A haplotype-resolved genome assembly and gene expression map of Cushion willow.

Salix brachista, commonly known as Cushion willow, is a common component of subnival alpine assemblages and a dioecious or monoecious plant with a creeping stem and numerous lateral branches. Cushion willow takes cuttings more easier and has a specific sex system, making it a suitable system for studying the evolution of plant sex determination, adaptive evolution of alpine plants, and mining stress resistance gene resource that cope with the hostile alpine environment. Therefore, Cushion willow has potential value in genetic improvements for willows used as bioenergy crops, in gardening, and as ornamental plants. However, the genome of Cushion willow still contains some un-assembled repetitive sequences, and there is limited availability of a gene expression atlas, which hinders its potential use for the aforementioned purposes. Here, we updated the genome of Cushion willow to be haplotype-resolved and near telomere-to-telomere, and obtained a high-quality transcriptomic map. Our research provides a potential model species for alpine adaptive research, sex determination evolution studies, and improving willow crops.