P-005 - A truncated, cytoplasmic Cysteine-rich Receptor-like Kinase (CRK) protein contributes to perception of gram-positive bacteria in Arabidopsis

Plants employ cell-surface receptor complexes to recognize immunogenic patterns, which upon activation trigger a suite of downstream signaling events. In these receptor complexes, receptor-like cytoplasmic kinases (RLCKs) are immediate downstream substrates of plasma membrane (PM)-localized receptor proteins and carry out signal transduction to intracellular downstream signaling components. Previous work in our lab (poster by Pierdzig et al.) revealed that perception of wall teichoic acid (WTA), a microbe-associated molecular pattern specific for gram-positive bacteria, is mediated by the PM-resident Cysteine-rich receptor-like kinase 7 (CRK7) and triggers a non-canonical defense response and programmed cell death in Arabidopsis. Here, we identified another member of the Arabidopsis CRK family, featured by a lack of both ecto- and transmembrane domains, which acts as an RLCK for WTA-induced responses. We demonstrate that CRK7 and this truncated CRK are part of the WTA receptor complex and provide evidence that the cytosolic localization and kinase activity of the latter plays an essential role in WTA-triggered immune signaling.