Carotenoid levels in fruit change dynamically in response to storage condition, however, the underlying mechanism remains unclear.
"We have investigated the carotenoid profiles and have associated gene expression to reveal its responses to different storage temperature (20 °C and 4 °C) in two kiwifruit cultivars, bright-yellow-fleshed Jinshi 1 and pale-yellow-fleshed Jinyan" say the scientists at Sichuan Agricultural University (Chengdu, China).
At harvest, four main carotenoids were detected in cv. Jinshi 1, while only three in cv. Jinyan, excluding β-cryptoxanthin, which accounted for the majority of carotenoids in Jinshi 1. Results showed that storage at 20°C increased content of the total carotenoid and β-carotene in both cultivars, and up-regulated the expression of biosynthesis gene PSY, but down-regulated the expression of carotenoid degradation genes CCD1 and NCED1. It also induced β-cryptoxanthin and α-carotene production in Jinyan at later stage. On the contrary, storage at 4 °C decreased total carotenoid content, but induced the expression of carotenoid biosynthetic gene PDS, LCYB, LCYE.
"Results have demonstrated that the increase in carotenoids level at 20°C depends on PSY, CCD1 and NCED1 genes - the scientists conclude - Furthermore, a high proportion of β-cryptoxanthin might contribute to yellower flesh in Jinshi 1".
Source: Hui Xia, Xiu Wang, Wenyue Su, Liujing Jiang, Lijin Lin, Qunxian Deng, Jin Wang, Honghong Deng, Rongping Hu, Mingan Liao, Xiulan Lv, Dong Liang, 'Changes in the carotenoids profile of two yellow-fleshed kiwifruit cultivars during storage', 2020, Postharvest Biology and Technology, Volume 164, 111162.