Unique segregation of the trait of astringency-loss in a Chinese PCNA cultivar and its molecular biology for tannin accumulation

到目前为止，人们认为中国身上不存在无涩类型的柿。然而，最近在中国楼田柿中发现了一种授粉常数不收敛柿，该品种‘罗天甜柿’表现出非常独特的收敛性状。‘罗天天实’与日本增殖细胞核抗原杂交时，有几个后代结果收敛，为了证实这一现象，测定了区分增殖细胞核抗原与非增殖细胞核抗原的良好指标--单宁细胞大小。因此，我们证实了‘罗天天狮’与日本增殖细胞核抗原品种杂交所产生的非增殖细胞核抗原在后代中的得率较高，并阐明了‘罗天天狮’与日本增殖细胞核抗原品种果实中单宁的化学性质有很大的不同。‘罗天天狮’单宁的相对分子质量和与乙醛的凝聚反应速度均快于日本品种。‘罗天天时’单宁的化学性质与非增殖细胞核抗原品种相似，而参与单宁生物合成的第一步--类黄酮合成的基因表达也与日本的‘罗天天时’不同，说明‘罗天天时’表现出独特的收敛特性，这可能是由于参与类黄酮生物合成的基因表达不同所致。

So far, it was thought that no non-astringent-type persimmons exist in China. However, a pollination constant non-astringent (PCNA) persimmon was recently found in Lou Tian Tian province of China, and this PCNA-type cultivar, 'Luo Tian Tian Shi', have showed very unique trait for astringency. When 'Luo Tian Tian Shi' was crossed wish a Japanese PCNA cultivar, several offspring bore astringent fruits.In order to confirm this phenomenon, tannin cell size that is a good index to distinguish PCNA from non-PCNA was determined. As the result, we were able to confirm that non-PCNA offsping by a cross between 'Luo Tian Tian Shi' and a Japanese PCNA cultivar were yielded wish a relatively high rate in the offspring.We also clarified that the chemical properties of tannins in the fruit is quite different between 'Luo Tian Tian Shi' and Japanese PCNA cultivars. Tannins from 'Luo Tian Tian Shi' showed higher molecular weight and faster coagulation reaction with acetaldehyde than in Japanese PCNA cultivars. The chemical properties of tannins of 'Luo Tian Tian Shi' were resemble to those of non-PCNA cultivars.Furthermore, gene expressions involved in flavonoid biosynthesis, which is the first step for tannin biosynthesis, were also different between 'Luo Tian Tian Shi' and Japanese PCNA cultivars.As a conclusion, we could demonstrated a unique trait of astringency in 'Luo Tian Tian Shi', which was thought to be due to a difference of gene expressions involved in flavonoid biosynthesis.