Transcriptome analysis in the pulp of ‘Saijo’ persimmon during storage at low temperature

‘Saijo’ persimmon is a popular semi-dried, also known as “Anpo-kaki”, and/or de-astringent-treated fruit. Before semi-drying or after the astringency removal treatment, it is desirable for the persimmon fruit to maintain its high quality under low temperature to extend its shelf life. To elucidate the transcriptomic changes in persimmon ‘Saijo’ fruit during storage at low temperatures, we conducted RNA-sequencing analysis of the inner and outer pulps of de-astringent-treated fruit stored at 2°C for 0 (immediately after removal of astringency treatment) and 14 days. Fruit softening occurred during the 14 days of cold storage. In all the pulps tested, cold stress response genes, such as those coding the heat shock and late embryogenesis abundant proteins, were upregulated. In terms of cell wall-degrading related enzymes, polygalacturonase, pectin methylesterase, pectin acetylesterase, xyloglucan endotransglucosylase/hydrolase, and expansin were downregulated in the outer and inner pulps of de-astringent-treated fruit. Only β-galactosidase was upregulated in the pulp at low temperature. This study provides an initial overview of a set of genes that are expressed during storage at low temperatures in persimmon fruit.