Tagetes erecta cultivar:V-01 Genome sequencing

Marigold (Tagetes erecta L.) is a widely grown ornamental plant and is also the main source of the carotenoid lutein for the industrial production of pharmaceuticals, food coloring, and feed additives. Here, we completed chromosome-scale assembly of the marigold genome, based on Illumina, PacBio, and Hi-C reads. The 707.21 Mb of assembled genome consisted of 35,834 annotated protein-coding genes, with 97.7% genomic integrity. We anchored 87.8% of the contigs (621.20 Mb) to 12 pseudo-chromosomes, bringing the scaffold N50 length to 54.15 Mb. Phylogenetic analysis showed that marigold is relatively closely related to mile-a-minute (Mikania micrantha) and sunflower (Helianthus annuus), all three of which originated in the Americas. Marigold diverged from the sunflower clade around 23.57 million years ago (MYA) and from M. micrantha 19.59 MYA. Compared with M. micrantha and H. annuus, the gene families of marigold are significantly less expanded, and its genome contains significantly fewer interspersed repeats, which might account for its smaller genome. In addition, we identified a range of candidate genes involved in the lutein biosynthetic pathway. The high-quality and accurate reference genome obtained in this study provides a valuable genomic resource for studying the evolution of the Asteraceae family and for improving marigold breeding strategies.