Scientists explore genetics to halt spread of Ug99
New and more virulent crop diseases are predicted to emerge as a result of climate change. Scientists from the John Innes Centre and The Sainsbury Laboratory on Norwich Research Park are at the front line of fundamental research to understand the impact of temperature on pathogens, plants and how they interact. They will mine genetic diversity in crop relatives for new sources of disease resistance.
TSL scientists are enlisting a wild grass collected from coastal plains in Israel to protect wheat harvests from a disease that is already devastating crops from Uganda to Iran.
“The research highlights the importance of maintaining biodiversity,” said Dr Brande Wulff (photo) from The Sainsbury Laboratory.
Wild plants can harbour powerful resistance to crop diseases.”
The wispy, insignificant-looking grass Aegilops sharonensis, or Sharon goatgrass, grows on coastal plains in Israel and South Lebanon that are undergoing increasing development. Many populations of the grass are on the edge of extinction.
Scientists are growing it from seed in glasshouses at The Sainsbury Laboratory so they can identify the genes that protect it from Ug99, a stem rust fungus that could infect 80-90 per cent of wheat varieties worldwide. They have just received an additional half a million pounds of funding from BBSRC to identify and isolate the genes responsible for disease resistance.
The disease can spread rapidly over large distances by wind or by accidental human transmission. Stem rust pathogens can also evolve quickly and seven additional variants of Ug99 have been identified. The onward spread is highly likely.
“The immediate fear in terms of food security is that Ug99 will reach the Northern Punjab in Pakistan where nearly a fifth of the world’s wheat is grown,” said Dr Wulff.
Stem rust traditionally thrives in warmer climates and is only an occasional visitor in the UK, but Ug99 is more aggressive at lower temperatures compared to other strains. A longer term fear is that it could become established in more temperate regions of Europe.
“Rising temperatures and increasing drought are the most obvious threats to agriculture posed by climate change, but the greatest impact of climate change on yields could actually be the emergence of new pests and diseases,” said Dr Matthew Reynolds from CIMMYT, the International Maize and Wheat Improvement Centre.
Ug99, first identified in Uganda in 1999, is of particular concern because it has broken a key resistance gene in commercial wheat, Sr31, that has protected crops worldwide for three decades. It is also virulent against most other resistance genes in wheat and related species.