Regulators of nitric oxide signaling triggered by host perception in a plant pathogen

Significance Understanding belowground communications between plant roots and soil microbes is enormously important for crop production. However, in contrast to plant–beneficial microbe interactions, signaling events underpinning root–fungal pathogen interactions are poorly understood. In this study, we specifically addressed this knowledge gap inFusarium graminearum , one of the most devastating fungal pathogens of cereal crops throughout the world. We showed that sensing of host signals byF. graminearum before physical contact with roots triggers nitric oxide (NO) production in the pathogen. We identified two proteins that physically interact to regulate NO production and virulence in this pathogen. Our results provide mechanistic insights into host-perception processes that can be manipulated to develop novel plant-protection strategies.