Sanger chromatogram and barcode data for seven culture-derived microbial isolates from surface-sterilized leaves of the cultivated fern Cyrtomium fortunei

Background Historical Sanger-sequencing records can become difficult to reuse when raw chromatograms, sequence exports, accession identifiers, historical similarity-search outputs, and contextual metadata are preserved separately or incompletely documented. This Data Note describes a traceable archive for seven accessioned barcode records from culture-derived microbial isolates recovered from surface-sterilized leaf tissue of a long-term cultivated Cyrtomium fortunei plant. The resource is presented as an archival barcode dataset rather than as a survey of fern-associated microbial diversity. Methods The underlying data package is deposited in Zenodo. The seven records comprise five fungal ITS1 and two bacterial partial 16S rRNA barcodes associated with DDBJ/EMBL/GenBank accessions LC750340.1-LC750346.1. The host was identified as Cyrtomium fortunei by Ryo Ootsuki; voucher MAK 484653 is deposited in the Makino Herbarium (MAK), Tokyo Metropolitan University. Direct file-level validation showed that all 14 target-marker AB1 chromatograms have corresponding same-primer.seq exports and that every ABIF base-called sequence exactly matches its paired export across the complete base-called read. Historical similarity-search materials are retained as archival metadata rather than current taxonomic authority. Conclusions The dataset is intended for transparent reuse, Sanger-chromatogram inspection, barcode re-annotation, accession tracking, record-level audit, and practical bioinformatics teaching. It is not suitable for estimating endophyte prevalence, community composition, host specificity, or microbial function. Because surface-imprint, final-rinse, culture-blank, and sequencing-negative-control data are unavailable, and because the living cultures have been lost, the records are described conservatively as culture-derived microbial isolates rather than as confirmed endophytes.