Fungal Proteins: The Double Agents in Plant Infections

In the world of plant diseases, some proteins are like secret agents. They have a double life.

Helping the Fungus and Waking the Plant's Defenses

Scientists discovered six such proteins in a fungus called Verticillium dahliae. These proteins belong to a family known as GH7.

Step 1: Removing the Proteins

• The scientists removed each GH7 protein from the fungus.
• The fungus became less harmful but grew just fine.
• This showed that these proteins help the fungus cause disease but are not needed for growth.

Step 2: Tracking the Proteins

• Using special tools, scientists watched the proteins in action.
• The proteins moved into plant cells and ended up in the cytoplasm (the fluid part of the cell).
• Once there, they triggered the plant's defense system.

How the Plant Reacts

The plant's defense system acts like an alarm, causing:

1. Hypersensitive cell death (some plant cells die quickly).
2. Production of special molecules to fight the fungus.
3. Creation of callose, a substance that blocks the fungus from spreading.

How the Plant Knows to Defend Itself

• Two special plant proteins, SGT1 and NDR1, are crucial.
• If these proteins aren't working, the plant does not react to the GH7 proteins.
• This means the GH7 proteins trick the plant into turning on its defenses.

Why This Matters

• Some proteins can have two jobs: helping the fungus cause disease and helping the plant fight back.
• It's like a game of chess—the fungus and the plant are always trying to outsmart each other.
• This discovery gives us a new piece of the puzzle in understanding how plants and fungi have evolved together.