Potato common scab (PCS) is a widespread plant disease that lacks effective control measures. Using a small molecule elicitor, we activate the production of a novel class of polyketide antibiotics, streptolateritic acids A–D, in Streptomyces sp. FXJ1.172. These compounds show a promising control efficacy against PCS and an unusual acyclic pentacarboxylic acid structure. A gene cluster encoding a type I modular polyketide synthase is identified to be responsible for the biosynthesis of these metabolites. A cytochrome P450 (CYP) and an aldehyde dehydrogenase (ADH) encoded by two genes in the cluster are proposed to catalyze iterative oxidation of the starter-unit-derived methyl group and three of six branching methyl groups to carboxylic acids during chain assembly. Our findings highlight how activation of silent biosynthetic gene clusters can be employed to discover completely new natural product classes able to combat PCS and new types of modular polyketide synthase-based biosynthetic machinery.

中文翻译：

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链土酸 A–D 的发现和生物合成：来自链霉菌属的无环五羧酸。 FXJ1.172 具有对抗马铃薯赤霉病的良好活性


马铃薯赤霉病（PCS）是一种广泛传播的植物病害，缺乏有效的防治措施。使用小分子引发剂，我们激活了链霉菌属中一类新型聚酮化合物抗生素链红土酸 A–D 的产生。 FXJ1.172。这些化合物显示出对 PCS 的有希望的控制功效和不寻常的无环五羧酸结构。编码 I 型模块化聚酮合酶的基因簇被鉴定为负责这些代谢物的生物合成。簇中两个基因编码的细胞色素 P450 (CYP) 和乙醛脱氢酶 (ADH) 被认为在链组装过程中催化起始单元衍生的甲基和六个分支甲基中的三个重复氧化为羧酸。我们的研究结果强调了如何利用沉默生物合成基因簇的激活来发现能够对抗 PCS 的全新天然产物类别以及基于模块化聚酮合酶的新型生物合成机制。