Chromosome-level genome assembly of the social amoeba Heterostelium pallidum

Heterostelium pallidum is the type species in the genus Heterostelium. Its distinctive characteristics in sorocarp morphogenesis such as the formation of branched structures make this species a crucial model for studying the development and evolution of dictyostelids. However, the lack of a high-quality reference genome for this species has significantly impeded reliable comparative genomic and evolutionary studies. In this study, we present the first high-quality, chromosome-level genome assembly for H. pallidum, generated by integrating Illumina, PacBio HiFi, and Hi-C sequencing technologies. The assembled genome size is 33.07 Mb with a scaffold N50 of 2.61 Mb. A total of 95.26% of the assembled sequences were anchored onto 12 chromosomes. BUSCO assessment revealed a genome completeness of 92.60%. Genome annotation identified 16.38% repetitive sequences and 10,854 protein-coding genes. This chromosome-scale assembly represents the first genomic resource of this level of quality in the genus Heterostelium, the third example in the Dictyostelia. This high-quality genome assembly serves as an essential molecular resource, which will facilitate reliable comparative genomic studies across the Dictyostelia and enable investigations into the genetic basis of its unique branched sorocarp development and the evolution of multicellularity.