Institut für Pharmazeutische Biologie, Technische Universität Braunschweig, Mendelssohnstr. 1, 38106 Braunschweig, Germany.
Beilstein J Org Chem. 2012;8:613-20. doi: 10.3762/bjoc.8.68. Epub 2012 Apr 20.
Biphenyls and dibenzofurans are the phytoalexins of the Pyrinae, a subtribe of the plant family Rosaceae. The Pyrinae correspond to the long-recognized Maloideae. Economically valuable species of the Pyrinae are apples and pears. Biphenyls and dibenzofurans are formed de novo in response to infection by bacterial and fungal pathogens. The inducible defense compounds were also produced in cell suspension cultures after treatment with biotic and abiotic elicitors. The antimicrobial activity of the phytoalexins was demonstrated. To date, 10 biphenyls and 17 dibenzofurans were isolated from 14 of the 30 Pyrinae genera. The most widely distributed compounds are the biphenyl aucuparin and the dibenzofuran γ-cotonefuran. The biosynthesis of the two classes of defense compounds is not well understood, despite the importance of the fruit crops. More recent studies have revealed simultaneous accumulation of biphenyls and dibenzofurans, suggesting sequential, rather than the previously proposed parallel, biosynthetic pathways. Elicitor-treated cell cultures of Sorbus aucuparia served as a model system for studying phytoalexin metabolism. The key enzyme that forms the carbon skeleton is biphenyl synthase. The starter substrate for this type-III polyketide synthase is benzoyl-CoA. In apples, biphenyl synthase is encoded by a gene family, members of which are differentially regulated. Metabolism of the phytoalexins may provide new tools for designing disease control strategies for fruit trees of the Pyrinae subtribe.
联苯和二苯并呋喃是蔷薇科 Pyrinae 亚科的植物抗毒素。 Pyrinae 对应于长期公认的 Maloideae。 Pyrinae 中经济价值高的物种是苹果和梨。联苯和二苯并呋喃是在细菌和真菌病原体感染时新形成的。在经过生物和非生物诱导剂处理后，细胞悬浮培养物中也产生了诱导防御化合物。已证明植物抗毒素具有抗菌活性。迄今为止，已从 30 个 Pyrinae 属中的 14 个属中分离出 10 个联苯和 17 个二苯并呋喃。分布最广的化合物是联苯 aucuparin 和二苯并呋喃 γ-考酮呋喃。尽管水果作物很重要，但这两类防御化合物的生物合成仍未得到很好的理解。最近的研究揭示了联苯和二苯并呋喃的同时积累，表明存在顺序而不是先前提出的平行生物合成途径。用生物诱导剂处理悬钩子属细胞培养物作为研究植物抗毒素代谢的模型系统。形成碳骨架的关键酶是联苯合酶。这种 III 型聚酮合酶的起始底物是苯甲酰辅酶 A。在苹果中，联苯合酶由一个基因家族编码，该家族成员的表达受到差异调控。植物抗毒素的代谢可能为 Pyrinae 亚科的果树设计疾病控制策略提供新的工具。
