Helping to promote the natural relationship between plants and bacteria could reduce reliance on environmentally damaging fertilisers, a study has found.

As the population grows and crop yields are threatened by climate change, scientists are keen to help promote plant growth in a natural and sustainable way.

Today, published in Microbiome, researchers including those at the Universities of Warwick and Justus Liebig (Germany) have shown a new way to boost plant nutrient uptake and growth. This could reduce the need for fertilisers, an input to agriculture which can be harmful for the environment. Fertilisers can run into waterways, or get broken down by microbes in the soil, releasing the potent greenhouse gas nitrous oxide into the atmosphere.

The team of researchers investigated the efficiency of plant-bacteria relationships (also known as symbiosis or nodulation) – while also shedding light on how this natural phenomenon impacts interactions with other microbes in the soil.

Legumes (peas and beans) interact with symbiotic bacteria (known as rhizobia) that ‘fix’ nitrogen from the air and provide it as nutrients to the plant. These microbes harness potential to help plants acquire soil nutrients to boost growth or develop stress resilience. These properties make legume crops relatively independent of the application of chemical fertilisers and offer an agriculturally sustainable approach to food production. Legumes can interact with many species of rhizobia, but the outcome of this interaction depends on the bacteria’s ability to fix nitrogen and the soil type – the ‘symbiotic efficiency’.

In the study, funded by the Biotechnology and Biological Sciences Research Council (BBSRC), the scientists identified the impact of different symbiotic efficiency on shaping not only plant growth and nutrition, but on the other microbes in the soil, which could help boost plant and soil health as ‘biofertilisers’. The work was carried out using a relative of peas and beans which can interact with different types of nitrogen-fixing bacteria, on a range of soil types representative of agricultural environments – including at the University of Warwick’s Innovation Campus, Stratford-Upon-Avon.

Using different bacteria strains, the team measured the plant’s molecular responses and the amount of minerals in the plant. The bacterial and fungal communities were also recorded in different locations: in the soil, around the root and inside the root. By combining all of these types and locations of data, an understanding of the impact of ‘symbiotic efficiency’ was established.

Professor Patrick Schäfer, Justus Liebig University, Gießen, Germany, said: “Plant growth and fitness greatly depend on symbiosis with a highly complex community of microorganisms (the ‘microbiome’), on the surface of roots. Our study showed that the nutrient status of soil affected the symbiosis between beneficial rhizobia – which fix atmospheric nitrogen in exchange for nutrients with legumes.”

Co-Author of the study, Dr Beatriz Lagunas, School of Life Sciences, University of Warwick, said: “Our work demonstrated that symbiosis with different bacteria species can change the whole root microbiome. We uncovered the ability of nitrogen-fixing bacteria to install a plant-beneficial microbiome depending on their environment. We also identified microbial strains as part of this community which could be useful beneficial friendly-fertilisers for the future.”

Professor Miriam Gifford, School of Life Sciences, University of Warwick, added: “This work has significant implications for the application of such nitrogen-fixing bacteria to secure the production of important food legumes such as beans and peas in the field.

“After this work, we are now testing the impact of microbes on different plant species to evaluate plant growth and stress resilience. We aim to collaborate with agricultural companies to evaluate the use of these microbes as biofertilisers for legume production. This should contribute to decreasing the use of chemical fertilisers reducing the impact of these on the environment.”

Read the study here https://microbiomejournal.biomedcentral.com/articles/10.1186/s40168-023-01592-0

Notes to editors

Media contacts

University of Warwick press office contact: 

Annie Slinn

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Email: annie.slinn@warwick.ac.uk

Innovation Campus Stratford-upon-Avon

The Innovation Campus Stratford-upon-Avon has a focus on academic research in agri-tech and life sciences; crop science; digital technologies and future mobility and advanced manufacturing. It is home to applied research groups from the School of Life Sciences and WMG, as well as several cutting-edge and high-growth businesses including the Lotus Advanced Technology Centre, Corteva Agriscience, Rimac Technology R&D and Lyra Electronics. The mix of academia and industry working together on the exchange of ideas and knowledge helps contribute to the economic, social, and cultural growth of the Warwickshire region.

The Warwick Crop Centre is based on the campus, where plant scientists, epidemiologists, geneticists and entomologists work with industry to solve sector specific problems for farmers and growers. There is a dedicated research farm running field trials and pest monitoring projects and the UK Vegetable Gene Bank, a Defra funded facility which holds a national collection of seeds for wild relatives and heritage varieties of commonly gown field vegetables.

More about the campus https://warwick.ac.uk/about/strategy/innovation/innovation-campus/

3 July 2023