The Accumulation of Crocin and Geniposide and Transcripts of Phytoene Synthase during Maturation of Gardenia jasminoides Fruit

Gardenia fruit (fruit of Gardenia jasminoides Ellis) is used as a natural pigment resource and a Chinese traditional medicine. The white mesocarp turning orange or red that occurs during gardenia fruit maturation arises from the production and accumulation of the apocarotenoids, especially crocin-1, which is derived from carotenoid. Meanwhile, the major medical component geniposide is accumulated in gardenia fruit. To further our understanding of the synthetic and accumulation mechanism for crocin-1 and geniposide in gardenia fruit, the contents of crocin-1 and geniposide and the transcripts of phytoene synthase (GjPSY) profiles in gardenia fruits were examined at various stages of maturation. The concentration of crocin-1 and geniposide in gardenia fruit was determined by reversed-phase high-performance liquid chromatography (HPLC). The results showed that the concentration of crocetin-1 was increased during fruit development and the concentration of geniposide does not change significantly during maturing. The expression levels of GjPSY mRNA were examined by RT-PCR. It was revealed that GjPSY was constitutively expressed during fruit development, suggesting that the primary mechanism that controls crocin accumulation in G. jasminoides fruits during development is not correlated to the differential regulation of transcript levels of GjPSY gene.