Overview

The chrysanthemum genome project was conducted through the National Agricultural Genome Program (NAGP) and National Institute of Agricultural Sciences (NAS) Program, Republic of Korea.

Chrysanthemum boreale (Asteraceae;Asteroideae;Anthemideae) is a perennial plant native to Eastern Asia and has been used for ornamental and herbal purposes. C. boreale is a diploid species (2n=2x=18) and is close to the commercial and cultivated species, Chrysanthemum morifolium with a large and hexaploid genome (2n=6x=54). Therefore, C. boreale is used as a model plant in the study of cultivated chrysanthemum.

The genome was sequenced using PacBio single-molecule real-time long reads and was scaffolded into nine chromosome sequences using the Bionano optical map and the Hi-C contact map. Genome coverage is high according to the mapping rate of Illumina short reads and BUSCO analysis, although the Bionano optical map resulted in large gap during scaffolding process as shown in the total length of contigs 3.415 Gb and scaffolds 5.524 Gb. The assembled genome corresponds to the original sequences including large gap and the sequence tag (CTTAAG) generated from Bionano map. Considering this, below statistics was calculated in two ways without and with gap.

Statistics

Genome

Approximately 3.237 Gb is assembled in 9 chromosomes, with 0.181 Gb of unmapped scaffolds (w/o gap).

Approximately 4.831 Gb is assembled in 9 chromosomes, with 0.692 Gb of unmapped scaffolds (with gap).

Scaffold N50 = 379 Mb, Longest scaffold = 401 Mb (w/o gap)

Scaffold N50 = 557 Mb, Longest scaffold = 610 Mb (with gap)

Contig N50 = 218 kb, longest contig = 3.232 Mb

Organelle genome

The complete chloroplast genome is 151,012 bp in size (NCBI ID MG913594) and harbors 114 unique genes including 80 protein-coding genes, 4 rRNA gene, and 30 tRNA genes. The complete mitochondrial genome is 211,002 bp in size (NCBI ID MH004292) and harbors 58 genes including 35 protein-coding genes, 3 rRNA genes, and 20 tRNA genes.

References

So Youn Won, Jae-A Jung, and Jung Sun Kim (2018) The complete chloroplast genome of Chrysanthemum boreale (Asteraceae). Mitochondrial DNA Part B: Resources 3:549-550.

So Youn Won, Jae-A Jung, and Jung Sun Kim (2018)The complete mitochondrial genome sequence of Chrysanthemum boreale (Asteraceae). Mitochondrial DNA Part B: Resources 3:529-530.