Enhancing Crop Performance using Soil Microbes

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The Microbiology Society is undertaking a project entitled A Sustainable Future as part of our 75th Anniversary, which aims to highlight the Sustainable Development Goals (SDGs) to our members and empower them to use their research to evidence and impact the goals. Earlier this year, we put a call out to our members to submit case studies in the following three areas: antimicrobial resistance, soil health and the circular economy.

This case study is written by Dr Ewen Mullins, who is Head of the Crop Science department at the Agriculture and Food Development Authority (TEAGASC). It focuses on Soil Health; maintaining the health of our soils has gained increasing prominence in recent years. Soils are essential for the global food system and regulate water, carbon and nitrogen cycles but are put under pressure from population growth and climate change.

What are the challenges that this research addresses?

Fungal diseases cause huge yield losses in agriculture every year. The most well-known fungal disease is late blight, which was the cause of the  potato famine in 1845, during which over one million people starved to death in Ireland. The disease, caused by a fungus-like mould called Phytophthora infestans, still causes major losses in global food production, costing the €7 billion EU potato industry over €1 billion in chemical usage and yield losses each year.

The current method for P. infestans control is fungicides, which are expensive. In order to manage the disease, farmers must use multiple applications of chemical fungicides on their crops throughout the growth season, with applications exceeding 10 per year.

What findings and solutions were provided by this research?

Researchers at The Agriculture and Food Development Authority (TEAGASC) have identified a novel bacterium, which can modify plant characteristics and provide beneficial traits, such as resistance to diseases.

This is not the first time scientists have used bacteria to genetically modify plants. Agrobacterium tumefaciens, sometimes referred to as ‘the world’s plant engineer’, has been genetically transforming plants for millennia, and has been harnessed for many years to generate genetically modified crops around the world. Over 180 million hectares of crops that have been modified using Agrobacterium are grown around the world each year. However, there are limitations to using Agrobacterium to modify crops, including patents and technical challenges. In an effort to overcome this, researchers started to hunt for alternative microbes, which may have the same effect.  

Dr Ewen Mullins, Head of Crop Science at TEAGASC, and colleagues found an alternative to Agrobacterium, which may even be able to modify a wider range of crops more effectively. This alternative bacterium, called Ensifer adherens, is collected from the rhizosphere – the diverse microbial community that lives in the soil around plant roots.

Ensifer adherens can be used to change the genetic material of the plant by a process called Ensifer-mediated transformation (EMT), whereby the plant genome is engineered by the bacteria, and characteristics are modified. The team have already demonstrated the potential of EMT to generate potato varieties with late blight resistance.

How can this research support the transition to a more sustainable future?

It is hoped that introducing novel genetic resistance such as this to crops, will reduce the need for fungicides in agriculture. This will decrease the cost of fungal control for farmers and will also prevent the destruction of beneficial soil fungi. Reduction of fungicides, pesticides and artificial fertiliser is vital in the shift to a more sustainable farming system, and novel methods such as EMT are crucial for feeding the growing population in a sustainable manner, and achieving Sustainable Development Goal 2: Zero Hunger.

What is the future for research and innovation in this area?

Dr Mullins predicts there are many more bacteria in the rhizosphere which may be able to modify plants in the same way as Ensifer and Agrobacterium, and may even be able to transform a wider range of crops. Most importantly, crop-specific rhizobia can be identified with the capacity to support crop productivity further, against the wide range of challenges currently facing food production systems. Learn more about this research in our press release.

About the Author

Dr Ewen Mullins is Head of the Crop Science department at the Agriculture and Food Development Authority (TEAGASC). More information about his work is available here.