Abstract
To investigate characteristics of carotenoid biosynthesis in the Japanese persimmon ‘Fuyu’ fruit during maturation, carotenoids and gene expression for phytoene synthase (DK-PSY), phytoene desaturase (DK-PDS), ζ-carotene desaturase (DK-ZDS), lycopene β-cyclase (DK-LCYb), β-ring hydroxylase (DK-HYb), zeaxanthin epoxidase (DK-ZDS) and lycopene ε-cyclase (DK-LCYe) were analyzed. In the skin, lutein was the main carotenoid at the green stage. The level of gene expression of DK-LCYe was constant throughout the experimental period. In contrast, the level of carotenoid-biosynthetic enzymes with the exception of DK-LCYe was lower in the green stage than in the coloring stage. These findings suggested that during the green stage, DK-LCYe played an important role in carotenoid biosynthesis and was responsible for massive accumulation of lutein. In the coloring stage after October, β-cryptoxanthin (β-CRY) and zeaxanthin were mainly accumulated. At this stage, simultaneous increase of the gene expression for carotenoid-biosynthetic enzymes with the exception of DK-LCYe was observed. It was thought that the change in expression profile of the genes accelerated the accumulation of β-CRY and zeaxanthin in this stage. In the flesh, β-CRY and zeaxanthin were mainly accumulated in October. Lycopene was mainly accumulated in November. The lycopene accumulation was accompanied by a massive increase in expression of genes at the later stages of lycopene biosynthesis (DK-PSY, DK-PDS and DK-ZDS). This finding suggested that lycopene accumulation was caused by massive increase in the expression of genes at the later stages of lycopene biosynthesis.
