Biosynthesis, elicitation and roles of monocot terpenoid phytoalexins
Biosynthesis, elicitation and roles of monocot terpenoid phytoalexins
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DOI：
10.1111/tpj.12436
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发表时间：
2014-08-01
期刊：
影响因子：
7.2
通讯作者：
Peters, Reuben J.
中科院分区：
文献类型：
--
作者：
Schmelz, Eric A.;Huffaker, Alisa;Peters, Reuben J.
植物研究的一个长期目标是优化生物化学制剂的保护功能，以阻止害虫和病原体的攻击。近40年前，在水稻中发现了病原体诱导的二萜类化合物，这些化合物被证明具有抗菌植物抗菌素的功能。本文以水稻和玉米为例，讨论了单子叶萜类植物抗毒素的发现、生物合成、提取和功能表征等方面的最新进展。最近已知的萜类植物抗毒素的扩展现在不仅包括与拉丹相关的二萜超家族，还包括卡斯宾型二萜和β -大木匠衍生的四萜类。生物化学方法已被用于将途径前体和最终产物与同源生物合成基因配对。通过谷物基因组注释和萜烯合成酶鉴定的进展，预测的萜类植物抗毒素的数量正在扩大，同样也使发现禾科以外的植物成为可能。在细胞水平上，现在有确凿的证据表明，真菌衍生的几甲壳素激发子的多种植物受体、膜相关信号复合物的磷酸化、丝裂原激活的蛋白激酶的激活、植物激素信号的参与，以及介导植物抗毒素生物合成基因表达和随后途径终产物积累的转录因子的存在。诱导产生的萜类植物抗毒素具有额外的生物学功能，包括根分泌物介导的化感作用和昆虫的拒食活性。这些发现鼓励了对其他相互作用的考虑，这些相互作用模糊了传统上离散的植物抗毒素分类。突变体集合的建立和遗传转化的增加有助于进一步的生物学作用的关键检查。未来的研究方向包括萜类植物抗毒素前体和终产物作为介导植物生理过程的潜在信号的研究。
A long-standing goal in plant research is to optimize the protective function of biochemical agents that impede pest and pathogen attack. Nearly 40 years ago, pathogen-inducible diterpenoid production was described in rice, and these compounds were shown to function as antimicrobial phytoalexins. Using rice and maize as examples, we discuss recent advances in the discovery, biosynthesis, elicitation and functional characterization of monocot terpenoid phytoalexins. The recent expansion of known terpenoid phytoalexins now includes not only the labdane-related diterpenoid superfamily but also casbane-type diterpenoids and beta-macrocarpene-derived sequiterpenoids. Biochemical approaches have been used to pair pathway precursors and end products with cognate biosynthetic genes. The number of predicted terpenoid phytoalexins is expanding through advances in cereal genome annotation and terpene synthase characterization that likewise enable discoveries outside the Poaceae. At the cellular level, conclusive evidence now exists for multiple plant receptors of fungal-derived chitin elicitors, phosphorylation of membrane-associated signaling complexes, activation of mitogen-activated protein kinase, involvement of phytohormone signals, and the existence of transcription factors that mediate the expression of phytoalexin biosynthetic genes and subsequent accumulation of pathway end products. Elicited production of terpenoid phytoalexins exhibit additional biological functions, including root exudate-mediated allelopathy and insect antifeedant activity. Such findings have encouraged consideration of additional interactions that blur traditionally discrete phytoalexin classifications. The establishment of mutant collections and increasing ease of genetic transformation assists critical examination of further biological roles. Future research directions include examination of terpenoid phytoalexin precursors and end products as potential signals mediating plant physiological processes.