Molecular analysis of the mechanisms for controlling tannin accumulation of pollination-constant nonastringent (PCNA)-type persimmons in Chinese and Japanese cultivars to clarify different origins between them.

点击翻译按钮获取中文摘要

The analysis was performed to identify key genes for regulating tannin accumulation into fruits of pollination constant non-astringent (PCNA)-type of persimmon originated in Japan and China. For this purpose, we conducted the following three experiments:1)We constructed genomic library from closely related diploid species, D. lotus, and a seed clone was screened from the library with a probe tightly linked to the trait of natural astringency-loss of Japanese-type PCNA fruits. Then, we constructed ca. 300 kbp contig of D. lotus. Due to the sequence analysis of this contig, we found that the sequences are very homologous to those of D. kaki and it can use for exploring the gene of persimmon (D. kaki). In addition, primer sets designed from the sequences of this contig were able to be applicable to distinguish Japanese-type PCNA from others. We could make a universal primer set to select PCNA persimmon.2)We conducted the expression analysis of mRNA to identify the genes involved in tannin accumulation of persimmon. For this purpose, suppression subtractive hybridization (SSH) analysis was performed between astringency-removed fruits with ethanol treatment on the tree and non-treated fruits. According to this analysis, we were able to obtain several candidates for the genes involved in tannin accumulation into the fruits.3)As for investigation of a dominant gene conferring the trait of Chinese-type PCNA, we looked for molecular markers by AFLP method combined with bulked segregant analysis (BSA) using progenies derived from a Chinese PCNA 'Luo Tian Tian Shi'. By this analysis, we found three markers closely linked to the Chinese-PCNA trait. Using a marker among them, we screened genomic library of `Luo Tian Tian Shi' and obtained a genomic clone as the seed for constructing contig for the survey of the gene.