolated two c DNA clones of new cytochrome P450s, CYP77 A19 and CYP77 A20 from potato tubers ( S olanum tuberosum). Both enzymes hydroxylated lauric acid ( C12:0) on position ω-1 to ω-5. They oxidized fatty acids with chain length ranging from C12 to C18 and catalysed hydroxylation of 16-hydroxypalmitic acid leading to dihydroxypalmitic (DHP) acids, the major C16 cutin and suberin monomers. CYP77 A19 also produced epoxides from linoleic acid ( C18:2). Exploration of expression pattern in potato by RT-q PCR revealed the presence of transcripts in all tissues tested with the highest expression in the seed compared with leaves. Water stress enhanced their expression level in roots but not in leaves. Application of methyl jasmonate specifically induced CYP77 A19 expression. Expression of either gene in the A rabidopsis null mutant cyp77a6-1 defective in flower cutin restored petal cuticular impermeability. Nanoridges were also observed in CYP77 A20-expressing lines. However, only very low levels of the major flower cutin monomer 10,16-dihydroxypalmitate and no C18 epoxy monomers were found in the cutin of the complemented lines. [ABSTRACT FROM AUTHOR]