Scientists have discovered a genetic mechanism that could stop the spread of a disease that threatens wheat crops.

Septoria leaf blotch (STB), which is caused by a fungus, is the most significant threat to wheat yields in most areas of the world, partly because it is increasingly resistant to currently available fungicides. Researchers at Durham University, working with partners from Newcastle University and Rothamsted Research, have now devised a technique that could to stop extensive spreading of STB disease. The work centred on a key feature of STB, the long symptomless growth of the fungus called Zymoseptoria tritici, which can affect the host plant’s cells before it becomes apparent and destroys the plant’s leaves.

The researchers found that a wheat protein, TaR1, was key in enabling Zymoseptoria tritici to maintain this symptomless growth. By manipulating TaR1 protein levels in wheat, either by conventional breeding or genetic modification in plants grown in laboratories, the researchers demonstrated that they could activate the plant’s defences earlier. The work is important because more than a third of wheat yield can be lost due to STB and it is the most significant disease of wheat in Europe and many other temperate climates.

Lead author Dr Ari Sadanandom, in the Durham Centre for Crop Improvement Technology, Durham University, said: “The foundation of global food security is built on three cereals, wheat, rice and maize, and wheat is the leading source of vegetable protein in human food. “STB drastically affects yield by destroying the leaves on wheat plants, reducing their capacity to carry out the photosynthesis needed for grain production. “It’s a significant threat as the fungicides that are currently the only control for this disease become less effective. “However our findings show that by manipulating the TaR1 protein we can create unfavorable conditions preventing the spread of STB in the plant, potentially providing a new strategy for combating this devastating disease.” The research was funded by the Biotechnology and Biological Sciences Research Council (BBSRC), Syngenta and the European Research Council (ERC).