High-quality genome assembly of Cinnamomum burmannii (chvar. Borneol)
provides insights into phylogenetic relationship within Cinnamomum and
natural borneol biosynthesis
Abstract
Cinnamomum burmannii is an important medicinal and industrial plant as
its key source for natural borneol (D-borneol), one of the precious
materials and widely used in the pharmaceutical and cosmetic industries.
Here, we report a high-quality chromosome-scale genome assembly of Mei
Pian Tree (C. burmannii (chvar. Borneol)), a chemotype of C. burmannii
containing high content of natural borneol. The assembled genome size
was 1.14 GB with a scaffold N50 of 94.30 Mb, while 98.77% of the
assembled sequences were anchored on 12 pseudochromosomes including
41549 protein-coding genes. Comparative genomic analysis revealed C.
burmannii and C. micranthum,shared two Lauraceae unique ancestral
whole-genome duplication (WGD) events, and strong collinearity was
detected between these two species. The analysis for repetitive sequence
indicated the outbreak of LTR-RTs insertion made a great contribution to
the size difference of genomes between C. burmannii and C. micranthum.
Pathways and transcriptome analysis demonstrated differential expression
of genes involve in MEP may be the main factors for D-Borneol production
differences between the two chemotypes (chvar. Borneol/Wild). We also
identified and their differential expressions were further analyzed in
various biological tissues. Finally, we constructed the genome database
(CAMD; http://www.cinnamomumdatabase.com/) of Cinnamomum species. The
present study provided the first high quality genome of C. burmannii and
comprehensive analysis of the biosynthesis pathway of natural borneol.
We also provided novel insights into the molecular basic for chemotypes.
These results will shed light on the understanding of the evolution of
Lauraceae plants and genetic improvement of this commercially important
plant.