While classical breeding traits have focussed on above‐ground tissues, it is becoming clear that underground aspects of plant life are a hidden treasure of tools applicable for resilient crop production. Plants of the legume family develop specialized organs, called nodules, which serve as hosts for Rhizobium bacteroids. A highly specialized symbiotic relationship exists deep inside the nodules. In exchange for carbohydrates, host‐specific rhizobia bacteroids can assimilate nitrogen from the air and fix it into a form that can be used by plants in a process known as biological nitrogen fixation. While we understand certain aspects of how this inter‐species relationship is established, the exact biochemistry of this exchange remains dogmatic. In their recent work, Christen and colleagues (Flores‐Tinoco et al , 2020) challenge the current model of nitrogen exchange and argue that that an expanded model is needed to fit experimental findings related to nitrogen fixation. The authors perform an elegant set of experiments and highlight that rather than a single‐way flow of nitrogen, the N‐fixing process is in fact an elaborate metabolic exchange between the nodule‐dwelling bacteroids and the host plant. Importantly, this work provides an updated theoretical framework with the “catchy” name CATCH‐N which delivers up to 25% higher yields of nitrogen than classical models and is suitable for rational bioengineering and optimization of nitrogen fixation in microorganisms.

中文翻译：

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如何捕获氮-用正确的化学物质进行种间交换。

尽管经典育种特征集中在地上组织上，但很明显，植物生命的地下方面是适用于有弹性作物生产的工具的隐藏宝藏。豆科家族的植物发育称为根瘤的特殊器官，它们是根瘤菌类细菌的宿主。结节内部深深存在着高度专业化的共生关系。作为碳水化合物的交换，宿主特有的根瘤菌类细菌可以吸收空气中的氮并将其固定为植物可以在称为生物固氮的过程中使用的形式。尽管我们了解种间关系如何建立的某些方面，但这种交换的确切生物化学仍然是教条式的。Christen及其同事在最近的工作中（Flores-Tinoco等人，2020）挑战了当前的氮交换模型，并认为需要扩展模型来拟合与固氮有关的实验结果。作者进行了一系列优雅的实验，并强调，固氮过程不是单向流动的氮气，而是根瘤寄居类细菌与寄主植物之间复杂的代谢交换。重要的是，这项工作提供了一个具有“醒目”名称CATCH-N的更新的理论框架，与经典模型相比，它的氮产量提高了25％，适用于合理的生物工程和微生物中氮固定的优化。