Identification and Evolution of Exon Junction Complex Core Genes and Expression Profiles in Moso Bamboo

The exon junction complex (EJC) is a central mediator of post-transcriptional regulation in eukaryotes. A comprehensive, systematic analysis of EJC core genes has been lacking in Phyllostachys edulis (P. edulis). Here, we identified 147 EJC core genes across 17 plant species spanning the major green plant lineages. Phylogenetic analyses supported each family as a monophyletic clade consistent with established taxonomic relationships. Synteny analyses indicated that segmental duplication is the principal driver of EJC core gene expansion in P. edulis (Moso bamboo). Transcriptome profiling further showed that nearly all PedEJCs were engaged during rapid shoot growth, with PedY14b-D, PedY14c-D, and PedY14d-C displaying the most pronounced expression changes. During shoots’ post-harvest senescence process, PedEIF4A3s, PedY14s, and PedMAGOs were progressively downregulated, whereas PedBTZs were upregulated, indicating distinct module-level responses among EJC subunits. Only a small subset of PedEJCs responds to phytohormones and abiotic stresses. Furthermore, cis-regulatory element composition in promoter region likely shapes PedEJCs transcriptional regulation. Collectively, these findings lay the groundwork for in-depth functional dissection of PedEJCs in Moso bamboo.