Chromosome-level genome assembly for the ecologically and economically important alga Saccharina japonica

Saccharina japonica is a major kelp species of brown algae with the highest production among aquaculture seaweeds and holds important ecological and economic value. Despite advancements in domestication, a high-quality chromosome-level genome assembly is needed to assist its genetic improvement. Previous genome assemblies of S. japonica were either on a draft-level or highly fragmented. Here, we generated a high-quality chromosome-level genome for the female sporophyte using PacBio sequencing and Hi-C. The genome is 516.11 Mb, with contig N50 length of 491.30 Kb and scaffold N50 length of 16.24 Mb, anchored into 32 pseudo-chromosomes. Repetitive elements constituted 45.07% of the genome, and 17,739 protein-coding genes were predicted, of which 82% were functionally annotated. This genome provides a crucial resource for biotechnological advances in S. japonica breeding and offers insights into the ecology and evolution of brown algae.