ATR4 — Brassica oleracea var. botrytis

Summary

BoATR4 (ATR4, CYP83B1, SUR2) on cauliflower chromosome 8 encodes a cytochrome P450 with oxidoreductase activity, heme and iron binding, and gibberellin-binding capacity. It is associated with indole glucosinolate biosynthesis, auxin (IAA) biosynthesis and homeostasis, tryptophan formation, coumarin and phenylpropanoid anabolism, and raffinose family oligosaccharide biosynthesis. The gene is linked to floral organ morphogenesis, shade avoidance, adventitious root development, defense response by callose deposition, induced systemic resistance, response to insects and red light, and gibberellin-mediated signalling. Associations include plant height, stem elongation, flowering time, fruit ripening, seed development, stamen length, pollen fertility restoration, and hypocotyl morphology. Localisation evidence places the product at the ER membrane, plasma membrane, mitochondria, cytoplasm, and nucleus. Studies of related genes in other species link the family to auxin overproduction phenotypes, indolic glucosinolate biosynthesis, and defense against biotrophic pathogens including powdery mildew.