脊尾白虾鳃组织单细胞图谱为揭示甲壳动物柱细胞介导的低盐适应机制提供新见解

Low-salinity stress exerts strong constraints on ion homeostasis in crustaceans cultivated in coastal environments. Gills function as central osmoregulatory organs in crustaceans, coordinating transepithelial ion flux and acid-base balance; however, the cellular mechanisms governing gill adaptation to reduced salinity remain poorly understood. Here, integrated ultrastructural characterization and single-cell RNA sequencing (scRNA-seq) were applied to define cellular responses to low-salinity exposure in <i>Exopalaemon carinicauda</i> gills. Low salinity induced pronounced morphological remodeling in pillar cells. Single-cell transcriptomic profiling resolved 11 transcriptionally distinct populations, including two ionocyte lineages represented by pillar cells and septal cells. Comparative analyses demonstrated a marked expansion of pillar cell subcluster 3 under low-salinity stress, accompanied by enrichment of differentially expressed genes (DEGs) in ion transport pathways, notably hydrogen ion transport. Weighted gene co-expression network analysis identified coordinated up-regulation of hub genes associated with pH regulation within pillar cells. Pseudotime reconstruction further indicated that gill adaptation to low-salinity stress proceeds through a defined differentiation trajectory (cell fate 1) originating from pillar cells. Core stress-responsive genes in pillar cells, including V(H ⁺)-ATPases and cytoplasmic carbonic anhydrase, were predominantly associated with acid-base regulation. Collectively, these results delineate gill cellular heterogeneity and identify pillar cell-mediated regulatory mechanisms that underpin crustacean physiological adaptation to low-salinity environments.