Trifolium pratense L. Genome sequencing and assembly

Red clover (Trifolium pratense L.) is a perennial leguminous plant with high nutritional value and yield. It is used as green manure and temporary mulch and occupies an important position asa forage grass and high-quality feed for livestock. Moreover, it is of great significance for the sustainable development of animal husbandry. Consequently, a high-quality genome assembly of red clover is essential for selecting and breeding new varieties. At present, the chromosome-level reference genome has a size of 309 Mb and a scaffold N50 size of 223 kb. In total, 40868 genes and 42223 transcripts have been annotated. In this study, we show a de novo genome assembly of red clover at the chromosome level with a size of 423 Mb and a scaffold N50 size of 55 Mb. We located 97.32% (412 Mb)of the sequence toseven chromosomes and annotated 44588 genes and 46089 transcripts. Thus, the assembly quality has been dramatically improved compared to the previously published red clover genome. With this high-quality de novo genome assembly of red clover at the chromosome level, we provide a high-level reference genome for Trifolium plants and even legumes. Ultimately, our research provides a valuablesource for future genomics research of biological and agronomic traits of forage crops.