Chromosome-scale genome assembly for Yellow Wood sorrel,Oxalis stricta

Yellow wood sorrel (Oxalis strictaL.), also known as sourgrass, juicy fruit, or sheep weed, is a member of the Oxalidaceae family. Yellow wood sorrel is commonly considered a weed and while native to North America, it is distributed across Europe, Asia, and Africa. To date, only two other genomes from the Oxalidaceae family have been published, star fruit (Averrhoa carambolaL.) andOxalis articulataSavingy. Here, we present a chromosome-scale assembly forO. stricta, revealing its allotetraploid nature and synteny within its two subgenomes as well as synteny withA. carambolaandO. articulata. Using Oxford Nanopore Technologies long-read sequences coupled with chromatin capture sequencing, we generated a 436 Mb chromosome-scale assembly ofO. strictawith a scaffold N50 length of 36.2 Mb that is anchored to 12 chromosomes across the two subgenomes. Assessment of the final genome assembly using the Long Terminal Repeat Assembly Index yielded a score of 13.12 and assessment of Benchmarking Universal Single Copy Orthologs revealed 99.3% complete orthologs; both metrics are suggestive of a high-quality reference genome. Total repetitive sequence content in theO. strictagenome was 39.7% with retroelements being the largest class of transposable elements. Annotation of protein-coding genes yielded 61,550 high confidence genes encoding 115,089 gene models. Synteny between the twoO. strictasubgenomes was present in 91 syntenic blocks containing 40,705 genes, of which, 76.6% were present in 1:1 syntenic relationships between the two subgenomes. The availability of an annotated chromosome-scale high quality genome assembly forO. strictawill provide a launching point to understand the high fecundity of this weed and provide further foundation for comparative genomics within the Oxalidaceae.