CCMB Researchers Identify Key Antiviral Defense System in Plants
HYDERABAD — Researchers at the CSIR-Centre for Cellular and Molecular Biology have identified a key defense system plants use to fight viruses.
Plants are known to use liquid-like, sticky protein droplets to trap and disable invading viruses. The study, led by Mandar V. Deshmukh and published in the Journal of the American Chemical Society, maps the molecular-level mechanism behind the process.
Many viruses carry double-stranded RNA as their genetic material. When plants are infected, they produce more of certain RNA-binding proteins that can identify viral RNA. Some of these proteins bind to the virus’s genetic machinery at sites called viral replication complexes and stall the machinery from dividing. Without the ability to divide its genetic material, the virus cannot replicate in infected cells.
However, the details of how the proteins bind to RNA had remained unclear, according to a CCMB release.
RNA-binding proteins were traditionally thought to attach to double-stranded RNA in a simple lock-and-key manner. But using advanced techniques including nuclear magnetic resonance spectroscopy, fluorescence microscopy and molecular dynamics simulations, the CCMB team found a more complex mechanism.
The researchers discovered a unique fold in double-stranded RNA-binding proteins. In this fold, electric charges are distributed across the protein surface in a way that creates sticky patches. Positive electric charges attract negative charges, drawing the proteins together and allowing them to bind to one another. The resulting interconnected mesh of proteins forms dense, gel-like droplets.
“These proteins act like a molecular glue,” said Jaydeep Paul, first author of the study. “By forming these dense, gel-like droplets, the plant cells effectively trap the viral RNA, preventing it from interacting with the machinery needed for replication.”
The droplets, also known as biomolecular condensates, reflect a shift in how scientists understand living cells.
“Rather than a collection of static membrane-bound compartments like the nucleus and mitochondria, the cell is now seen as a dynamic environment in which membraneless organelles form like oil droplets in water. Understanding these states has significant implications for both basic science as well as translations in agricultural and medical biotechnology,” Deshmukh said.
For agriculture, the discovery could open new paths to developing crop varieties with stronger natural immunity. By mimicking or strengthening these protein-based traps, scientists may be able to design plants that are more resilient to viral outbreaks that cause billions of dollars in crop losses worldwide.
The study could also have implications for human health. In human cells, the findings may help researchers explore ways to manipulate sticky protein patches to dissolve neurotoxic clumps associated with dementia or dismantle liquid barriers that protect growing tumors.
A better understanding of these molecular mechanisms could also help scientists design drugs that precisely target and manipulate sticky protein patches, according to the release. (Source: IANS)
