Draft Genome of Tanacetum Coccineum: Genomic Comparison of Closely Related Tanacetum-Family Plants.

The plant (painted daisy) is closely related to (pyrethrum daisy). However, produces large amounts of pyrethrins, a class of natural insecticides, whereas produces much smaller amounts of these compounds. Thus, comparative genomic analysis is expected to contribute a great deal to investigating the differences in biological defense systems, including pyrethrin biosynthesis. Here, we elucidated the 9.4 Gb draft genome of , consisting of 2,836,647 scaffolds and 103,680 genes. Comparative analyses of the draft genome of and that of , generated in our previous study, revealed distinct features of genes. While the genome contains more numerous ribosome-inactivating protein (RIP)-encoding genes, the number of higher-toxicity type-II RIP-encoding genes is larger in . Furthermore, the number of histidine kinases encoded by the genome is smaller than that of , suggesting a biological correlation with pyrethrin biosynthesis. Moreover, the flanking regions of pyrethrin biosynthesis-related genes are also distinct between these two plants. These results provide clues to the elucidation of species-specific biodefense systems, including the regulatory mechanisms underlying pyrethrin production.