Giving plants ‘good’ bacteria could help them fight bugs and diseases and cut the need for pesticides

Date:06-03-2020

By JONATHAN CHADWICK

- Scientists say beneficial bacteria in soil could support plants’ immune systems
- Approach could help farmers grow fruits year-round and in built-up urban areas
- UK researchers are also working on hydroponics - growing plants without soil

Scientists have developed plant ‘probiotics’ that help fight disease without the use of expensive pesticides.

UK researchers say beneficial bacteria in soil supports plants’ immune systems in a similar way to positive gut bacteria in humans.

By injecting probiotics into a plant’s growth medium, they hope to create ideal growing conditions for herbs, fruits and vegetables while avoiding bugs.

Somewhere between 20 to 40 percent of global crop production are lost to pests, while diseases cost the global economy around $220 billion, according to the UN.

Researchers say plant probiotics will particularly benefit crops grown without soil in enclosed and sterile conditions that are susceptible to disease.

Using tomato plants, the team will now use genetics and biochemistry to gain an understanding of how roots interact with beneficial microbes in soil.

This will be used to develop ‘good bacteria’ for plant growth that fight off pests and diseases thanks to their ‘enhanced’ immune system. 

‘Scientists have learned a lot in recent years about how beneficial bacteria in our guts keep use healthy – and we believe the same is true for plants,’ said Professor Duncan Cameron, director of the Institute for Sustainable Food at the University of Sheffield.

‘By investigating how tomato plants interact with good bacteria in the soil through their roots, we hope to be able to develop plant probiotics to boost their immune systems and help them fight diseases without the need for harmful pesticides.

‘Coupled with synthetic foam soils, this completely new approach could help farmers to grow healthy and sustainable fruits and vegetables out of season and in the urban areas where most people live.’

Today, fruits and vegetables are grown without soil in vast greenhouses and plastic covered tunnels covering 948 hectares in the UK, allowing produce that used to only be available at certain times of the year, such as strawberries, to grow out of season.

But because the plants are grown in sterile conditions, any diseases that get inside these growth chambers can devastate crops.

With concern about the impacts of pesticides on human health and the natural world, the University of Sheffield is hoping to find a chemical-free solution.

By introducing beneficial bacteria in these greenhouse environments, scientists say can prevent these outbreaks, improve productivity and avoid food waste. 

Plant versions of pro-biotic drinks are now being investigated as part of a £1.5 million project at the university, which specialises in hydroponics – plants grown without soil.

In normal agricultural processes, soil supports a plant’s roots, but in a hydroponics system plants are supported artificially and suspended away from the ground.

As part of the hydroponics efforts, scientists have already developed foam ‘soils’ that grow up to 10 times more produce than normal soil because they don’t suffer from soil degradation.

The research could help grow produce in urban areas that don’t have an abundance of soil, relieving the massive demand on agricultural land.

Specially developed foams could help avert a global food security crisis by replacing fast-degrading soils, according to scientists

Professor Cameron said investigations into beneficial bacteria to plants starts with synthetic soils and could eventually be applied to real soil.

'What we’re trying to do is to isolate the good bacteria from soils that naturally suppress disease and grow them in our synthetic soil to understand how they do it in a simpler system than actual soil, our synthetic soil,' he told MailOnline.

'This is immediately applicable in hydroponics so UK growers should be able to quickly adopt the technology, reducing their costs and removing the need for pesticides.

'Once we understand how it works and the conditions that are needed to make it work in our synthetic soul then we’ve got a shot at applying the idea beyond just hydroponics and into real soil.'   

Experts from Sheffield’s Institute for Sustainable Food revealed last week that crops planted in polyurethane foams at an urban farm grow two to 10 times faster than plants grown in soil.

Scientists say their fake soil, which chemically, physically and biologically resembles the real thing, can grow everything from salad to tomatoes.

The system has already been demonstrated by the university using used mattresses at a refugee camp in Jordan, which have nutrients and water pumped into them.

Hydroponics helps feeds residents of dense, concreted areas of vast cities with very little of the required land to feed a growing population.

Professor Duncan Cameron (left) at Sheffield's Department of Animal and Plant Sciences inspecting mattresses, which are being used to grow plants

But even in areas where there is soil, the world is facing a growing soil fertility crisis – a loss of soil that is fertile enough to support plant growth.

Every year 24 billion tons of fertile soil are lost globally to erosion, according to a UN report.

‘The world is facing a crisis of soil fertility,’ said Professor Cameron. ‘If we’re going to fix this, we need to do something radically different.

‘Urban farms that use foam instead of soil could take a lot of pressure off existing agricultural system, and because this system is so efficient, it enables us to feed our growing population using fewer resources.

‘In the future, I hope we can see farms like this all over the world, optimised for local conditions and producing cheap, healthy and sustainable food.’