CymMV TGB1 targets Nicotiana benthamiana GSO1 kinase domain to reduce host resistance

Plant receptor-like kinases (RLKs) have been identified to regulate plant growth and development and immune signaling.
RLK containing leucine-rich repeats (LRR-RLK) named GASSHO1 (GSO1) was shown as a co-receptor involved with regulating embryo and root formation in Arabidopsis. In this study, Nicotiana benthamiana GSO1 (NbGSO1) was upregulated in transcriptome of Cymbidium mosaic virus (CymMV) and mix of CymMV + Odontoglossum ringspot virus (ORSV) infected N. benthamiana leaves at the initial stage of infection.
The NbGSO1 kinase domain was able to bind CymMV TGB1 (TGB1^Cy). However, co-immunoprecipitation and kinase assays showed that NbGSO1 did not phosphorylate TGB1^Cy. Tobacco rattle virus-based virus-induced gene silencing of NbGSO1 enhanced accumulation of CymMV and ORSV. Subcellular localization of NbGSO1 kinase domain and TGB1^Cy showed that they were located in cytoplasm of N. benthamiana leaves.
We propose that interaction of TGB1^Cy with NbGSO1 interferes NbGSO1 kinase function by blocking its binding to co-receptors such as the TIR domain of resistance gene or inhibits kinase activity of NbGSO1 to activate plant defense.

IV International Orchid Symposium

U. Petchthai, S.M. Wong

CymMV, RLKs, host resistance

https://doi.org/10.17660/ActaHortic.2024.1414.5