Engineered plant microbiome could reduce the need for pesticides

‘For the first time we have been able to change the makeup of a plant’s microbiome in a targeted way.’

The importance of the microbiome, particularly in the gut of humans, and its role in maintaining overall health is well established. Now an international group of researchers say that they have, for the first time, engineered the microbiome of plants to boost the presence of ‘good’ bacteria that protect the plant from disease.

The past decade has seen intensive research into plant microbiomes to understand how they impact a plant’s health and its vulnerability to disease. Publishing their work in Nature Communications, researchers from the University of Southampton, in collaboration with researchers from Austria and China, say that their breakthrough could reduce reliance on pesticides.

‘For the first time we have been able to change the makeup of a plant’s microbiome in a targeted way, boosting the numbers of beneficial bacteria that can protect the plant from other, harmful bacteria,’ said Dr Tomislav Cernava, co-author of the paper and Associate Professor in Plant-Microbiome Interactions at the University of Southampton.

Working with rice, the researchers found that one specific gene found in the lignin biosynthesis cluster of the rice plant is involved in shaping its microbiome. It was observed that when this gene was deactivated, there was a decrease in the population of certain beneficial bacteria, confirming its importance in the makeup of the microbiome community. Researchers then over-expressed the gene, which led to an increase in the proportion of beneficial bacteria.

These engineered rice plants were then exposed to a pathogen that causes bacterial blight in rice crops, and they were found to be ‘substantially more resistant [to the blight] than wild-type rice.’ Blight can lead to significant loss of rice crops in Asia and is usually controlled with pesticides.

‘This breakthrough could reduce reliance on pesticides that are harmful to the environment. We’ve achieved this in rice crops, but the framework we’ve created could be applied to other plants and unlock opportunities to improve their microbiome. For example microbes that increase nutrient provision to crops could reduce the need for synthetic fertiliser,’ Cernava added.