Body of Abstract: Plasmodesmata (PD) are membrane-lined channels that provide physical connections between adjoining plant cells, serving as communication channels. Given their fundamental roles, PD is important for plant survival and defense. It has been reported that PD-located proteins (PDLPs) play important roles in plant immunity. In Arabidopsis thaliana, PD-located-protein5 (PDLP5) regulates PD function through an unknown mechanism. The expression of PDLP5 is upregulated by bacterial infection, whereas Pseudomonas syringae (Pst) effector HopO1-1 targets Arabidopsis PDLP5 and PDLP7. We recently implemented enzyme-catalyzed proximity labeling (PL) to identify functional partners of PDLP5. We further utilized the PL assay to capture the dynamic changes in PDLP5-containing protein complexes upon Pst infection. We identified over 200 proteins that might function with PDLP5 during bacterial infection. We initially focus on cysteine-rich receptor-like kinases (CRKs). CRK2 has been reported to function at PD and phosphorylates NADPH/respiratory burst oxidase protein D (RBOHD). Using AlphaFold-Multimer, we predicted CRKs-PDLP5, CRKs-RBOHD, and CRKs-RBOHF heterodimers. Our preliminary data suggest the role of the CRKs as negative regulators of callose accumulation at PD and plant immunity against bacterial infection. We hypothesize that CRKs regulates reactive oxygen species production during bacterial infection to regulate the plasmodesmata function and plant immunity. Our study demonstrates the power of the PL assay in studying the dynamic regulation of PD during plant immunity.