Chromosome-Level Genome Assembly Provides New Insights into Genome Evolution and Tuberous Root Formation of...

Potentilla anserina is a perennial stoloniferous plant with edible tuberous roots in Rosaceae, served as important food and medicine sources for Tibetans in the Qinghai-Tibetan Plateau (QTP), China, over thousands of years. However, a lack of genome information hindered the genetic study. Here, we presented a chromosome-level genome assembly using single-molecule long-read sequencing, and the Hi-C technique. The assembled genome was 454.28 Mb, containing 14 chromosomes, with contig N50 of 2.14 Mb. A total of 46,495 protein-coding genes, 169.74 Mb repeat regions, and 31.76 Kb non-coding RNA were predicted. P. anserina diverged from Potentilla micrantha ∼28.52 million years ago (Mya). Furthermore, P. anserina underwent a recent tetraploidization ∼6.4 Mya. The species-specific genes were enriched in Starch and sucrose metabolism and Galactose metabolism pathways. We identified the sub-genome structures of P. anserina, with A sub-genome was larger than B sub-genome and closer to P. micrantha phylogenetically. Despite lacking significant genome-wide expression dominance, the A sub-genome had higher homoeologous gene expression in shoot apical meristem, flower and tuberous root. The resistance genes was contracted in P. anserina genome. Key genes involved in starch biosynthesis were expanded and highly expressed in tuberous roots, which probably drives the tuber formation. The genomics and transcriptomics data generated in this study advance our understanding of the genomic landscape of P. anserina, and will accelerate genetic studies and breeding programs.