A VACCINE FOR PLANTS
Just as humans can catch a cold, plants can also get viral infections. It generally starts with an insect bite. The virus only needs to reach a single cell to hijack its machinery and begin replication. Progeny viruses are released to neighbouring cells, and the infection spreads. Soon, the virus gets to the plant’s vascular system and quickly spreads to the rest of the plant.
Plants also have an immune system. When a virus infects a plant cell, it often releases RNA in the form of MRNA or doublestranded RNA to replicate. The plant immune system recognises the viral RNA and activates enzymes that chop and neutralise it to avoid the spread of the disease. Infected cells can send a signal to neighbouring cells activating antiviral defences even before the virus’ arrival.
The tactic is deadly for the virus, but not always efficient.
Viruses are part of the pest and pathogen burden that reduces global food production by 20% to 40%. With a growing global food demand and the effect of climate change on crops, new, more effective virus control is needed.
The use of insecticides, pesticides and genetic modification are the currently available methods to protect plants from viral infections.
But these methods have significant drawbacks.
Insecticides and pesticides are broadspectrum, which means they can damage the target pests and other flora and non-pest insects, while genetic modification has significant issues surrounding acceptance and regulation.
Researchers at the University of Queensland have found a way to stimulate the plant’s immune system to mount a defence against potential viruses.
Their technology, called Bioclay, works very much like a vaccine. The scientists take the RNA sequence from the pathogen, load it on a clay nanomaterial and spray it on crops.
The virus RNA slowly releases on the surface of the leaves. It enters the plant and primes the immune system to recognise the invader without causing the infection.
The clay sequentially degrades in the presence of natural carbon dioxide and moisture.
Various research groups worldwide are working on RNA vaccines for plants. These vaccines represent a much simpler and faster technique than genetically engineering a plant for viral resistance and allow scientists and farmers to keep up with the quick evolution of viral pathogens.