Transcriptomic regulatory mechanisms of Zostera caespitosa under different temperatures

To investigate the molecular mechanisms of the aquatic plant Zostera caespitosa in response to temperature stress, this study analyzed its transcriptomic response characteristics under low and high temperature stresses. Through transcriptome sequencing of Z. caespitosa under 5 °C (low temperature) and 25 °C (high temperature) treatments, combined with GO functional annotation and enrichment analysis, KEGG pathway enrichment analysis, and WGCNA gene co-expression network analysis, we systematically dissected the functions of differentially expressed genes (DEGs) and their associations with phenotypic traits. The results showed significant differences in the response strategies of Z. caespitosa to low and high temperatures. At 5 °C, gene expression regulation focused on enhancing membrane stability (e.g., enriched in membrane components and linoleic acid metabolism) and protein processing, while suppressing energy-consuming processes such as ribosome biogenesis and photosynthesis. At 25 °C, the response features involved activation of brassinosteroid biosynthesis, hormone signal transduction, and other growth-related pathways, with photosynthesis-related genes also suppressed. WGCNA analysis further identified MEred and MEturquoise as two key co-expression modules, where the MEred module was significantly positively correlated with biomass and photosynthetic parameters and specifically upregulated under high temperature, revealing the important role of core gene networks in coordinating growth and stress responses. This study systematically revealed the complex transcriptomic regulatory network of Z. caespitosa in response to temperature stress, providing an important molecular basis for a deeper understanding of stress resistance mechanisms in aquatic plants.