Abstract
Quercus mongolica (Fagaceae) is an important ecological and economic
tree species in East Asia. It has excellent biological characteristics,
such as hardwood, strong resistance to biotic and abiotic stresses. The
availability of a high-quality genome will help to further reveal the
underlying mechanisms. Here we assemble the first chromosome-level
reference genome of Q. mongolica. The final assembled genome was 809.84
Mb with contig and scaffold N50s of 2.64 Mb and 66.74 Mb, respectively.
Hi-C scaffolding anchored twelve pseudochromosomes, accounting for
95.65% of the assembled genome. Moreover, 68.5% and 5.4% of the
genomic sequence were transposon elements and tandem repeat elements,
respectively. A total of 36,553 protein‐coding genes were predicted, of
which 94.89% were functionally annotated. Comparative genomics analysis
indicated that Q. mongolica was more closely related to Q. robur than to
either Q. lobata or Q. suber. Q. mongolica and Q. robur diverged
~10.2 Mya. Q. mongolica had undergone two whole-genome
duplications which occurred earlier than Q. robur. We identified
multiple genes in 38 positive selection genes, including pyridoxal
reductase 1 (PLR1) and switch subunit 3 (SWI3B). In addition, we
identified 496 genes related to wood formation, 88 WRKY genes, and 124
NAC genes in Q. mongolica. This genomic information will be an important
molecular resource for further exploring the biological characteristics
and adaptive evolution of Q. mongolica. Meanwhile, the genomic resource
from Asian oak will also contribute to the study of the taxonomy,
evolution and conservation of Quercus species.