Near-complete telomere-to-telomere genome assembly of a millennium-old ancient Pteroceltis tatarinowii (Qingtan, Cannabaceae) tree
Pteroceltis tatarinowii is a monotypic relict species endemic to China. It belongs to the genus Pteroceltis in the family Cannabaceae, and is an economically and culturally valuable fiber-producing tree species. We integrated PacBio HiFi, Oxford Nanopore Technology (ONT), and Hi-C chromatin conformation capture data to generate a near-complete telomere-to-telomere genome assembly of a millennium-old P. tatarinowii tree. The final assembly spanned approximately 689 Mb, with a contig N50 of 35.0 Mb; 99.88% of the sequences were successfully mapped onto chromosomes, with only two gaps remaining in the genome, showing a marked improvement in assembly continuity over previously published P. tatarinowii assemblies. We predicted a total of 47,241 protein-coding genes; repetitive sequences accounted for 48.37% of the genome, with long terminal repeat retrotransposons as the dominant component (18.92%). Benchmarking Universal Single-Copy Orthologs assessment confirmed genome completeness of 98.6% and gene annotation completeness of 98.7%. We resolved key complex genomic regions, including telomeres and centromeres, and this high-quality assembly provided a foundational genomic resource to clarify the taxonomic status of P. tatarinowii and formulate scientific genetic conservation strategies for this endangered relict species.