EXTRA LARGE G-PROTEIN 2 (XLG2) mediates cell death and hyperimmunity via a novel, apoplastic ROS-independent pathway in Arabidopsis thaliana

Petutschnig, E. K.; Anders, J.; Stolze, M.; Meusel, C.; Hacke, R.; Schwier, M. A.; Gippert, A.-L.; Kroll, S.; Fasshauer, P.; Wiermer, M.; Lipka, V.

doi:10.1101/2021.10.08.463358

bioRxiv · 10.1101/2021.10.08.463358

EXTRA LARGE G-PROTEIN 2 (XLG2) mediates cell death and hyperimmunity via a novel, apoplastic ROS-independent pathway in Arabidopsis thaliana

Petutschnig, E. K.·Anders, J.·Stolze, M.·Meusel, C.·Hacke, R.·Schwier, M. A.·Gippert, A.-L.·Kroll, S.·Fasshauer, P.·Wiermer, M.·Lipka, V.

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Abstract

O_LIHeterotrimeric G-Proteins are signal transduction complexes comprised of three subunits, G, G{beta} and G{gamma}, and are involved in many aspects of plant life. The non-canonical G subunit XLG2 mediates PAMP-induced ROS generation and immunity downstream of PRRs. A mutant of the chitin receptor component CERK1, cerk1-4, maintains normal chitin signalling capacity, but shows excessive cell death upon infection with powdery mildews. We identified XLG2 mutants as suppressors of the cerk1-4 phenotype. C_LIO_LIWe generated stably transformed Arabidopsis lines expressing Venus-XLG2 and numerous mutated variants. These were analysed by confocal microscopy, Western blotting and pathogen infection. We also crossed cerk1-4 with several mutants involved in immunity and analysed their phenotype. Phosphorylation of XLG2 was investigated by quantitative proteomics. C_LIO_LIMutations in XLG2 complex partners AGB1 and AGG1 have a partial cerk1-4 suppressor effect. The cerk1-4 phenotype is independent of NADPH oxidase-generated ROS, BAK1 and SOBIR1, but requires PUB2. XLG2 mediates cerk1-4 cell death at the cell periphery. Integrity of the XLG2 N-terminal domain, but not its phosphorylation, is essential for correct XLG2 localisation and cerk1-4 signalling. C_LIO_LIOur results suggest that XLG2 transduces signals from an unknown cell surface receptor that activates an apoplastic ROS-independent cell death pathway in Arabidopsis. C_LI

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Petutschnig, E. K., Anders, J., Stolze, M., Meusel, C., Hacke, R., Schwier, M. A., Gippert, A.-L., Kroll, S., Fasshauer, P., Wiermer, M., Lipka, V.. 2021-10-09. EXTRA LARGE G-PROTEIN 2 (XLG2) mediates cell death and hyperimmunity via a novel, apoplastic ROS-independent pathway in Arabidopsis thaliana. https://doi.org/10.1101/2021.10.08.463358

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