Component of the monoterpenoid indole alkaloids (MIAs, e.g. echitovenine, tabersonine, lochnericine, 19-hydroxytabersonine and horhammericine) biosynthetic pathway; MIAs are used in cancer treatment and other medical applications (PubMed:31009114). Acyltransferase catalyzing the conversion of horhammericine to 19-O-acetylhorhammericine, of 19-hydroxytabersonine to 19-O-acetyltabersonine and of minovincinine to echitovenine (PubMed:29438577, PubMed:31009114). acetyl-CoA + horhammericine = 19-O-acetylhorhammericine + CoA (-)-(R)-19-hydroxytabersonine + acetyl-CoA = (-)-(R)-19-O-acetyltabersonine + CoA (-)-minovincinine + acetyl-CoA = (-)-echitovenine + CoA Alkaloid biosynthesis. Monomer. Confined to roots. Induced by jasmonic acid (MeJA). Belongs to the plant acyltransferase family.