Inferring Roles in Defense from Metabolic Allocation of Rice Diterpenoids[OPEN]
Inferring Roles in Defense from Metabolic Allocation of Rice Diterpenoids[OPEN]
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DOI：
10.1105/tpc.18.00205
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发表时间：
2018-05-01
期刊：
影响因子：
11.6
通讯作者：
Peters, Reuben J.
中科院分区：
文献类型：
--
作者：
Lu, Xuan;Zhang, Juan;Peters, Reuben J.
在它们对微生物感染的反应中，植物部署了一系列天然抗生素产品。从历史上看，这些已被确定其体外抗生素活性的基础上，这留下了开放的问题，其相关性防御植物。来自重要农作物水稻（Oryza sativa）的绝大多数此类天然产物是二萜类化合物，其生物合成通过对映或顺式柯巴基二磷酸（CPP）中间体进行，其是基于其对真菌稻瘟病病原体稻瘟病菌（Magnaporthe）的抗生素活性而分离的。然而，其中syn-CPP合酶Os-CPS 4基因被敲除的水稻植物没有表现出对M.米。在这里，我们表明，敲除或敲低Os-CPS 4实际上降低了对细菌性叶枯病病原体黄单胞菌的易感性。相比之下，对ent-CPP合酶Os-CPS 2基因的遗传操作改变了对两种M.和X.米。尽管依赖于Os-CPS 2或Os-CPS 4从根分泌的二萜类化合物，敲除都没有表现出显着的变化，其根际细菌群落的组成。然而，水稻植物在感染/诱导后向顺式以及对映式CPP衍生的二萜类分配大量的代谢资源。进一步的研究表明Os-CPS 4在真菌非宿主病抗性中发挥作用。因此，检查代谢分配提供了重要的线索，生理功能。
Among their responses to microbial infection, plants deploy an arsenal of natural antibiotic products. Historically these have been identified on the basis of their antibiotic activity in vitro, which leaves open the question of their relevance to defense in planta. The vast majority of such natural products from the important crop plant rice (Oryza sativa) are diterpenoids whose biosynthesis proceeds via either ent- or syn-copalyl diphosphate (CPP) intermediates, which were isolated on the basis of their antibiotic activity against the fungal blast pathogen Magnaporthe oryzae. However, rice plants in which the gene for the syn-CPP synthase Os-CPS4 is knocked out do not exhibit increased susceptibility to M. oryzae. Here, we show that knocking out or knocking down Os-CPS4 actually decreases susceptibility to the bacterial leaf blight pathogen Xanthomonas oryzae. By contrast, genetic manipulation of the gene for the ent-CPP synthase Os-CPS2 alters susceptibility to both M. oryzae and X. oryzae. Despite the secretion of diterpenoids dependent on Os-CPS2 or Os-CPS4 from roots, neither knockout exhibited significant changes in the composition of their rhizosphere bacterial communities. Nevertheless, rice plants allocate substantial metabolic resources toward syn- as well as ent-CPP derived diterpenoids upon infection/induction. Further investigation revealed that Os-CPS4 plays a role in fungal non-host disease resistance. Thus, examination of metabolic allocation provides important clues into physiological function.