Scientists have created a spray that protects plants from disease without changing their DNA in a “game-changing” technique hailed as an environmentally-friendly alternative to genetically modified crops and chemical pesticides.

The “gene-silencing” technique of BioClay spray is a breakthrough by researchers at the University of Queensland, Australia, and the University of Surrey, UK, in the field of crop protection. 

The non-toxic spray is based on nanotechnology and aims to overcome the threat that pests and disease pose to plants. It could have huge benefits for agriculture as plant pests and pathogens are estimated to reduce global crop yields by 30 to 40 per cent a year.

At the same time, the need for higher production, regulatory demands, pesticide resistance, and concern about global warming driving the spread of disease all mean there is a growing need for new approaches to crop protection.

The findings show that by combining clay nanoparticles with designer ‘RNAs’ (molecules with essential roles in gene biology), it is possible to silence certain genes within plants. 

The latest research overcomes the instability of ‘naked’ RNAs sprayed on plants, which has previously prevented them from being used effectively for virus protection. By loading the agents on to clay nanoparticles, they do not wash off, enabling them to be released over an extended period of time before degrading.

BioClay spray gives plants virus protection for at least 20 days following a single application and when used a plant behaves as if it were being attacked by a disease or pest and responds by protecting itself.

The BioClay technology, which is based on nanoparticles used in the development of human drug treatments, has a number of advantages over existing chemical-based pesticides. Since BioClay is non-toxic and degradable, there is less risk to the environment and human health. It can also be used in a highly targeted way to protect crops against specific pathogens.

“This is one of the best examples of nanoparticles being effective for biological molecular delivery with a controlled release rate for combating diseases in plants or animals,” says Professor G.Q. Max Lu, president and vice-chancellor of the University of Surrey and co-author of the research paper.

“The same nanoparticle technology invented and patented in my laboratory at the University of Queensland was used for effective targeted drug delivery. It was licensed to an Oxford-based pharmaceutical company and is now being commercialized for drug development.”

“I am very pleased to see the exciting results of this project and the publication of our research in the prestigious Nature Plants journal.”