Genomic Study of Gypsophila paniculata

Gypsophila paniculata, belonging to the Caryophyllaceae of the Caryophyllales, is one of the famous cut flowers widely used in daily life throughout the world. It is commonly used as the dried flower, whereas the underlying mechanisms such as flower senescence are unaddressed. Here, we present a chromosome-scale genome assembly for G. paniculata with a total size of 749.58 Mb. Whole- genome duplication signatures unveil two major duplication events in its evolutionary history, an ancient one occurring before the divergence of Caryophyllaceae and a more recent one shared with Dianthus caryophyllus. The integrative analyses combining genomic and transcriptomic data reveal the mechanism regulating floral development and ethylene response of G. paniculata. The loss-of- function of AGAMOUS and miR172-mediated APETALA2/PETALOSA expression are associated with double flower formation in G. paniculata. The low expression of ERS (ETHYLENE RESPONSE SENSOR) and the reduction of downstream ERF (ETHYLENE RESPONSE FACTOR) gene copy number collectively lead to the ethylene insensitivity of G. paniculata, affecting flower senescence and making it capable of making dried flowers. This study provides a cornerstone for understanding the underlying principles governing floral development and dried flower, which could accelerate the molecular breeding of the Caryophyllaceae species.