All cereals, except rice, are susceptible to rust. Wheat, maize, barley, millet, triticale, and oats all get rust. The spores of rust fungi land on a host plant, germinate, and grow toward a stomatal pore on the leaf surface to initiate infection. Rust infections produce red or yellow pustulating spores that give infected plants a “rusty” look. In susceptible plants, rust cuts off the plants’ ability to photosynthesise nutrients in their leaves and transport nutrients in their stems, causing stems to weaken and plants to fall over, making what little yield there is nearly impossible to harvest.
Rice, the “stainless steel” among cereal grasses, has long intrigued plant breeders and plant pathologists. For decades scientists have believed that, by discovering the genes that make rice immune to rusts, they might be able to introduce these genes into other cereal grains such as wheat and maize.