Australian, American and South African researchers have discovered the origins of the deadliest strain of wheat stem rust. The disease is one of the most dangerous, threatening global food security. Their research which was published in Nature Communications divulges that the fungus strain (Ug99) is a hybrid which was created when different rust strains fused. It was found that the hybrid’s material came from a strain that has existed in southern Africa for over 100 years as well as Australia. The study states that Ug99 could again exchange genetic material with other micro-organisms to create another new strain. "This discovery will make it possible to develop better methods to screen for varieties with strong resistance to disease," Dr Melania Figueroa said.