Genetic elucidation of interconnected antibiotic pathways mediating maize innate immunity
Genetic elucidation of interconnected antibiotic pathways mediating maize innate immunity
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介导玉米先天免疫的相互关联的抗生素途径的遗传阐明
DOI：
10.1038/s41477-020-00787-9
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发表时间：
2020-10-26
期刊：
影响因子：
18
通讯作者：
Huffaker, Alisa
中科院分区：
文献类型：
--
作者：
Ding, Yezhang;Weckwerth, Philipp R.;Huffaker, Alisa
专门的代谢物构成了免疫的关键层，是作物抗病性的基础；然而，解决途径方面的挑战限制了我们对这些代谢物的功能和应用的理解。在玉米（Zea mays）中，酸性萜类化合物的诱导积累越来越被认为是有助于抗病性的防御机制。在这里，为了了解玉米抗生素的生物合成，我们整合了关联图谱、泛基因组多组学相关性、酶结构功能研究和靶向诱变。我们在三个玉米蛋白 (Zx) 基因簇中定义了 10 个基因，编码四种倍半萜合酶和六种细胞色素 P450 蛋白，共同驱动多种抗生素混合物的产生。产生玉米蛋白（ZX）的能力被阻断的四重突变体表现出广谱抗病性丧失。确保途径对单一无效突变的弹性的遗传冗余与酶底物混杂相结合，创建了一个生物合成沙漏途径，该途径使用不同的底物和体内组合化学来产生复杂的抗生素混合物。阐明的抗病性生化表型的遗传基础表明了玉米的主要防御途径，并为在作物之间转移化学免疫的创新策略提供了信息。在玉米中，一套全面的方法使作者能够分析萜类化合物玉米素类的生物合成途径，并表征这些抗生素化合物在抗病性中的作用。
Specialized metabolites constitute key layers of immunity that underlie disease resistance in crops; however, challenges in resolving pathways limit our understanding of the functions and applications of these metabolites. In maize (Zea mays), the inducible accumulation of acidic terpenoids is increasingly considered to be a defence mechanism that contributes to disease resistance. Here, to understand maize antibiotic biosynthesis, we integrated association mapping, pan-genome multi-omic correlations, enzyme structure-function studies and targeted mutagenesis. We define ten genes in three zealexin (Zx) gene clusters that encode four sesquiterpene synthases and six cytochrome P450 proteins that collectively drive the production of diverse antibiotic cocktails. Quadruple mutants in which the ability to produce zealexins (ZXs) is blocked exhibit a broad-spectrum loss of disease resistance. Genetic redundancies ensuring pathway resiliency to single null mutations are combined with enzyme substrate promiscuity, creating a biosynthetic hourglass pathway that uses diverse substrates and in vivo combinatorial chemistry to yield complex antibiotic blends. The elucidated genetic basis of biochemical phenotypes that underlie disease resistance demonstrates a predominant maize defence pathway and informs innovative strategies for transferring chemical immunity between crops.In maize, a comprehensive set of approaches enabled the authors to analyse the biosynthetic pathway of the zealexin group of terpenoids and characterize the role of these antibiotic compounds in disease resistance.