A High-Quality, Chromosome-Level Genome Provides Insights Into Determinate Flowering Time and Color of Cotton Rose (Hibiscus mutabilis)

Abstract

Hibiscus mutabilis (cotton rose) is a deciduous shrub or small tree of the Malvaceae family. Here, we report a chromosome-scale assembly of the H. mutabilis genome based on a combination of single-molecule sequencing and Hi-C technology. We obtained an optimized assembly of 2.68 Gb with a scaffold N50 length of 54.7 Mb. An integrated strategy of homology-based, de novo, and transcriptome-based gene predictions identified 118,222 protein-coding genes. Repetitive DNA sequences made up 58.55% of the genome, and LTR retrotransposons were the most common repetitive sequence type, accounting for 53.15% of the genome. Through the use of Hi-C data, we constructed a chromosome-scale assembly in which Nanopore scaffolds were assembled into 46 pseudomolecule sequences. We identified important genes involved in anthocyanin biosynthesis and documented copy number variation in floral regulators. Phylogenetic analysis indicated that H. mutabilis was closely related to H. syriacus, from which it diverged approximately 15.3 million years ago. The availability of cotton rose genome data increases our understanding of the species’ genetic evolution and will support further biological research and breeding in cotton rose, as well as other Malvaceae species.

The genome of okra (Abelmoschus esculentus) provides insights into its genome evolution and high nutrient content

“…3f , right panel) . Three WGD events have previously been reported in H. mutabilis [ 19 ], and regarding the 4:3 ratio, we speculated that the most recent WGD reported in the H. mutabilis genome was a whole genome triplication (WGT) event that occurred independently after the divergence of okra and H. mutabilis . Fourth, we also calculated the syntenic depth ratio of H. cannabinus vs H. mutabilis , yielding an overall 1:3 pattern ( Fig.…”

“…Additionally, a previous study reported two additional WGD events occurring in the H. mutabilis genome [ 19 ]. Interestingly, our results indicate that the most recent WGD event in H. mutabilis was actually a WGT event ( Fig.…”

“…In addition to okra, the Malvaceae family also harbors many other important species. The genomes of multiple Malvaceae species have been published, mainly from two genera, Gossypium and Hibiscus , including Gossypium raimondii [ 13 ], Gossypium darwinii [ 14 ], Gossypium herbaceum [ 15 ], Gossypium hirsutum [ 16 ], Hibiscus syriacus [ 17 ], Hibiscus cannabinus [ 18 ], Hibiscus mutabilis [ 19 ], and Hibiscus hamabo [ 20 ]. The chromosome numbers in Malvaceae are highly variable [ 21 ], which might reflect the complex evolutionary history of this family.…”

Transcription and Metabolic Profiling Analysis of Three Discolorations in a Day of Hibiscus mutabilis

“…As the city flower of Chengdu, H. mutabilis has important historical, cultural, and ornamental value [ 1 ]. H. mutabilis is popular with tourists because of its variety and ability to change colors over the course of one day.…”

“…Hibiscus mutabilis is an important ornamental plant from the Malvaceae family that originated in China and has been cultivated in China for more than 2000 years [ 1 ]. As an ornamental plant, H. mutabilis has spread to Japan, Korea, and other countries in Asia.…”