Although intensive studies have been performed to identify and characterize host factors involved in viral replication complex formation, the high dynamism of this process and the insoluble properties of the complex make it difficult to be analyzed comprehensively using traditional affinity purification methods. TurboID-based proximity labeling emerges as a robust tool for probing molecular interactions in planta, yet there is no report on the application of TurboID on the study of plant virus replication. Here, we used Beet black scorch virus (BBSV), an endoplasmic reticulum-replicating virus, as a model, and systematically investigated the composition of BBSV virus replication complex (VRC) by fusing the TurboID enzyme to viral replicase protein p23. Among the 185 identified p23-proximal proteins, reticulon family proteins showed high reproducibility in the mass spectrometry datasets. We focused on the reticulon-like protein B2 (RTNLB2) and demonstrated its pro-viral functions in BBSV replication. Mechanistic analysis revealed that RTNLB2 binds to p23, induces the ER membrane curvature and constricts ER tubules to facilitate the assembly of BBSV VRC. Our comprehensive proximal interactome analysis of BBSV VRC provides a resource for understanding of plant viral replication and offers new insights into the formation of membrane scaffolds for viral RNA synthesis.