Chromosome scale assembly unveils genomic structure and gene families of Calotropis procera.

Calotropis procera (Akra, 2n = 22) is a fast-growing, fiber-producing, and climate-resilient, yet underexplored for domestication. The significant step forward in the domestication of this invaluable plant species marks the development of a reference genome. The study reveals a chromosome-scale genome that anchors 11 chromosomes, with a reference assembly spanning approximately 202.83 Mb. It contains few repetitive sequences, accounting for only 5% of the total genome. C. procera display a significant pair-orthology dN/dS ratio of nearly 0.2 to 0.25, indicating strong conservation, purifying selection, and resistance to harsh conditions. C. procera experienced phylogenetic relations with familiar sister genera divergent around 38.5 million years ago. The chromosomal structural rearrangement endured alterations throughout divergence due to a synteny interaction with the genomes of A. syriaca. The findings delve into the role of gene families in the adaptive evolutionary processes of C. procera. The study enhanced our comprehension of genome biology, the influence of gene families on adaptation. The genome research is invaluable and will significantly influence the future domestication of C. procera.