"The groundwork of all happiness is health." - Leigh Hunt

Discovery: Plants use 'Trojan horses' to fight mold attacks.

UC Riverside scientists have discovered a stealth molecular weapon that plants use to attack the cells of invasive gray mold.

If you've ever seen a fuzzy piece of fruit in your fridge, you've seen gray mold. It is an aggressive fungus that infects greater than 1,400 different plant species: just about all fruits, vegetables and lots of flowers. It is the second most damaging fungus to food crops on this planet, causing billions in crop losses annually.

A brand new journal paper describes how plants send tiny, harmless-looking lipid “bubbles” across enemy lines into RNA-laden, aggressive host cells. Once inside, various kinds of RNA come out to suppress the infectious cells that sucked them up.

“Plants aren't just sitting there doing nothing, they're trying to protect themselves from rotting, and now we have a better idea of ​​how they're doing it,” said Hailing Jin, of microbiology and plant pathology at UCR. said the department's professor and lead creator. of latest paper.

Earlier, Jin's team discovered that plants are using bubbles, technically called extracellular vesicles, to deliver small RNA molecules that silence genes that make mold toxic. are Now, the team has learned that these bubbles may contain messenger RNA, or mRNA, molecules that attack essential cellular processes, including the functions of organelles in mold cells.

“These mRNAs can encode some proteins that end up in the mitochondria of mold cells. They are the powerhouses of any cell because they produce energy,” Jin explained. “Once inside, they disrupt the structure and function of fungal mitochondria, which inhibits fungal growth and virulence.”

It isn't entirely clear why fungi accept lipid bubbles. Who theorized that they may be hungry. “Fungi probably take over the vesicles because they just want nutrients. They don't know that the RNAs are hidden in the vesicles,” he said.

This strategy is a useful one for plants, as a single mRNA molecule can have a big effect on fungi. “The beauty of delivering mRNA, rather than other forms of molecular weapons, is that one RNA can be translated into many copies of a protein,” Jin said. increases,” Jin said.

Molds also use these same lipid bubbles to deliver small, harmful RNAs into the plants they're infecting to suppress host immunity, a capability developed as a part of a co-evolutionary arms race. Is. Because RNAs are easily degraded, bubbles provide excellent protection for the transport of fragile cargo in each plants and fungi.

“During infection, there's always a lot of communication and molecular exchange where the plant and the fungus try to fight each other,” Jin said. “Earlier people looked at protein exchange. Now advanced technology has enabled us to discover another important group of players in this battle.”

Going forward, scientists hope to make use of this discovery to create modern, environmentally friendly fungicides. “RNA-based fungicides will not release toxic residues into the environment and will not affect humans or animals. RNA is present in most foods, and it is easily digested,” Jin said.

“It's a never-ending battle to control pests and pathogens. If we can deliver mRNA that interferes with mold cellular functions, we can help plants fight that battle more effectively. “