'Vaccinate' plants to fight pests and diseases

Instead of eradicating harmful chemicals, scientists at the University of Queensland (Australia) have found a new and effective method called BioClay - capable of activating a defense mechanism of the plant to fight off the pathogen.

Attack oriented pathogens

Pests threaten crops around the world, greatly affecting food security of many countries. The usual solution used by most farmers is to spray pesticides - essentially chemicals - onto plants to kill pests. This is effective but expensive and especially concerns about the environment. Chemicals can penetrate water supplies, cause toxicity and can cause pathogens to adapt, leading to resistance to pesticides.

A research team at the University of Queensland in Australia is developing a solution to replace chemical pesticides by manipulating BioClay gene expression . According to them, this method is both effective and environmentally sustainable.

According to the study published in the journal Nature Plants in early 2017, BioClay is a non-toxic nano clay containing RNA (type of nucleic acid, a genetic basis at the molecular level) double strand (dsRNA ), can be used to protect plants from specific pathogens.

'When BioClay is sprayed into plants, special dsRNA with each type of pathogen will be released from clay and into the plant. This triggers a plant defense mechanism to counteract that kind of pathogen, " said Neena, a research team member - on Digital Trends. In other words, the plant reacts as if it is being Attack and build defense systems, like the way people create defensive reactions to the body when vaccinated.

Scientists tested BioClay on tobacco leaves and Arabidopsis - a flowering plant in the cruciferous family. As a result, detected dsRNA persists in BioClay in the environment and on leaves 30 days after spraying. During that time, they are absorbed by plant cells to silently destroy the target of pathogens.

The University of Queensland team and BioClay spray equipment.(Photo: Twitter).

In another test, to test the potential of this technology, the team tested BioClay containing dsRNAs designed to counteract two plant viruses - pepper mold virus (PMMoV) and melon mosaic virus. mouse (CMV) on cowpea.

They also use commercial RNA antagonists that are being used on the market to kill insects to compare efficiencies. After 5 days, BioClay gave better results when significantly reducing the specific injury or necrosis of CMV disease.

And yet, in another experiment, tobacco plants were sprayed with BioClay and conventional pesticides and challenged with pathogens for 20 days. As a result, only plants treated with BioClay have high disease resistance. In addition, scientists also found evidence of protection against pathogens in newly hatched young leaves, which appear after several weeks of treatment with BioClay.

No toxic to humans and the environment

According to the research team, even when using pesticides, humans still lose up to 40% of productivity because of pests and diseases. Chemical pesticides kill harmful insects but also affect a number of beneficial insects. Meanwhile, according to the research team, BioClay has a specific goal, only killing the targeted pathogens. Environmentally friendly and human is one of the outstanding advantages of this method.

'Clay in BioClay is fully biodegradable in the presence of water vapor and carbon dioxide. RNA also exists for a short period of time in plants and specifically destroys only the pathogens that we target. Meanwhile, conventional chemical pesticides can poison water, negatively impact human health and kill real insects that are beneficial for plants. The dsRNA is cut into small pieces of RNA by plant enzymes. "These small pieces only attack the pathogen when it infects plants without altering the plant genome," Mitter added.

BioClay's field trials may start in Australia later this year. Mr. Mitter told SciDev.Net that the first test will be conducted for viruses that harm crops such as peppers and tomatoes.

Scientists at the University of Queensland hope BioClay will be commercialized within the next 5 years and the price may be very reasonable.