Among the myriad specialized metabolites that plants employ to mediate interactions with their environment, diterpenoids form a chemically diverse group with vital biological functions. A few broadly abundant diterpenoids serve as core pathway intermediates in plant general metabolism. The majority of plant diterpenoids, however, function in specialized metabolism as often species-specific chemical defenses against herbivores and microbial diseases, in below-ground allelopathic interactions, as well as abiotic stress responses. Dynamic networks of anti-microbial diterpenoids were first demonstrated in rice (Oryza sativa) over four decades ago, and more recently, unique diterpenoid blends with demonstrated antibiotic bioactivities were also discovered in maize (Zea mays). Enabled by advances in -omics and biochemical approaches, species-specific diterpenoid-diversifying enzymes have been identified in these and other Poaceous species, including wheat (Triticum aestivum) and switchgrass (Panicum virgatum), and are discussed in this article with an emphasis on the critical diterpene synthase and cytochrome P450 monooxygenase families and their products. The continued investigation of the biosynthesis, diversity, and function of terpenoid-mediated crop defenses provides foundational knowledge to enable the development of strategies for improving crop resistance traits in the face of impeding pest, pathogen, and climate pressures impacting global agricultural production.

中文翻译：

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单子叶植物中的特殊二萜代谢：生物合成和化学多样性

在植物用来介导与环境相互作用的无数特殊代谢物中，二萜类化合物形成了一个具有重要生物学功能的化学多样性群。一些广泛丰富的二萜类化合物作为植物一般代谢的核心途径中间体。然而，大多数植物二萜类化合物在专门的代谢中发挥作用，通常是针对食草动物和微生物疾病的物种特异性化学防御、地下化感相互作用以及非生物胁迫反应。四十多年前，抗微生物二萜类化合物的动态网络首次在水稻（Oryza sativa）中得到证明，最近，在玉米（Zea mays）中也发现了具有证明抗生素生物活性的独特二萜类混合物。得益于组学和生化方法的进步，物种特异性二萜多样化酶已在这些和其他禾本科物种中得到鉴定，包括小麦 (Triticum aestivum) 和柳枝稷 (Panicum virgatum)，本文将重点讨论关键的二萜合酶和细胞色素 P450 单加氧酶家族和他们的产品。对萜类化合物介导的作物防御的生物合成、多样性和功能的持续研究提供了基础知识，有助于制定战略，以在面临影响全球农业生产的害虫、病原体和气候压力的情况下改善作物抗性性状。并在本文中重点讨论关键的二萜合酶和细胞色素 P450 单加氧酶家族及其产品。对萜类化合物介导的作物防御的生物合成、多样性和功能的持续研究提供了基础知识，有助于制定战略，以在面临影响全球农业生产的有害生物、病原体和气候压力的情况下改善作物抗性性状。并在本文中重点讨论关键的二萜合酶和细胞色素 P450 单加氧酶家族及其产品。对萜类化合物介导的作物防御的生物合成、多样性和功能的持续研究提供了基础知识，有助于制定战略，以在面临影响全球农业生产的有害生物、病原体和气候压力的情况下改善作物抗性性状。