CLASSIFICATION OF JAPANESE PEAR CULTIVARS BY ISOZYME AND DNA ANALYSIS AND CONSTRUCTION OF PHYLOGENETIC TREES

目前尚不清楚日本梨品种(梨)是从中国或韩国进口的，还是在日本的梨的基础上改良的。这些调查是为了在分子水平上阐明这一点。通过叶绿体DNA区域的PCR-RFLP分析，揭示了梨属植物(主要是日本梨)的母系亲缘关系。利用差异显示技术分离到一个克隆JPROMT，其预测的氨基酸残基与植物O-甲基转移酶高度相似。Northern分析表明，JPROMT在中国梨的成熟果实中没有表达，而在日本梨和欧洲梨的成熟果实中表达。JPROMT是区分于日本梨、中国梨和欧洲梨的有用分子。两个1-氨基环丙烷-1-羧酸(ACC)合成酶基因(PPACS1和PPACS2)也被证明是区分日本梨品种的有用标记。

It is unclear whether Japanese pear cultivars (Pyrus pyrifolia Nakai) were imported from China or Korea or improved on Pyrus serotina in Japan. The investigations were conducted to make it clear at molecular level. The maternal relationship in Pyrus species (mainly Japanese pear) was revealed by PCR-RFLP analysis of chloroplast DNA regions. A cDNA clone, JPROMT, was isolated by differential display and its predicted amino acid residues showed high similarity to plant O-methyltransferase. Northern analysis showed that the expression of JPROMT was not observed in ripening fruits of Chinese pear, but in ripening fruits of Japanese pear and European pear. JPROMT was shown to be an useful molecular distinguishing from Japanese, Chinese and European pear. Two 1-aminocyclopropane-1-carboxylate (ACC) synthase genes (PPACS1 and PPACS2) were also shown to be useful markers to classify Japanese pear cultivars.