Australian researchers from the University of Queensland have successfully used a gene-silencing spray, named BioClay, a combination of biomolecules and clay, to protect tobacco plants from a virus for 20 days with a single application. Their study has been published in Nature Plants.
“When BioClay is sprayed onto a plant, the virus-specific dsRNA (stranded ribonucleic acid) is slowly released from the clay nanosheets into the plant. This activates a pathway in the plant that is a natural defence mechanism. The dsRNA is chopped up into small bits of RNA by enzymes of this pathway. These small bits attack the virus when it infects the plant without altering the plant genome,” explains lead researcher, Neena Mitter, in an interview with SciDev in January in Sydney/Australia.
“Even with current pesticides, we lose up to 40 per cent of our crop productivity because of pests and pathogens. We are hoping that having BioClay in the mix as an environmentally friendly, sustainable crop protection measure will reduce crop losses,” Mitter adds.
While chemical-based pesticides kill the targeted insect, they can also affect a range of other insects that are beneficial, explains the scientists, and adds that BioClay is specific and it only kills the pathogen being targeted. Currently, farmers use insecticides to kill the vector that comes with the viruses, but with BioClay we can target the virus itself, she believes.
BioClay field trials may begin in Australia by year-end. The first test is intended to be on a virus that infects vegetable crops — capsicum, tomato, chilli.
Farmers can use the existing equipment to deliver BioClay and the researchers are hopeful that it will be a commercially viable product for farmers everywhere. The clay component is cheap to make, but not the RNA, Mitter explains to SciDev.