Disease and pest-resistant crops are a step closer after researchers uncovered how genes play their part in defending plants against these attacks.

The discovery, made by an international consortium of researchers, including a UK team headed by Jim Beynon at the University of Warwick, will make it possible to explore new avenues for crop improvement.

“Plants have a basic defence system to keep out potentially dangerous organisms,” said Prof Beynon. “Unfortunately, some of these organisms have, over time, evolved the ability to overcome plant defences and so plant breeders are always looking for new ways to catch them out.

“Understanding exactly how plant immunity works is key to making developments in this area.”

His team looked at downy mildew, which is caused by Hyaloperonospora parasitica. Like many organisms that infect plants, it produces proteins that it introduces into the plant to undermine its natural defences.

The team studied almost 100 different so-called effector proteins from H parasitica that are known to be involved in overcoming a plant’s immune system. They were looking to see how each of these proteins interacted with other proteins that are already present in a plant. They found a total of 122 plant proteins from the commonly-studied plant Arabidopsis thaliana (mouse-ear cress) that are directly targeted by the proteins from H parasitica.

Prof Beynon added: “This shows there are many more plant proteins involved in immunity than we first thought. By studying the genes that give rise to these proteins, we can start to identify key genetic targets for crop improvement.”

The study has also identified many complex connections between the plant proteins, suggesting the network of activity is crucial in plant defences.

The work was a collaboration between the Dana Faber Institute in Boston, the University of North Carolina, and a European consortium, including The Sainsbury Laboratory in Norwich, Utrecht University in The Netherlands, and the Max Planck Institute, Cologne. The UK part was funded by the Biotechnology and Biological Sciences Research Council.