Populus has a wide ecogeographical range spanning the Northern
Hemisphere, and exhibits abundant distinct species and hybrids globally.
Populus tomentosa Carr. is widely distributed and cultivated in
the eastern region of Asia, where it plays multiple important roles in
forestry, agriculture, conservation, and urban horticulture. Reference
genomes are available for several Populus species, however, our
goals were to produce a very high quality de novo, chromosome-level
genome assembly in P. tomentosa genome that could serve as a
reference for evolutionary and ecological studies of hybrid speciation.
Here, combining long-read sequencing and Hi-C scaffolding, we present a
high-quality, haplotype-resolved genome assembly. The genome size was
740.2 Mb, with a contig N50 size of 5.47 Mb and a scaffold N50 size of
46.68 Mb, consisting of 38 chromosomes, as expected with the known
diploid chromosome number (2n=2x=38). A total of 59,124 protein-coding
genes were identified. Phylogenomic analyses revealed that P.
tomentosa is comprised of two distinct subgenomes, which we
deomonstrate is likely to have resulted from hybridization between
Populus adenopoda as the female parent and Populus alba
var. pyramidalis as the male parent, approximately 3.93 Mya.
Although highly colinear, significant structural variation was also
found between the two subgenomes. Our study provides a valuable resource
for ecological genetics and forest biotechnology.