Recently, we demonstrated a new mechanism in DON regulation, revealed the relationship between cAMP-mediated signaling and DON biosynthesis in Fusarium graminearum. Fusarium head blight (FHB) caused by F. graminearum is a major threat to global wheat production. In addition to severe yield losses and grain quality reduction, F. graminearum produces trichothecene mycotoxin deoxynivalenol (DON) and other toxic secondary metabolites in infested grains. Thus, it is very important to study the mechanism of DON regulation in order to prevent fusarium head blight. In this study, researchers showed that cAMP treatment induced DON production by stimulating TRI gene expression and DON-associated cellular differentiation in F. graminearum. Although the two cAMP phosphodiesterase genes PDE1 and PDE2 had overlapping functions in vegetative growth, conidiation, sexual reproduction, and plant infection, Deletion of PDE2 but not PDE1 activated intracellular PKA activities and increased DON production. They also revealed that TRI6 was essential for the regulation of DON biosynthesis by cAMP signaling but elevated PKA activities could partially bypass the requirement of TRI10 for TRI gene-expression and DON production, and Pde2 was the major cAMP phosphodiesterase to negatively regulate DON biosynthesis in F. graminearum.
This discovery was published online on Environmental Microbiology.