Involved in the biosynthesis of germacrene-derived sesquiterpene lactones (PubMed:30468448). Hydroxylates germacrene A acid to 8-beta-hydroxy-germacrene A acid (PubMed:21515683, PubMed:29758164). Unlike 6-alpha-hydroxy-germacrene A acid, this compound cannot undergo spontaneous lactonization (PubMed:21515683, PubMed:29758164). germacra-1(10),4,11(13)-trien-12-oate + O2 + reduced [NADPH--hemoprotein reductase] = 8beta-hydroxygermacra-1(10),4,11(13)-trien-12-oate + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] Secondary metabolite biosynthesis; terpenoid biosynthesis. Expressed in leaf primordia. In developing leaves, expressed at very low levels in young leaf primordia, but strongly induced after the fourth and fifth days following leaf primordia initiation. Belongs to the cytochrome P450 family.