Gonzalez-Fuente, M. | bioRxiv Science

bioRxiv2026

Autophagy acts as a spatial organizer of cell-type-specific plant immunity

Effective plant immunity requires precise spatial coordination of immune responses across cell-types to restrict pathogens while preventing tissue damage, yet the intracellular pathways that organize this spatial architecture remain unknown. Here we show that autophagy serves as a spatial coordinator of immunity, partitioning and calibrating immune strategies across tissues during Pseudomonas syringae infection in Arabidopsis thaliana. Combining single-cell transcriptomics, cell-type-specific complementation, and live-cell imaging, we uncover distinct and opposing roles of autophagy across tissues. In guard cells, autophagy promotes pathogen-induced stomatal reopening by suppressing abscisic acid (ABA) signalling in part via autophagic turnover of the guard cell ABA receptor PYL4. In contrast, in mesophyll cells, autophagy restricts immune activation while simultaneously enabling effective immune execution: its loss enhances EDS1-PAD4-ADR1 pathway expression yet compromises PTI outputs. Mechanistically, bacterial infection triggers autophagic EDS1 turnover, supporting a model in which controlled EDS1 recycling facilitates HR elicitation. Cell-type-specific complementation reveals that PTI competence may involve coordinated autophagy across tissues, whereas mesophyll-autonomous autophagy is partially sufficient for HR execution. Together, these findings establish a framework in which spatial control of proteostasis orchestrates multicellular immune coordination, with broad implications for understanding how conserved degradation pathways regulate layered immunity across organisms.

plant biology↗

bioRxiv2025

Effector-triggered processing body formation attenuates host translation via ER stress responses and autophagy upon bacterial infection

Pathogens employ sophisticated strategies to modulate host protein homeostasis by targeting proteolytic pathways, but their impact on protein synthesis remains elusive. We report that pathogenic bacteria Pseudomonas syringae (Pst) targets ribonucleoprotein condensates, known as processing bodies (P-bodies), to attenuate host translation through two effectors with liquid-like properties. We uncovered a previously unknown link that Pst-mediated repression of the ER stress response is required for P-body assembly. Furthermore, we identify a novel intersection between P-bodies and autophagy, demonstrating that autophagic clearance of P-bodies is crucial for maintaining the balance between translationally active and inactive mRNAs. Altogether, our discoveries provide novel insights on how host translation is attenuated by bacteria to dampen plant immunity and uncover unknown connections between ER stress responses and autophagy with P-body dynamics.

plant biology↗

bioRxiv2019

EffectorK, a comprehensive resource to mine for pathogen effector targets in the Arabidopsis proteome

Pathogens deploy effector proteins that interact with host proteins to manipulate the host physiology to the pathogens own benefit. However, effectors can also be recognized by host immune proteins leading to the activation of defense responses. Effectors are thus essential components in determining the outcome of plant-pathogen interactions. Despite major efforts to decipher effector functions, our current knowledge on effector biology is scattered and often limited. In this study, we conducted two systematic large-scale yeast two-hybrid screenings to detect interactions between Arabidopsis thaliana proteins and effectors from two vascular bacterial pathogens: Ralstonia pseudosolanacearum and Xanthomonas campestris. We then constructed an interactomic network focused on Arabidopsis and effector proteins from a wide variety of bacterial, oomycete, fungal and animal pathogens. This network contains our experimental data and protein-protein interactions from 2,035 peer-reviewed publications (48,200 Arabidopsis-Arabidopsis and 1,300 Arabidopsis-effector protein interactions). Our results show that effectors from different species interact with both common and specific Arabidopsis targets suggesting dual roles as modulators of generic and adaptive host processes. Network analyses revealed that effector targets, particularly effector hubs and bacterial core effector targets, occupy important positions for network organization as shown by their larger number of protein interactions and centrality. These interactomic data were incorporated in EffectorK, a new graph-oriented knowledge database that allows users to navigate the network, search for homology or find possible paths between host and/or effector proteins. EffectorK is available at www.effectork.org and allows users to submit their own interactomic data. Author summaryPlant pests and diseases caused by bacteria, oomycetes, fungi or animals are threatening food security worldwide. Understanding how these pathogens infect and manipulate the host is key to develop sustainable crop resistance in the long term. Effector proteins are secreted by pathogens to subvert the host immune responses. The roles of several effector proteins have been described; however, it is yet poorly understood how effectors interact with host proteins at a global level. To address this issue, we have generated EffectorK, an interactive database focused on the model plant species Arabidopsis thaliana. This database contains manually curated Arabidopsis-effector protein interactions from the available literature on a wide variety of pathogens. It also contains new experimental data on effectors from two vascular pathogens: Ralstonia pseudosolanacearum and Xanthomonas campestris. This work integrates all the gathered knowledge over the last decades and allows to identify general patterns of how effectors interact with the host proteome. This knowledge is easily accessible and searchable at www.effectork.org.

plant biology↗