The Arabidopsis G-Protein beta-Subunit Is Required for Defense Response against Agrobacterium tumefaciens

Typical early pathogen-associated molecular pattern (PAMP) responses include the generation of reactive oxygen species (ROS) and MAP kinase (MAPK) activation, but little is known about the molecular mechanisms that link receptor activation to intracellular signal transduction. In this study, we found that in agb1-2 (AGB1 null mutation) mutants, ROS production triggered by flg22 or elf18 was significantly reduced and that elf18-stimulated PAMP-triggered immunity (PTI) against Agrobacterium tumefaciens was impaired. Thus AGB1 appears to integrate PAMP perception into downstream ROS production, and also to transmit the EF-Tu signal to the defense response, leading to reduced transformation by A. tumefaciens.