Engineering nitrogen fixation

Workpackage I: N2 Fixation

During the Green Revolution nitrogen fertilisers as much as tripled cereal yields in some areas. However, these synthetic fertilisers remain unaffordable in developing countries, for example for smallholder farmers in sub-Saharan Africa whose yields are 15% to 20% of their potential. As part of the ENSA project (Engineering Nitrogen Symbiosis for Africa), Professor Giles Oldroyd’s group at the John Innes Centre is taking a synthetic biology approach to engineer nitrogen-fixation into cereals. Legumes are able to form symbiotic interactions with nitrogen-fixing rhizobial bacteria through formation of root nodules. Engineering this complex interaction into cereals is highly ambitious and could not be tackled without the tools of synthetic biology. The potential impact on yields in sub-Saharan Africa without reliance on chemical fertilisers is huge. 

Simple systems for engineering symbiosis

OpenPlant supports an effort to establish Marchantia as a model system for signalling in symbiosis. Marchantia provides a potentially ground-breaking advance for testing and engineering symbiotic signalling. The Oldroyd and Schornack laboratories are exploring the domestication of new liverwort-fungi associations.  New laboratory co-cultivation and marker techniques are being developed to study symbiotic interactions between Marchantia spp. and Glomermycota fungi. Access to simpler symbioses opens new approaches to engineering the precise signalling mechanisms that underpin mutualism.  

Marchantia species and close relatives have been screened for their ability to form arbuscular mycorrhizal symbiosis.  The Oldroyd lab has produced a draft of the 250Mb genome of Marchantia paleacea. In addition, high throughput methods have been developed for transformation of M. paleacea. We have developed techniques for routine production of Cas9-CRISPR mediated knockout lines in different Marchantia species.

DNA parts and synthetic circuits

OpenPlant is supporting the assembly of a toolkit of standardised DNA parts for transcription factors and signalling components. These include LysM receptor-like kinases and novel cell reporters for high resolution cellular imaging. The DNA parts are compatible with the Phytobrick standard and Loop Assembly method. The toolkit  will allow construction of new circuits for engineering synthetic responses to Nod factors, and rapid prototyping of synthetic circuits in transgenic Marchantia plants.