Gray mold, a notorious culprit causing billions in crop losses annually by infecting berries, tomatoes, and numerous other fruits and vegetables, may finally meet its match. Excitingly, researchers at UC Riverside have recently made a groundbreaking discovery that could revolutionize crop protection and eliminate the need for toxic chemical treatments.
Gray mold, scientifically known as Botrytis cinerea, affects more than 1,400 plant species, and unfortunately, there has been no effective cure for this devastating disease. However, the latest UC Riverside research reveals that lipid “bubbles” secreted by mold cells are integral to the mold's communication with its host, as well as other pathogens such as fungi, bacteria, and mammals.
For decades, these lipid-based bubbles, also known as extracellular vesicles, were overlooked due to their difficulty in isolation and study. But now, researchers have uncovered the mold's strategy of using these vesicles to its advantage, delivering small RNA molecules that silence genes involved in the plants' immune systems. This allows the mold to achieve successful infections and spread rapidly.
Lead researcher Hailing Jin, UCR professor of microbiology and plant pathology, emphasized the significance of these findings. “Because they are hard to isolate and study, the important functions of these lipid bubbles, also called extracellular vesicles, have been overlooked for decades. Now we know the mold, just like its plant hosts, also uses extracellular vesicles to protect and deliver what amount to weapons—small RNA molecules that silence genes involved in plants' immune systems.”
The study, detailed in the journal Nature Communications, not only demonstrates that gray mold secretes virulent RNA through these lipid-based bubbles but also identifies a crucial protein called tetraspanin responsible for their production. When researchers disrupted the mold's ability to produce tetraspanin, the secretion and delivery of the vesicles were significantly reduced.
Jin highlighted the potential implications of targeting tetraspanin and certain genes responsible for small RNA molecule production. By creating a new generation of “RNA fungicides,” it might be possible to inhibit gray mold disease without resorting to harmful chemicals. This promising approach could pave the way for an eco-friendly solution to safeguarding global food supplies.
“Everything has RNA in it, and it is easily digested by humans and animals. RNA can be degraded quickly in the environment and wouldn't leave any toxic residues,” Jin explained. Unlike current fungicides that can negatively impact human and animal health and the environment, RNA-based treatments hold the promise of being environmentally friendly and safe.
Gray mold ranks as the second most damaging fungus for food crops worldwide, second only to the rice pathogen Magnaporthe. The research team envisions that an RNA-based fungicide approach, disrupting the ability to secrete extracellular vesicles, could also prove effective against Magnaporthe and other fungal pathogens.
“With the climate changing so fast, many fungal infections can get worse. We are excited to develop new eco-friendly methods of protecting the global food supply that may be so widely applicable,” Jin concluded optimistically.
This groundbreaking research could be a game-changer in combatting gray mold and other crop-damaging fungi, presenting a sustainable and eco-friendly solution for ensuring food security amidst the challenges posed by climate change.