Genome-Wide Identification and Expression Dynamics of ABC Transporters in Morchella sextelata During Fruiting Body Development and Selenium Supplementation

ATP-binding cassette (ABC) transporters constitute a superfamily of transmembrane transport proteins that are ubiquitously present across prokaryotic and eukaryotic organisms, exhibiting extensive substrate diversity and significant functional versatility. Yet, systematic genome-wide characterization of ABC transporters in Morchellasextelata remains largely unexplored. Here, a total of 33 ABC transporter genes were identified in M. sextelata and classified into eight subfamilies: ABCA (1), ABCB (7), ABCC (5), ABCD (6), ABCE (1), ABCF (4), ABCG (7), and ABCI (2), based on the features of domain composition and topology. These genes were unevenly distributed across 15 scaffolds, encoding proteins of 276–1626 aa (30.54–180.90 kDa) with pI values of 5.40–9.62 (16 acidic, 17 basic). Subcellular localization predictions indicated 24 MsABCs target the cell membrane, with others localizing to mitochondria, cytoplasm, or nucleus. Motif analysis identified 10 conserved motifs; all members harbor 1–2 copies of Motif 1, corresponding to the ATP-binding/Walker B region of the nucleotide-binding domain. Phylogenetically, ABC transporters form 7 major clades that align tightly with subfamily grouping. Promoter analysis revealed 67 distinct cis-element types grouped into 7 functional categories, with MYB (myeloblastosis) transcription factor binding motifs being the most frequent. Expression profiling showed 20 MsABCs were induced by 10 mg/L potassium selenite; during fruiting body morphogenesis, 19 MsABCs exhibited induced expression at late developmental stages, while nine genes maintained constitutively high expression across all stages. Thirteen MsABCs displayed higher transcript abundance in mycelium, four MsABCs were highly expressed in the stipe, and 14 MsABCs were highly expressed in the pileus. Collectively, our findings elucidate the genetic architecture of the M. sextelata ABC transporter family and delineate their expression dynamics under selenite supplementation, during fruiting body development, and across tissues, thereby establishing a framework for future functional characterization and utilization.