Elicited cell suspension cultures of apple (Malus x domestica) cv. Libertyproduce biphenyl phytoalexins

Yeast extract treated cell suspension cultures from a scab (Venturia inaequ alis) resistant apple cultivar, Malus x domestica cv. Liberty produce diben zofuran and biphenyl compounds as part of their defense system against fung al invasion. We have isolated and identified three biphenyl derivatives, 4- hydroxy-3,5-dimethoxybiphenyl (aucuparin), 2',4,-dihydroxy-3,5-dimethoxybip henyl (2'-hydroxy-aucuparin) and 2'-O-beta-D-glucopyranosyl-4-hydroxy-3,5-m ethoxybiphenyl (2'-o-beta-D-glucopyranosylaucuparin) from the cells and the medium and show here their chemical properties. Although this is the first identification of 2'-glucopyranosylaucuparin, its aglycone, 2'-hydroxyaucu parin and aucuparin have been reported previously [Kokubun, T., Harborne, J .B., Phytochemistry, 1995, 40, 1649-1654.] from fungus infected wood of Mal us species. Production of an array of dibenzofuran and biphenyl derivatives in response to fungal attack may he an important part of the disease resis tance mechanism of scab resistant apple cultivars. (C) 1998 Elsevier Scienc e Ltd. All rights reserved.