Two important crop-destroying fungi, Fusarium graminearum and F. oxysporum, rely differently on a metabolic enzyme called pyruvate carboxylase to cause disease. Researchers found that removing this enzyme completely eliminates the ability of F. oxysporum to infect tomato plants by blocking its capacity to penetrate roots and break down plant cell walls. However, the same enzyme deletion has minimal effect on F. graminearum’s ability to infect wheat, suggesting these fungi have evolved different metabolic strategies for attacking their hosts.