Study of the Multiple Roles of Phosphatidylinositol-4-Kinases Betas in Morphogenesis and Defense Responses of Arabidopsis Thaliana

The study investigated the roles of phosphatidylinositol 4-kinases (PI4Ks) in Arabidopsis thaliana, focusing on the pi4kβ1β2 double mutant. This mutant exhibited impaired root growth, altered auxin response, and changes in actin cytoskeleton and intracellular trafficking. The study also explored the plant's interaction with the fungus Blumeria graminis, revealing that the mutant had reduced resistance due to decreased PI4P levels in papillae, which are crucial for defense. Additionally, the pi4kβ1β2 mutant showed constitutively active immunity with salicylic acid (SA) accumulation, leading to dwarfism. The research suggested that WRKY70 might play a role in this SA accumulation, as crossing the mutant with wrky70 resulted in a phenotype closer to the wild type.