Researchers from Hyderabad have discovered a key mechanism through which plants defend themselves against viral infections.
The plants use sticky, liquid-like protein droplets that trap and disable invading viruses, revealed a study by a team of scientists from the Centre for Cellular and Molecular Biology (CCMB), a CSIR institution.
The study has provided a first-ever molecular-level look at how plants physically disable invading pathogens. The breakthrough, published in the Journal of the American Chemical Society, not only explains how crops survive viral infections but also opens new doors for treating diseases like dementia and cancer in humans.
The research project, led by senior scientist Dr. Mandar V. Deshmukh and his team unravels a dynamic process utilised by plants to protect themselves from viral infections.
The ability to trap viral infections through sticky patches has vast potential in agriculture and medicine. In humans, this mechanism could be used to design drugs that dissolve neurotoxic clumps associated with dementia or dismantle the protective liquid barriers surrounding growing tumors, CCMB researchers said.
Scientists can now also explore designing crop varieties with enhanced natural immunity. By strengthening these protein traps, researchers hope to protect plants from viral outbreaks that currently cause billions of dollars in global crop losses.
By forming these dense droplets, plant cells effectively trap viral RNA and prevent it from interacting with the machinery needed for replication.
These droplets, also known as biomolecular condensates, represent a shift in how scientists understand a living cell. 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 membrane less organelles form like oil droplets in water. Understanding these states has significant implications for both basic science and applications in agricultural and medical biotechnology.”
Traditionally, scientists believed that plant defence proteins acted like a simple ‘lock and key’, latching onto the double-stranded RNA found in many viruses. However, using advanced techniques like Nuclear Magnetic Resonance (NMR) spectroscopy and molecular dynamics simulations, the CCMB team discovered a far more dynamic process.
CCMB researchers identified a unique fold in specific RNA-binding proteins, which creates ‘sticky patches’ of electric charges on the protein’s surface. As positive and negative charges attract, these proteins bind to one another, forming an interconnected mesh.
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The protein mesh creates dense, liquid-like, gel-like droplets known as biomolecular condensates. The droplets act as molecular glue, effectively swarming and trapping the viral RNA, study said.
By encasing the virus’s genetic material at Viral Replication Complexes, the proteins prevent it from interacting with the machinery needed to divide. Unable to replicate its genetic material, the virus fails to spread to other cells.
“This discovery shifts our understanding of the living cell. Rather than just a collection of static, membrane-bound compartments, the cell is now seen as a dynamic environment where membrane less organelles form spontaneously, much like oil droplets in water,” Dr Deshmukh says.
"These proteins act like a molecular glue," says Dr 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."
These droplets, also known as biomolecular condensates, represent a shift in how scientists understand a living cell. "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 membrane less 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," Dr Deshmukh said.
Many viruses carry their genetic material in the form of double-stranded RNA. When plants are infected, they ramp up the production of specialised RNA-binding proteins that can recognise this viral genetic material. Some of these proteins attach to sites known as ‘Viral Replication Complexes to stall the virus’ ability to copy itself to prevent the spread within the plant.
Until now, scientists believed these RNA-binding proteins worked in a simple “lock-and-key” manner binding directly to viral RNA. However, using advanced tools such as Nuclear Magnetic Resonance (NMR) spectroscopy, fluorescence microscopy, and molecular dynamics simulations, the CCMB team discovered a far more dynamic process.
Researchers found that these proteins have a unique structural fold with charged surfaces that create “sticky” patches. Positively charged regions attract negatively charged ones, allowing the proteins to cluster together into an interconnected network. This network forms dense, gel-like droplets that can trap viral RNA. “These proteins act like molecular glue,” said Paul.
Plant cells effectively trap viral RNA through these droplets to prevent replication. These droplets or ‘biomolecular condensates’, are reshaping scientists’ understanding of how cells function. “We now see cells as a dynamic environment where membrane-less structures can form and dissolve like oil droplets in water,” said Deshmukh.
The findings could also have relevance for human health. Understanding how these sticky protein networks work could help researchers develop strategies to dissolve harmful protein clumps linked to neurodegenerative diseases or disrupt protective barriers around tumours. Ultimately, this knowledge could help new drugs design that target and manipulate these molecular interactions with precision, the release added.
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