The Arabidopsis PSS1 gene, which encodes a glycine-rich protein, plays a pivotal role in nonhost resistance to the soybean oomycete Phytophthora sojae and the fungal pathogen Fusarium virguliforme. To elucidate the molecular basis of PSS1-mediated immunity, we employed miniTurbo-based proximity labeling in stable transgenic Arabidopsis lines expressing miniTurbo fused to either wild-type PSS1 or its nonfunctional mutant variant, PSS1G119D. Seedlings were challenged with or without P. sojae, and biotinylated proteins were isolated and analyzed by mass spectrometry. The resulting PSS1 interactomes revealed several candidate proteins predominantly localized in the plastid and cytosol. Notably, proteins such as LIN2, ATPMEPCRA, and TGG1 were specifically enriched in wild-type PSS1 lines under P. sojae infection, suggesting their potential involvement in PSS1-mediated nonhost resistance. Our findings offer novel insights into immune protein networks and provide a foundational resource for dissecting nonhost immunity mechanisms in plants