A haplotype-phased male genome sequence of the stinging nettle, Urtica dioica ssp. dioica

Stinging nettle (Urtica dioica L.) is a widespread weed of economic significance with a dioecious mating system. Previously, we generated a high-quality genome assembly of a diploid female plant, which showed extreme levels of structural variation between haplotypes. Here, we present a chromosome-level, haplotype-resolved sequence of a diploid male plant; since the male is believed to be the heterogametic sex in Urtica dioica, this assembly represents a first step towards elucidating the control of sex determination in this species. This completely independently assembled genome also allows confirmation of previously reported features of the nettle genome, including (1) a high degree of structural variation between haplotypes, including large inversions, (2) the likely existence of polycentric centromeres, and (3) the presence of urticaceous "pain peptide" sequences. Chromosome 8 stands out for its multiple large, nested inversions and high levels of repetitive sequences, features that are often associated with sex determining regions (SDRs). This chromosome is therefore a candidate for further investigations to characterize the sex determination in nettle.