Control of gene expression in rhizosphere bacteria by plant metabolites

植物代谢物控制根际细菌基因表达

• 批准号: 2270043
• 金额: --
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2270043
• 关键词: Control; gene; expression; rhizosphere; bacteria

With a growing human population expected to reach over 11 billion by 2100, it is vital that agriculture is able to grow correspondingly to sustain this population size. To date, increases in agricultural yield have been supported by reliance on synthetic fertilisers containing nitrogen produced by the HaberBosch process. However, this is neither environmentally nor economically sustainable. In the natural world, biological nitrogen fixation (BNF) is carried out by prokaryotes using the enzyme nitrogenase. A limited group of plants is able to form symbiotic associations with these prokaryotes, allowing them to benefit from BNF. The most well-studied example of this is the symbiosis between legumes and rhizobia. However, staple cereal crops such as wheat are unable to form a similar symbiosis, meaning that these crops are primarily dependent on Haber-Bosch nitrogen. An ongoing challenge in biological research in the 21st century is that of applying BNF to staple cereal crops. This project aims to extend BNF to cereals by linking nitrogen fixation and excretion in plant growth-promoting rhizobacteria (PGPRs) to a natural plant signal. Bacterial regulatory systems that respond to cereal root exudates will be identified using RNA sequencing, qRT-PCR and lux promoter fusions, and these root exudates characterised using mass spectrometry. Control circuits will be engineered to link these regulatory systems to genes encoding products involved in nitrogen fixation; in particular, the regulatory gene nifA. This will result in the formation of engineered bacterial strains that fix and excrete nitrogen in cereal rhizospheres.

随着不断增长的人口预计到2100年将超过110亿，农业能够相应地增长以维持这一人口规模至关重要。到目前为止，农业产量的增加得益于对HaberBosch工艺生产的含氮合成化肥的依赖。然而，这在环境和经济上都是不可持续的。在自然界中，生物固氮是由原核生物利用固氮酶进行的。一组有限的植物能够与这些原核生物形成共生关系，使它们能够从生物固氮中受益。这方面研究最充分的例子是豆类和根瘤菌之间的共生。然而，小麦等主要谷类作物无法形成类似的共生关系，这意味着这些作物主要依赖Haber-Bosch氮。21世纪生物学研究中的一个持续挑战是将生物固氮应用于主要粮食作物。该项目旨在通过将植物生长促进根际细菌(PGPR)的固氮和排泄与天然植物信号联系起来，将生物固氮扩展到谷物中。对谷类根分泌物作出反应的细菌调节系统将通过RNA测序、qRT-PCR和lux启动子融合进行鉴定，并使用质谱仪对这些根分泌物进行表征。控制电路将被设计成将这些调控系统与编码与固氮有关的产物的基因联系起来，特别是调控基因NifA。这将导致在谷物根际形成固定和排泄氮的工程细菌菌株。