From effector biology to durable genetic resistance: Insights from the tomato leaf mould pathosystem

Leaf mould is a fungal disease that damages tomato leaves and can reduce yields. Resistant tomato varieties help growers control the disease, but the fungus can evolve to overcome their defences. Christiaan Schol investigated how this happens and how wild tomato relatives can provide new sources of resistance. He identified fungal proteins recognised by tomato plants and showed how changes in, or loss of, these proteins allow the fungus to escape detection. He also mapped new sources of fungal recognition in wild tomatoes and identified a gene that allows plants to recognise a specific fungal protein. Together, the findings explain the breakdown of existing resistance and expand the genetic resources available for breeding. They show why developing more durable resistance requires understanding both the plant’s immune system and the fungus’s capacity to adapt. This knowledge can help breeders make better use of resistance genes and support more sustainable tomato production.