Plants are equipped with multiple layers of immune systems to defend themselves against pathogens. They are pattern-triggered immunity (PTI) activated when the plant cells first encounter the pathogens and effector-triggered immunity (ETI) which is induced by the recognition of effectors secreted by the pathogens inside the plant cells. I am interested in how various cell types respond during immune activation. To address this question, I study immune responses in Arabidopsis thaliana leaf using single-cell sequencing in the collaboration with Marja Timmermans’s group at the University of Tübingen.