Transcriptome analysis of astringent 'Cheongdo-Bansi' persimmon fruit treated with ethylene for removal of astringency

This research was conducted to study the gene expression related to the removal of astringency and ripening in astringent `Cheongdo-Bansi' persimmon. Fruit treated with ethylene were used to compare the differentially expressed genes against fruit ripened naturally without ethylene treatment (control). We sequenced total mRNAs using Illumina high-throughput sequencing platform and constructed the transcriptome gene set by de novo assembly. We identified 93,601 unigenes with an average length of 643.2 bp in transcriptome contigs. Differential gene expression analysis was performed and a total of 12,374 unigenes were differentially expressed in the ethylene vs. control. Of these 12,374 unigenes, 6072 were up-regulated and 6302 were down-regulated in the treated fruit. Compared with the control, the number of genes that induced more than 2 fold expression were 2647 and the number of genes whose expression was inhibited more than 2 fold were 2804. We also identified 38 genes showing significantly different expression, 26 of which were up-regulated and the rest 12 genes were down-regulated. The identified genes were categorized as genes related to astringency removal, softening and other ripening-related changes. The present study will add the information on the effect of ethylene treatment for astringency removal, softening and other ripening-related changes of persimmon fruit at genomic level. This study will also contribute important resources for further study of the genes related to astringent substance for persimmon breeding and improvement.