The Characteristics of Carotenoid Accumulation and Expression of Carotenoid Biosynthetic Genes in the Japanese Persimmon ‘Soshu’ and ‘Tonewase’ Fruits

‘Soshu’ and ‘Tonewase’ are major early maturing varieties of Japanese persimmon (Diospyros kaki Thunb.). The skin of ‘Soshu’ is red, whereas the color of ‘Tonewase’ is orange at harvest. In the present study, we investigated carotenoid accumulation in fruits of these two persimmon varieties. In the fruit skin, the levels of expression of carotenoid biosynthetic genes except for lycopene-ε-cyclase increased with carotenoid accumulation during fruit maturation. In ‘Soshu’, a large accumulation of carotenoids was observed at harvest. The total carotenoid content in ‘Soshu’ was nearly twice as high as that in ‘Tonewase’. Both varieties predominantly accumulated β-carotene, zeaxanthin, and β-cryptoxanthin, accounting for nearly 90% of the total carotenoids. The composition of carotenoids in ‘Soshu’ was similar to that in ‘Tonewase’. In the flesh, the level of expression of carotenoid biosynthetic genes except for lycopene-ε-cyclase and zeaxanthin epoxidase increased with carotenoid accumulation during fruit maturation. The total carotenoid content in ‘Soshu’ was nearly four times as high as that in ‘Tonewase’. The composition of carotenoids in ‘Soshu’ was similar to that in ‘Tonewase’.