Chenopodium berlandieri (pitseed goosefoot) is a widespread native North American plant, which was cultivated and consumed by indigenous peoples prior to the arrival of European colonists.Chenopodium berlandieri is closely related to, and freely hybridizes with the domesticated South American food cropC. quinoa. As such it is a potential source of wild germplasm for breeding withC. quinoa, for improved quinoa production in North America. TheC. berlandieri genome sequence could also be a useful source of information for improving quinoa adaptation. To this end, we first optimized barcode markers in two chloroplast genes,rbcL andmatK. Together these markers can distinguishC. berlandieri from the morphologically similar Eurasian invasiveC. album (lamb's quarters). Second, we performed whole genome sequencing and preliminary assembly of aC. berlandieri accession collected in Manitoba, Canada. Our assembly, while fragmented, is consistent with the expected allotetraploid structure containing diploidChenopodium sub-genomes A and B. The genome of our accession is highly homozygous, with only one variant site per 3-4000 bases in non-repetitive sequences. This is consistent with predominant self-fertilization. As previously reported for the genome of a partly domesticated Mexican accession ofC. berlandieri, our genome assembly is similar to that ofC. quinoa. Somewhat unexpectedly, the genome of our accession had almost as many variant sites when compared to the MexicanC. berlandieri, as compared toC. quinoa. Despite the overall similarity of our genome sequence to that ofC. quinoa, there are differences in genes known to be involved in the domestication or genetics of other food crops. In one example, our genome assembly appears to lack one functional copy of theSOS1 (salt overly sensitive 1) gene.SOS1 is involved in soil salinity tolerance, and by extension may be relevant to the adaptation ofC. berlandieri to the wet climate of the Canadian region where it was collected. Our genome assembly will be a useful tool for the improved cultivation of quinoa in North America.

The authors declare no conflict of interest.