Prestigious ERC Advanced Grant awarded to Professor Peter Brodersen

The European Research Council (ERC)’s Advanced Grant is one of the most prestigious and competitive funding schemes in the EU. It gives senior researchers the opportunity to pursue ambitious, curiosity-driven projects that could lead to major scientific breakthroughs.

- Receiving 2.5 million Euros of funding through such a prestigious grant really makes a difference – it allows my research group to be ambitious about what new discoveries we can achieve the next 5 years, diving deeper into the fundamental mechanisms of plant immunity. Receiving such a recognition, I can’t help but feel a bit proud as a researcher, says Professor Peter Brodersen.

Plants have a backup plan when viruses strike

Traditionally, it was believed that plants rely solely on RNA interference (RNAi) as their basal antiviral immune system. In this process, the enzymes DICER-LIKE4 (DCL4) and DICER-LIKE2 (DCL2) cut viral double-stranded RNA (dsRNA) into small pieces that in turn program an efficient RNA destruction machine to target only viral RNA. The biochemical principle of that specificity is well-known: it is exactly the same as the force that keeps the two strands of the DNA double helix together. 

However, recent discoveries from Peter Brodersen’s laboratory have revealed that this view is incomplete. While DCL4 plays a primary role in RNA interference, DCL2 has an additional function: it can sense alarmingly high concentrations of double-stranded RNA and trigger an innate immune response, especially when viruses suppress the RNA interference defense mechanism provided by DCL4. This immune response involves DCL2 signaling to immune receptors, which activate defense signaling to establish an immune state in the plant.

“If the first line of defense falls, the plant cell enters an immune state. It then restructures how it basically functions – it stops all activities not related to fighting the infection, and might even program itself to die, to prevent the infection spreading to other cells”, says Peter Brodersen.

Unravelling the plant immune system to create virus resistant crops

Building on this new understanding, the current research seeks to uncover the molecular mechanisms of this second line of defense against viral infection. This includes the investigation of how DCL2 generates a signal, what the nature of the signal is, and how the immune receptor recognizes the signal (which triggers a signaling cascade that activates the immune state of emergency in the cell).

Understanding more about how the immune system recognizes threats and what signals it uses to establish immunity might also lead to a deeper understanding of how viruses occasionally overcome both lines of defense.

“The project aims to improve the basic understanding of the molecular mechanisms behind one of the oldest and most fundamental struggles – the fight between living organisms and viruses. Further, if we know more about how the immune system in plants is triggered, we can trigger it manually before a virus is spread – potentially saving thousands of crops. Such knowledge might also hold potential to target specific types of viruses, or specific viral functions, that are normally used to overcome the plants’ two lines of immune defense.”, says Peter Brodersen.