Genome editing of phosphoinositide 4-kinases enhances resistance to bacterial and fungal pathogens in rice

Stable rice production is continuously threatened by rapidly evolving, devastating rice pathogens, underscoring the need for new sources of disease resistance. Phosphoinositide 4-kinases (PI4Ks) are important in the phosphoinositide biosynthetic pathway and are classified into Type II and Type III. Type III PI4Ks have been studied for their role in plant immunity; however, the function of Type II PI4Ks remains underexplored. In this study, we investigated the role of type II PI4Ks, OsPI4Kγ2 and OsPI4Kγ6 in rice immunity. Using genome editing, we generated knockout mutants of OsPI4Kγ2 and OsPI4Kγ6, which displayed enhanced resistance to rice blast and bacterial blight as indicated by reduced disease symptoms, increased production of reactive oxygen species (ROS), and elevated defense-related gene expression. Moreover, loss of OsPI4Kγ2 or OsPI4Kγ6 significantly reduced PtdIns4P levels and biotrophic interfacial complex (BIC) formation rates, indicating that these kinases are required for maintaining normal PtdIns4P homeostasis and infection-related structure formation in rice. This study thus provides evidence that OsPI4Kγ2 and OsPI4Kγ6 act as negative regulators of rice immunity, offering new insights into their role in plant defense.