Scientists from University of California-Riverside, have made a significant breakthrough in understanding how plants prevent viruses from passing to their seeds. This discovery could have profound implications for agriculture, leading to healthier crops and significantly reducing disease spread from mothers to children.
The ability of plant viruses to travel worldwide through seeds and remain dormant for years poses a significant challenge in farming, which this research could help mitigate.
Only 0-5% of the seedlings usually get infected when a virus-infected mother plant produces seeds. Scientists wanted to understand how the mother plant prevents the virus from spreading to most of its offspring.
A UCR-led team found the immune system pathway that stops this transmission. They tested many Arabidopsis plants that were infected with a virus. They studied which genes make the plants and their seeds more resistant.
Two essential genes are crucial in stopping viruses from reaching seeds, and they work during early seed development. These genes are part of the RNA interference pathway, which uses small RNA fragments to block virus proteins from forming. This helps prevent seed infections as the seeds develop in the mother plant.
Scientists created mutant plants by removing two essential genes that produce necessary enzymes. Without these enzymes, the plants couldn’t make small RNA fragments to fight off viruses. These mutant plants grew and produced seeds typically.
However, when infected with a virus, they showed severe symptoms, produced fewer seeds, and had a much higher virus transmission rate to new seedlings—up to 40% were infected.
Scientists were thrilled to see a significant change in virus transmission when they removed an immune pathway. They then discovered that viruses can still infect a small number of seeds because the virus makes a protein that blocks the plant’s immune response. Now, they’re finding ways to boost this immune response to reduce the spread of viruses in seeds even more.
The pathway they discovered is found in many organisms, which could help prevent diseases in animals and humans.
Scientists are especially interested in using this knowledge to reduce Zika virus transmission from mother to baby, as Zika can cause severe congenital disabilities. They hope to develop new drugs that block Zika’s proteins, interfering with the immune response.
Journal reference :
- Si Liu ∙ Shou-Wei Ding. Antiviral RNA interference inhibits virus vertical transmission in plants. Cell Host & Microbe. DOI: 10.1016/j.chom.2024.08.009.