Genome sequencing of four culinary herbs reveals terpenoid genes underlying chemodiversity in the Nepetoideae

Species within the mint family, Lamiaceae, are widely used for their
culinary, cultural, and medicinal properties due to production of a wide
variety of specialized metabolites, especially terpenoids. To further our
understanding of genome diversity in the Lamiaceae and to provide a
resource for mining biochemical pathways, we generated high-quality genome
assemblies of four economically important culinary herbs, namely, sweet
basil (Ocimum basilicum L.), sweet marjoram (Origanum majorana L.),
oregano (Origanum vulgare L.), and rosemary (Rosmarinus officinalis L.),
and characterized their terpenoid diversity through metabolite profiling
and genomic analyses. A total 25 monoterpenes and 11 sesquiterpenes were
identified in leaf tissue from the four species. Genes encoding enzymes
responsible for the biosynthesis of precursors for mono- and
sesqui-terpene synthases were identified in all four species. Across all
four species, a total of 235 terpene synthases were identified, ranging
from 27 in O. majorana to 137 in the tetraploid O. basilicum. This study
provides valuable resources for further investigation of the genetic basis
of chemodiversity in these important culinary herbs.