Researchers have identified a gene that makes some soybean varieties tolerant to the cyst nematode, a pathogen that can be responsible for $1 billion in annual losses in the U.S. soybean crop. The gene creates an enzyme that can starve nematodes. The discovery, published in the journal Nature, could lead to biotech soybeans with complete resistance, said Greg Tylka, a professor of plant pathology at Iowa State University, who was not involved in the study.