Physiological, biochemical and transcriptomic analyses reveal the mechanism of variation in color traits in Panax japonicus fruits

Panax japonicus C. A. Mey. is a rare and endangered Class II important protected wild medicinal plant in China with a wide range of pharmacological activities. The development of the fruit is special, only the apical capitulum can develop into fruit normally, and the colour trait changes during the maturation process showed a pattern from green to red and from red to purple-black. Overall design: In order to reveal the phenomenon of colour trait changes during fruit development, this paper analyzed the correlation between colour trait changes and pigment contents (chlorophyll, carotenoids) and secondary metabolite contents (anthocyanosides, flavonoids, and total phenols) of the fruits, and used transcriptome sequencing to explore the correlation between colour trait changes and synthetic genes, and then verified the fluorescence quantification with qRT-PCR. Transcriptome sequencing obtained transcriptome data of 15 samples from five periods of colour trait changes in Panax japonicus fruits