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Whole genome sequencing techniques are capable of providing insights into plant genetic adaptation to climate oscillations. Acer truncatum Bunge is a new resource tree for food with ornamental, timber and medicinal value. However, it has been listed as a near-threatened species because of the decreasing number of natural populations. In order to develop conservation strategies and sustainable innovative utilization for genetic resources, spatial pattern of genetic diversity and demographic history of A. truncatum from 13 natural populations, which cover the entire range, were analyzed by 9,086,353 single nucleotide polymorphisms (SNPs) through whole genome resequencing. The genetic diversity of natural populations was high (He = 0.289, I = 0.449), and genetic variations mainly resided within populations (82.47%) by AMOVA analysis. Cluster analysis showed that 13 natural populations mainly originated from three common gene pools. Therefore, it is recommended that the natural populations (LBGM, BTM, WLS and DQT) with high genetic diversity in different groups were given priority for in situ conservation and the genetic resources from these populations were collected for ex situ conservation. The effective population size of A. truncatum experienced two large-scale sharp contractions and currently decreased to its bottom in history. Nonetheless, A. truncatum could have expanded its effective population size to its historical peak after the last glacial period, indicating that it is highly resilient to fluctuations of temperature and humidity.

Acer sutchuenense subsp. tienchuanenge (Sapindaceae: Acer) is an endangered deciduous arbor species and endemic to China. Being obtained by using genome Illumina pair-end sequencing data, the complete chloroplast genome of A. sutchuenense subsp. tienchuanenge had a typical quadripartite structure, with 156,063 bp long, including a large single-copy (LSC) region of 85,772 bp, a small single-copy (SSC) region of 18,117 bp, and a pair of inverted repeats (IRs) (each 26,087 bp in length). A total of 136 genes were annotated, of which 113 are unique genes, including 30 tRNAs, 4 rRNAs, and 79 protein-coding genes. The overall GC content was 37.9%. The phylogenetic analysis suggested that A. sutchuenense subsp. tienchuanenge was the most closely related to A. griseum and A. triflorum. The complete chloroplast genome of A. sutchuenense subsp. tienchuanenge is valuable for assessment and conservation of genetic resources and further for phylogenetic study of Acer L.

Acer nikoense (Sapindaceae: Acer) is a deciduous tree, belonging to the Ser. Grisea of Sect. Trifoliata. Its complete genome sequence was obtained using genome Illumina pair-end sequencing data. It had a typical quadripartite structure with 155,952 bp in length, consisting of a large single-copy region (85,720 bp) and a small single-copy region (18,072 bp), as well as a pair of inverted repeats (26,080 bp). The total GC content was 37.9%. A total of 113 unique genes were annotated, including 30 tRNAs, 4 rRNAs, and 79 protein-coding genes. The phylogenetic analysis indicated that A. nikoense and A. triflorum were the most closely related.

Acer triflorum (Sapindaceae: Acer) is a deciduous arbor species with excellent ornamental values because of its reddish-tan exfoliating bark and attractive three leaflets. However, due to some wild populations being threatened by poor seed viability, it was listed as vulunerable in China. Its complete chloroplast (cp) genome was obtained using genome Illumina pair-end sequencing data. The cp genome was 156,024 bp in length with a typical circular structure, containing a large single copy (LSC) region of 85,815 bp and a small single copy (SSC) region of 18,051 bp, which were separated by a pair of inverted repeats (IRs) (26,079 bp). A total of 136 genes were annotated, including 88 protein-coding genes, 40 tRNAs and 8 rRNAs. The overall GC content was 37.9%. The phylogenetic analysis suggested that A. triflorum was the most closely related to A. griseum. The complete chloroplast genome of A. triflorum is useful for assessment of genetic diversity and further for taxonomic study of Acer L.