Involved in the biosynthesis of the anti-fungal and antibacterial toxins colneleic acid and colnelenic acid. Can use (9S,10E,12Z)-9-hydroperoxy-10,12-octadecadienoic acid (9-HPOD) and (10E,12Z,15Z)-(9S)-9-hydroperoxyoctadeca-10,12,15-trienoic acid (9-HPOT) as substrates but has no activity with the corresponding 13-hydroperoxides. (9S)-hydroperoxy-(10E,12Z)-octadecadienoate = colneleate + H2O Optimum pH is 5.5 - 7.5. Expressed in roots. Up-regulated 6 and 12 hours-post-infection after infiltration with P.syringae pv. maculicola and between 2 and 4 dpi after infection by P.infestans. Belongs to the cytochrome P450 family. 9-divinyl ether synthase subfamily.