Cell-Type Specific Autophagy Regulates the Dynamics of Pseudomonas syringae Infection in Arabidopsis

Shanshuo Zhu, Gautier Langin, Pavel Solansky, Thomas Denyer, Marja Timmermans, Suyab Uestuen
Faculty of Biology & Biotechnology, Ruhr-University Bochum, 44780 Bochum, Germany

As a conserved proteolytic pathway, the role of autophagy in immunity is increasingly recognized. Studies on autophagy pathways contributing to both host cell immunity and bacterial interaction have become increasingly evident. However, there is a lack of knowledge regarding how bacteria modulate this pathway in a cell-type-specific manner. Here, by utilizing single-cell transcriptomics of wild-type Arabidopsis thaliana Col-0 and autophagy-defective mutant (atg5) infected by virulent bacterial pathogen Pseudomonas syringae pv. tomato DC3000 (Pst), we compared cell-type-specific pathogen responses between the two genotypes. We show that Pst strongly activates autophagy in guard cells early in the infection to open stomata, thus supporting bacterial proliferation. We further identify that autophagy targets the ABA receptor to regulate ABA signaling and stomatal opening during infection. Moreover, autophagy also plays a role in controlling stomatal density to modulate plant-bacterial interactions. In addition to its role in innate immunity, the atg5 mutant exhibits enhanced immunity in mesophyll cells and is primed for stress. Our study unravels the microbe-modulated autophagy response at single-cell resolution and provides evidence for cell-type-specific roles of autophagy in immunity.