First whole genome sequence of a diploid crop wild relative of the Andean tuber “oca”: Annotation and comparative genomic analysis of  <i>Oxalis oulophora</i>

Oxalis oulophora, a diploid species closely related to the octoploid Andean tuber crop oca (Oxalis tuberosa), was selected for whole-genome sequencing to aid in understanding the origins of polyploidy and domestication in oca and its relatives (crop wild relatives). The Oxalis tuberosa alliance, a monophyletic clade consisting of morphologically similar species to oca, encompasses multiple cytotypes ranging from diploids to octoploids and is notable for its cytogenetic complexity and its economic importance as a source of cultivated edible tubers. Oca is an important crop in the central Andes, second only to potatoes, and its genetic history remains largely unresolved. As the first draft genome within the alliance clade, O. oulophora serves as a crucial reference for investigating genome evolution and polyploidization events in this group. Using PacBio HiFi reads, we generated a high-quality assembly with an estimated genome size of 473.42 Mb and 50.4× coverage. The assembly consists of 502 contigs, with the largest contig measuring 53.75 Mb, an N50 of 34.49 Mb, and an N75 of 10.44 Mb. Gene prediction identified 31,221 protein-coding genes, of which 27,362 were successfully annotated. This draft genome provides a valuable foundation for phasing polyploid genome assemblies and deciphering the evolutionary history of O. tuberosa and other tuber-bearing Oxalis species. The data will facilitate future research on genome evolution, domestication, and adaptation in polyploid crops, contributing to broader studies of plant polyploidy and agricultural biodiversity.