Novel production of β-cryptoxanthin in haskap (Lonicera caerulea subsp. edulis) hybrids: Improvement of carotenoid biosynthesis by interspecific hybridization

Carotenoids are important color pigments that contribute to human health. Haskap (Lonicera caerulea subsp. edulis), a shrub mainly distributed in Hokkaido, produces violet-blue berries low in carotenoid amount. We have conducted interspecific hybridization between Miyama-uguisukagura (Lonicera gracilipes var. glandulosa) and haskap to obtain interspecific hybrids for improving fruit quality. In this study, we compared four carotenoid concentrations in fruits using liquid chromatography/tandem mass spectrometry (LC/MS/MS) to reveal carot-enoid accumulation changes by interspecific hybridization. beta-Carotene was the main carotenoid, and the con-centration in interspecific hybrids (0.49-0.77 mg/100 g FW) was higher than Miyama-uguisukagura (0.37 mg/ 100 g FW) and haskap (0.25-0.35 mg/100 g FW). beta-Cryptoxanthin concentration was below the quantification limit in haskap strains; however, we could quantify beta-cryptoxanthin in interspecific hybrids. beta-Cryptoxanthin concentration in Miyama-uguisukagura fruits and the interspecific hybrid strain that contained higher beta-cryp-toxanthin tended to increase during maturation, although others did not increase. Our study revealed that interspecific hybridization changed carotenoid biosynthesis, increased beta-carotene, and induced the conversion of beta-cryptoxanthin to haskap. This study proposes a strategy to expand color variation by interspecific hybridization in fruit breeding programs and provides novel materials to analyze the "vigor" phenomenon in hybrid plants.