Refrigerators are great for storing food and keeping it fresh, but they can also be a breeding ground for fuzzy gray mold. Despite thriving in warm temperatures, many molds can grow in the refrigerator by producing spores that go airborne and infect fruits and vegetables. However, plants have a secret weapon against this creeping fungus. According to a study recently published in the journal Cell Host & Microbe, plants use a stealth molecular weapon to attack the cells of gray mold.
To find out more, a team of researchers delved into the molecular signaling of a plant called Arabidopsis thaliana–or Thale cress–against gray mold (Botrytis cinerea). They found that the plants deploy small lipid “bubbles” called extracellular vesicles, loaded with RNA and mRNA molecules that can counteract the aggressive mold cells.
“Plants are not just sitting there doing nothing. They are trying to protect themselves from the mold, and now we have a better idea how they’re doing that,” study co-author and University of California, Riverside microbiologist Hailing Jin said in a statement.
Jin’s team previously discovered that plants use similar “bubbles” to send small mRNA molecules that can silence the genes responsible for making the mold more dangerous. This recent study found that the bubbles contain mRNA molecules that attack the mold cells’ essential cellular processes.
“These mRNAs can encode some proteins that end up in the mitochondria of the mold cells. Those are the powerhouses of any cells because they generate energy,” said Jin. “Once inside, they mess up the structure and function of the fungal mitochondria, which inhibits the growth and virulence of the fungus.”
Interestingly, mold uses these same lipid bubbles to deliver small, damaging RNAs into the plants they infect.