Dirigent proteins impart stereoselectivity on the phenoxy radical-coupling reaction, yielding optically active lignans from two molecules of coniferyl alcohol in the biosynthesis of lignans, flavonolignans, and alkaloids and thus plays a central role in plant secondary metabolism (By similarity). Regulates suberin accumulation in roots. Homodimer. In roots, mostly detected in root endodermis and quiescent center, and, to a lower extent, in root stele and cortex. Expressed in root vascular cylinder, flowers, siliques, cotyledon and leaf veins, and leaf margins. Present in the basal region of rosette leaf trichomes and in developing xylem. In flowers, localized to vasculature of the stamen filament, in anthers and papillar cells of the stigma. In siliques, mostly expressed in the abscission zone. Increased root suberin accumulation characterized by an increased aliphatic monomer content in suberin. Reduced day time transpiration rates and increased water-use efficiency during the vegetative growth period. Decreases in the accumulation of Ca, Mn, and Zn and increases in the accumulation of Na, S, K, As, Se, and Mo in the shoot. Belongs to the plant dirigent protein family.