Carnation (Dianthus caryophyllus) is a perennial plant within the family Caryophyllaceae and the genus Dianthus. As one of the “world's four major cut flowers”, it has high ornamental and economic value.

Prof. Fu Xiaopeng’s team from the College of Horticulture & Forestry Sciences of HZAU, together with the research fellow Wu Zhiqiang’s team from the Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, for the first time assembled a high-quality Chromosome-scale genome of D.caryophyllus. Then they systematically studied the evolution of the carnation genome and analyzed the molecular mechanism of ornamental traits of carnation flowers such as petal coloration, double flowers, and fragrance production. And the gene regulators of important ornamental traits were identified. The article about the research finding was published on Plant Biotechnology Journal.

Using ONT III (Oxford Nanopore Technologies), Illumina II and HIC techniques, the research team sequenced and assembled the whole genome of the D. caryophyllus cultivar, the “Scarlet Queen”. In the final 636.30Mb genome assembly, the repeat sequences accounted for 70.62%. A total of 43,925 protein-coding genes were predicted. The divergence time of the carnation and Chenopodiaceae was estimated at ~ 64 million years ago. And a whole-genome polyploidy event occurred recently, which triggered the expansion of genes related to eugenol synthesis. Eugenol is often referred to as a characteristic aroma of carnations.

Based on this genome, the team conducted metabolomic analysis on the carnation petals with red margins and found that the accumulation of pelargonidin was responsible for the red coloration of petal margins. And the accumulation of lutein and multiple flavonoids contributed to the yellow coloration of petal limbs. Moreover, by combining with transcriptome data, several genes that jointly regulate the formation of multicolor were identified.

At the same time, the team parsed the accumulation of eugenol in flowers at various stages and found that EGS (eugenol synthase) genes had structural change in exons, whose premature stop may explain the lack of eugenol in carnation. Within context of the ABC model for flower development, the ectopic expression of class A genes (which determine sepals) and class C genes (which determine carpel formation) in carnation may be an important factor for the formation of double-flower carnation.

This study provides high-quality genomic resources needed to develop improved and novel ornamental traits in carnations.

The source of the relevant article: https://doi.org/10.1111/pbi.13801

Source: http://news.hzau.edu.cn/2022/0310/62725.shtml

Translated by: Wang Yuyan

Supervised by: Guo Haiyan