RNA-based antiviral offers strong defence against deadly agri virus Premium

Scientists develop RNA-based technology to combat plant viruses, enhancing crop immunity and reducing losses worldwide.

Every year, farmers battle an invisible, relentless, formidable enemy: plant viruses. Unlike bacteria or fungi, which can be controlled with pesticides or fungicides, there is no straightforward way to cure crops of viral infections. According to the U.N. Food and Agriculture Organisation (FAO), plant pests and diseases destroy nearly 40% of the world’s annual crop, costing the world more than $220 billion. Of that, plant viruses alone contribute to over $30 billion in losses each year.

In response, scientists started tapping the power of RNA-based technology to help plants defend themselves better — just the way our immune system fights off viruses. At Martin Luther University Halle-Wittenberg in Germany, a team of researchers recently reported developing an RNA-based antiviral agent that confers strong protection against cucumber mosaic virus (CMV), a widespread and destructive plant virus.

CMV infects more than 1,200 plant species, including critical food crops like cucumbers, squash, and cereals, and medicinal plants. It spreads through small sap-sucking insects called aphids. With nearly 90 aphid species capable of transmitting CMV, outbreaks are often difficult to contain.

In India, CMV is responsible for 25-30% yield losses in banana plantations. In pumpkins, cucumbers, and melons, infection rates can soar up to 70%. Affected plants develop a mosaic discoloration, stunted growth, and commercially unviable fruits.

In the new study, the researchers used RNA silencing, a natural defence mechanism found in plants. When a virus infects a plant, it introduces double-stranded RNA (dsRNA), which is a red flag for the plant’s immune system.

The plant responds by activating Dicer-like enzymes (DCLs), which slice the dsRNA into small fragments called small interfering RNAs (siRNAs). These siRNAs then guide the plant’s defence system to recognise and destroy the viral RNA, preventing the infection from spreading.

But this process is far from perfect. Not all siRNA generated by the plant are effective and the virus often mutates rapidly, evading the plant’s natural defences. To strengthen plant immunity, researchers are exploring RNA-based crop protection techniques such as host-induced gene silencing (HIGS) and spray-induced gene silencing (SIGS).