The proposed biosynthetic pathway for cotton terpenoids. G, Gossypol; DMG, gossypol-6,6′-dimethyl ether; HG, hemigossypol; dHG, desoxyhemigossypol; dMHG, desoxyhemigossypol-6-methyl ether; MHG, hemigossypol-6-methyl ether; HH1, 2, 3, 4, heliocides H1, 2, 3, 4; HB1, 2, 3, 4, heliocides B1, 2, 3, 4; HGQ, hemigossypolone; MHGQ, hemigossypolone-6-methyl ether.