1996 Fiscal Year Final Research Report Summary
Molecular Biological Analysis of Ripening Characteristics in Chinese Pear
| Project/Area Number |
07456019
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
園芸・造園学
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| Research Institution | Okayama University |
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Principal Investigator |
NAKAMURA Reiosuke Fac.Agri., Okayama Univ.Prof., 農学部, 教授 (70021053)
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| Co-Investigator(Kenkyū-buntansha) |
KUBO Yasutaka Fac.Agri., Okayama Univ.Asso.Prof., 農学部, 助教授 (80167387)
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| Project Period (FY) |
1995 – 1996
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| Keywords | Ripening ethylene / ACC synthase gene / ACC oxidase gene / Chinese pear / Climacteric fruit / Non-climacteric fruit |
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| Research Abstract |
Table pear fruit consist of Chinese pear, European pear and Japanese pear. Based on ripening ethylene biosynthesis, Chinese and European pear fruit are classified to Climacteric fruit, while Japanese pear fruit belongs to Non-climacteric fruit. We have found that several cultivars in Chinese pear must be grouped to Non-climacteric fruit, as they produce no ethylene at ripening stage.Present our research was supposed to investigate ripening characteristics in Chinese using recently developed molecular biological approach, which leads to substantial difference between climacteric and non-climacteric fruit.
1.The cDNAs that encode the rate limiting enzymes, ACC synthase and ACC oxidase, in ethylene biosynthesis in plant were cloned from 3 cultivars in Chinese pear and each one cultivar in European and Japanese pear by RT-PCR method. In total, 13 ACC synthase genes and 9 ACC oxidase genes were obtained. ACC synthase genes and ACC oxidase genes were grouped to 4 categories and 2 categories respectively by the phylogenetic analysis in deduced amino acid sequence.
2.The expression of two ACC synthase genes was detected in only climacteric cultivars at ripening stage by Northern blot analysis, while ACC oxidase gene expression accelerated with fruit ripening in any cultivars except 'Hong Lee'.
3.The mRNA accumulation of two ACC oxidase and two ACC synthase genes that was not detected with fruit ripening were commonly observed in response to wounding in fruit tissue in any cultivars.
4.Our results suggest that 2 ACC synthase genes specifically expressed on ripening fruit determine ripening ethylene in pear fruit, in other words the difference between climacteric fruit and non-climacteric fruit.
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