Characterisation of oxygen regulation mechanisms in Rhizobium leguminosarum for repurposing as tools in the engineering of nitrogen fixation

氮素是植物生长的关键养分，氮肥的使用大大提高了作物的生产力。然而，这些肥料也造成了严重的环境破坏，对许多发展中国家来说负担不起。相反，许多植物物种通过与固氮根瘤菌形成共生关系来获得氮。它们进入植物的根部，在那里它们转化为高度专业化的准细胞器，为植物提供从大气中固定的氮，以换取养分和庇护所。氧是调节这种转化的关键信号，因为它对执行固氮的固氮酶是有毒的。两种细菌蛋白质，NifA和FnrN，被认为是调节和激活固氮的关键。我们的目标是研究这些基因是如何在转录和蛋白质水平上被调控的，并确定发生这种情况的机制。我们的下一个目标是利用我们对这些机制的理解来开发合成生物学工具，这些工具可以用于将这种共生引入其他植物和细菌。实现这一点可以减少对污染氮肥的需求，并提供一种可持续的方式来提高作物产量。BBSRC的优先领域：粮食、营养和健康可持续提高农业生产综合生物学环境和土地利用全球粮食安全AFS，ENWW

Nitrogen is a key nutrient for plant growth and the use of nitrogen fertilizers has resulted in significant boosts in crop productivity. However, these fertilizers also cause significantenvironmental damage and are unaffordable for much of the developing world. Many plant species instead acquire their nitrogen by forming a symbiotic relationship with nitrogen fixingRhizobium bacteria. These enter into the plant's roots where they transform into highly specialized quasi-organelles, providing the plant with nitrogen fixed from the atmosphere inexchange for nutrients and shelter. Oxygen is a key signal in the regulation of this transformation because it is toxic to the nitrogenase enzyme that performs nitrogen fixation.Two bacterial proteins, NifA and FnrN, are known to be critical for the regulation and activation of nitrogen fixation. We aim to study how these are regulated at the transcriptional and proteinlevel and to determine the mechanisms by which this occurs. We next aim to use our understanding of these mechanisms to develop synthetic biology tools which can be used inefforts to introduce this symbiosis into other plants and bacteria. Achieving this could reduce the need for polluting nitrogen fertilizers and provide a sustainable way to boost crop yields.BBSRC priority areas addressed:Food, Nutrition and HealthSustainably enhancing agricultural productionSynthetic biologyEnvironment and Land UseGlobal Food SecurityAFS, ENWW