Beech trees of the genus
Fagus (Fagaceae) are monoecious and distributed in the Northern Hemisphere. They represent an important component of mixed broad-leaved evergreen–deciduous forests and are an economically important source of timber. Despite their ecological and economical importance, however, little is known
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Beech trees of the genus
Fagus (Fagaceae) are monoecious and distributed in the Northern Hemisphere. They represent an important component of mixed broad-leaved evergreen–deciduous forests and are an economically important source of timber. Despite their ecological and economical importance, however, little is known regarding the overall plastome evolution among
Fagus species in East Asia. In particular, the taxonomic position and status of
F.
multinervis, a beech species endemic to Ulleung Island of Korea, remains unclear even today. Therefore, in this study, we characterized four newly completed plastomes of East Asian
Fagus species (one accession each of
F.
crenata and
F.
multinervis and two accessions of
F.
japonica). Moreover, we performed phylogenomic analyses comparing these four plastomes with
F. sylvatica (European beech) plastome. The four plastomes were highly conserved, and their size ranged from 158,163 to 158,348 base pair (bp). The overall GC content was 37.1%, and the sequence similarity ranged from 99.8% to 99.99%. Codon usage patterns were similar among species, and 7 of 77 common protein-coding genes were under positive selection. Furthermore, we identified five highly variable hotspot regions of the
Fagus plastomes (
ccsA/
ndhD,
ndhD/psaC,
ndhF/
rpl32,
trnS-GCU/
trnG-UCC, and
ycf1). Phylogenetic analysis revealed the monophyly of
Fagus as well as early divergence of the subgenus
Fagus and monophyletic
Engleriana. Finally, phylogenetic results supported the taxonomic distinction of
F. multinervis from its close relatives
F. engleriana and
F. japonica. However, the sister species and geographic origin of
F. multinervis on Ulleung Island could not be determined.
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