Engineered plant control of associative nitrogen fixation.
Engineered plant control of associative nitrogen fixation.
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DOI：
10.1073/pnas.2117465119
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发表时间：
2022-04-19
影响因子：
11.1
通讯作者：
中科院分区：
文献类型：
--
作者：
用固氮（N2固定）细菌接种谷物为农业中施用氮肥提供了一种可持续的替代方法。虽然天然固氮生物已经进化出多层调节机制，将N2固定与产物NH3的同化结合起来，并防止释放到植物中，但遗传修饰可以允许NH3的过量产生和排泄。然而，缺乏严格的宿主特异性根定植的细菌将允许生长促进目标和非目标植物物种一样。在这里，我们利用合成transkingdom信号建立植物宿主特异性控制固氮催化剂固氮酶在固氮根瘤菌caulinodans占领大麦根。这项工作演示了如何建立伙伴特异性的相互作用，以避免潜在的非目标植物的生长促进。在谷物和固氮细菌之间工程化固氮共生体代表了在农业中可持续地提供生物固定氮（N）的有前途的策略。我们以前开发了新的植物和细菌之间的跨界信号，通过植物生产的细菌信号rhizopine，允许控制与植物相关的细菌基因表达。在这里，我们已经开发了一个纯合的根碱生产（RhiP）大麦线和杂交根碱吸收系统，我们的模型细菌Azorhizobium caulinodans ORS571（Ac）的根碱感知的敏感性提高了103倍。使用这种改进的遗传电路，我们建立了固氮酶主调节因子nifA和N代谢因子rpoN的紧密的根碱依赖性转录控制，其通过细菌定殖RhiP大麦根在体外和原位驱动固氮酶表达和活性。虽然在原位固氮酶活性是次优有效的相对于野生型菌株，激活是特定的RhiP大麦和野生型植物的根上没有观察到。这项工作代表了一个关键的里程碑，朝着发展的合成植物控制的共生，其中细菌固定N2只有当与所需的宿主植物接触，并防止与非目标植物物种的相互作用。
Inoculation of cereals with diazotrophic (N2-fixing) bacteria offers a sustainable alternative to the application of nitrogen fertilizers in agriculture. While natural diazotrophs have evolved multilayered regulatory mechanisms that couple N2 fixation with assimilation of the product NH3 and prevent release to plants, genetic modifications can permit excess production and excretion of NH3. However, a lack of stringent host-specificity for root colonization by the bacteria would allow growth promotion of target and nontarget plants species alike. Here, we exploit synthetic transkingdom signaling to establish plant host-specific control of the N2-fixation catalyst nitrogenase in Azorhizobium caulinodans occupying barley roots. This work demonstrates how partner-specific interactions can be established to avoid potential growth promotion of nontarget plants. Engineering N2-fixing symbioses between cereals and diazotrophic bacteria represents a promising strategy to sustainably deliver biologically fixed nitrogen (N) in agriculture. We previously developed novel transkingdom signaling between plants and bacteria, through plant production of the bacterial signal rhizopine, allowing control of bacterial gene expression in association with the plant. Here, we have developed both a homozygous rhizopine producing (RhiP) barley line and a hybrid rhizopine uptake system that conveys upon our model bacterium Azorhizobium caulinodans ORS571 (Ac) 103-fold improved sensitivity for rhizopine perception. Using this improved genetic circuitry, we established tight rhizopine-dependent transcriptional control of the nitrogenase master regulator nifA and the N metabolism σ-factor rpoN, which drove nitrogenase expression and activity in vitro and in situ by bacteria colonizing RhiP barley roots. Although in situ nitrogenase activity was suboptimally effective relative to the wild-type strain, activation was specific to RhiP barley and was not observed on the roots of wild-type plants. This work represents a key milestone toward the development of a synthetic plant-controlled symbiosis in which the bacteria fix N2 only when in contact with the desired host plant and are prevented from interaction with nontarget plant species.
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影响因子：
3.3
作者：
Knights HE;Jorrin B;Haskett TL;Poole PS
通讯作者：
Poole PS
影响因子：
5.2
作者：
Haskett TL;Knights HE;Jorrin B;Mendes MD;Poole PS
通讯作者：
Poole PS
影响因子：
4.2
作者：
Diaz-Zorita, Martin;Virginia Fernandez-Canigia, Maria
通讯作者：
Virginia Fernandez-Canigia, Maria
影响因子：
3.2
作者：
Karunakaran, R.;Ramachandran, V. K.;Poole, P. S.
通讯作者：
Poole, P. S.
影响因子：
4.9
作者：
Colnaghi, R;Green, A;Kennedy, C
通讯作者：
Kennedy, C