Anthocyanin accumulation in the flesh of ‘Ruby Sweet’ and ‘Rose Pearl’ apples during cold storage

The red coloration of the flesh of red-fleshed apples is due to anthocyanin accumulation. ‘Ruby Sweet’ and ‘Rose Pearl’ are red-fleshed apple cultivars that were released in Japan in 2015. However, ‘Ruby Sweet’ apples often lack red coloration in their flesh.
The cause of the variation in anthocyanin accumulation in the flesh is unknown.
We found that anthocyanin in the flesh of some ‘Ruby Sweet’ apples significantly increased within two weeks of cold storage in the 2015 season and that anthocyanin accumulation and ethylene production were partially suppressed by 1-methylcyclopropene (MCP) application.
These results indicate that ethylene action promotes anthocyanin synthesis in the flesh during cold storage.
We thought that the lack of anthocyanins might be compensated for by cold storage and conducted cold storage experiments on ‘Ruby Sweet’ and ‘Rose Pearl’ apples from 2017 to 2019. Unfortunately, no notable increase in anthocyanin content during cold storage (6-8 weeks) was observed for either cultivar in any of the years.
The cause of the increase or lack of increase in anthocyanin in the fruit flesh during cold storage was not clear.
RT-PCR experiments showed that the expression of anthocyanin biosynthetic genes encoding chalcone synthase (CHS) and anthocyanin synthase (ANS) in the fruit flesh was maintained to some extent during cold storage, indicating that the anthocyanin biosynthetic genes in the fruit flesh continued to be expressed under low-temperature conditions without light.

IV Asian Horticultural Congress – AHC2023

C. Honda, R. Fujiwara, K. Okada, M. Tatsuki, H. Iwanami

anthocyanin, apple, ethylene, flesh, cold storage

https://doi.org/10.17660/ActaHortic.2024.1404.110