Food Security Theme: Crop-microbe associations

Developments arising from research in the soil microbiome demonstrate how microbiology can contribute to achieving sustainable food production. Nitrogen is an important nutrient for plant growth, but the majority exists as atmospheric gas which is unavailable to plants. To address this, intensive agriculture practices rely on synthetic nitrogen fertilisers to increase crop yields. However, the anthropogenic production of reactive nitrogen has resulted in large shifts in the global nitrogen cycle with environmental costs. For example, excessive use of synthetic fertilisers can cause reactive nitrogen to leach into water systems and the air, resulting in environmental damage (groundwater contamination, eutrophication, release of greenhouse gases) and consequences for human health.

Biological nitrogen fixation is carried out by soil micro-organisms associated with plant roots which convert atmospheric nitrogen into reactive nitrogen available to plants. This occurs naturally in leguminous plants (such as beans and peas) via symbiotic bacteria associated with their roots. Increased global production of leguminous plants can contribute to global food security and they are a plant-based source of protein with numerous health benefits. However, much of the world depends on cereal-based crops. Symbioses can be engineered in non-leguminous crops to increase nitrogen availability in soil and thereby increase crop yields and reduce the use of synthetic fertilisers. In addition, intercropping systems can be adopted in which cereal crops are rotated with legume crops.

The UN General Assembly declared 2016 the International Year of Pulses to highlight the benefits of pulses in sustainable food production. Nitrogen use efficiency (NUE) has been proposed as an indicator for the SDGs by the EU Expert Nitrogen Panel.  After Brexit (and any transition phase) UK agriculture will be operating outside of the EU’s Common Agricultural Policy (CAP) which means that a new domestic agriculture policy is needed. 

The Microbiology Society has been active in the area of food security. Agriculture and food was identified as a key area of microbiome research in the 2017 “Unlocking the Microbiome” report and associated workshops. In 2015, the Society published a briefing on food security from the soil microbiome and a position statement on food security and safety in 2011. This statement highlighted the concern that the role of microbiology in addressing food security and safety was poorly understood and under-represented and identified 9 themes for research one of which was soil health and nutrient cycling.


Further reading


Agronomist & Arable Farmer. BEPA’s House of Commons pulse promotion tops off International Year of Pulses campaign; 2016. [accessed 12 March 2019].

Considine MJ, Siddique KHM, Foyer CH. Nature’s pulse power: legumes, food security and climate change. 2017;68:1815–1818.

Fowler D, Coyle M, Skiba U, Sutton MA, Cape JN et al. The global nitrogen cycle in the twenty-first century. 2013;368:1621.

Microbiology Society. Food Security from the soil microbiome; 2015.  [access 13 march 2019].

ResearchGate. Nitrogen Use Efficiency (NUE) – an indicator for the utilization of nitrogen in agriculture and food systems prepared by the EY Nitrogen Expert Panel; 2015. [accessed 12 March 2019].

Stagnari F, Maggio A, Galieni A, Pisante M. Multiple benefits of legumes for agriculture sustainability: an overview. 2017;4:2.

Synthetic Symbioses. About SynSym; 2018. [accessed 12 March 2019].