The expression pattern of EXO70 subunits in single-cell stereo-seq of Arabidopsis thaliana leaves using coexistence network analysis

The exocyst component of 70 kDa (EXO70) family in Arabidopsis thaliana comprises at least 23 isoforms, which are crucial for vesicular trafficking via the exocyst complex. However, the heterogeneity of its expression in leaves remains poorly understood. We analyze single-cell stereo-seq from StomicsDB to map the expression patterns of EXO70 subunits in epidermal, mesophyll, and vascular cells, addressing the challenges of sparse gene detection (≈ 2.5% expressed per cell) with a coexistence network framework. We identified cell-type-specific interactions among exocyst subunit EXO70 isoforms, exocyst complex components, and vesicle-associated protein (VAP) members by converting sparse transcriptomic data into binary matrices and calculating coexistence ratios. The results demonstrate that, within Spongy mesophyll cells, EXO70A1, EXO70H7, and exocyst subunit Sec3a (SEC3A) exhibit a significant co-occurrence, as indicated by coexistence permutation tests and correlation analyses. Our findings emphasize the functional specialization of EXO70 isoforms across leaf cell types and validate coexistence networks for analyzing low-expression gene families in complex tissues. This study presents a potential method for examining transcriptional regulators and signaling kinases in single-cell spatial omics.