Gabani, V. | bioRxiv Science

bioRxiv2026

A bacterial lipid triggers membrane mechanosensing immunity in Arabidopsis

The plant immune system engages cell-surface receptors that detect microbe-associated molecular patterns to initiate pattern-triggered immunity (PTI), and intracellular receptors that sense microbe-secreted effectors to activate effector-triggered immunity (ETI). Whether additional modes of microbial detection exist remains unclear. Here, we define membrane mechanosensing immunity (MSI), a third layer of immune signaling. A bacterial lipid, the main diffusible signal factor (DSF) from Xanthomonas campestris pv. campestris, acts as a membrane-active molecule that alters plasma membrane biophysical properties, activates Mechanosensitive Channel of Small Conductance (MscS)-like (MSL)-dependent immune signaling, and triggers a broad transcriptional reprogramming that overlaps with PTI and ETI. MSI modulates PTI signaling and requires both PTI and ETI components for effective disease resistance. These findings establish the sensing of metabolite-induced membrane perturbations as a mechanism of microbial detection.

plant biology↗

bioRxiv2026

Plasma membrane nanoscale dynamics of Arabidopsis leucine-rich repeat receptor kinase complexes

Plasma membrane-localized receptors operate as dynamic signaling complexes and integrative networks1-3, yet the spatial and temporal regulation of these interactions remain largely unknown. Here, by analyzing the components of a minimal Arabidopsis leucine-rich repeat receptor kinase network, we describe the differential diffusion and organization of receptor complex components and unveil the nanoscale spatial and temporal logic underlying the formation of receptor kinase complexes. The ligand-binding receptors FLS2 and BRI1, and the accessory receptor BIR3, are organized in plasma membrane nanodomains, within which the co-receptor BAK1 diffuses and is spatially arrested upon ligand perception. BAK1s spatial arrest relies on extracellular domain (ECD)-ECD interactions but does not require receptor complex activation. Mathematical modelling, single molecule imaging and bio-assays infer that accessory receptors maintain a dynamic pool of co-receptors in the vicinity of ligand-binding receptors to promote ligand-induced complex formation and signaling. We propose that ligand-induced receptor kinase complex formation is a deterministic process defined by the relative nanoscale spatial positioning of individual signaling and regulatory components.

cell biology↗