“Grape growers in Mexico have a new tool to fight powdery mildew, a common fungal disease, after the country became the first in the world to approve the commercial sale of an RNA-based biofungicide…

Oifirax, developed by the U.S. company GreenLight Biosciences, uses RNA molecules to silence a gene essential for the survival of the disease-causing fungus Erysiphe necator. The Mexican government announced the product’s commercial approval on 12 August, following a 9-month regulatory process involving the country’s health, agricultural, and environmental authorities…

Scientists have spent more than a decade developing products to control pests and diseases using a process called RNA interference. First off the block were pesticides: In 2023 GreenLight released Calantha, which targets the Colorado potato beetle. The spray uses RNA molecules to block a specific gene that encodes a key protein in the beetle. When the larvae eat leaves that have been sprayed, the RNA makes it into their gut, where cellular machinery destroys the matching messenger RNA (mRNA) that contains the instructions for creating the protein, killing the beetle.

The company’s new fungicide works in a similar way. It targets CYP51, a gene conserved among various fungal species that is involved in producing a crucial compound called ergosterol. When sprayed on grapes affected by powdery mildew, it prevents E. necator from producing ergosterol, causing its cell membranes to break down. This prevents the fungus from growing and ultimately leads to its death.

Oifirax has proved effective in eliminating E. necator without harming species such as monarch butterflies, honey bees, and earthworms, GreenLight CEO Andrey Zarur said during the press conference announcing the approval. He said the company submitted a bioinformatics analysis showing Oifirax doesn’t affect other soil organisms or vertebrates, and that Mexico’s regulatory agency will continue to conduct rigorous studies to ensure its safety.”

From Science.