- 著者
- Yusuke Kamiyoshihara Takuya Nakamura Yasuharu Itagaki Shinichi Asada Takashi Aoki Shinji Mizuno Keiichi Watanabe Hiroaki Inoue Akira Tateishi
- 出版者
- The Japanese Society for Horticultural Science
- 雑誌
- The Horticulture Journal (ISSN:21890102)
- 巻号頁・発行日
- pp.OKD-133, (Released:2018-02-01)
- 被引用文献数
- 2
Actinidin is a major protein contained in kiwifruit (Actinidia spp.). While uptake of actinidin is beneficial to help gastric protein digestion with cysteine protease activity, the protein is also recognized as a major elicitor of allergy which can induce tingling in the oral cavity and occasionally severe anaphylactic reactions. Given that consumption of fresh kiwifruit has increased globally, development of Actinidia cultivars with lower level of actinidin is required to reduce the risk of allergenicity. In the present study, we examined variations in the actinidin level in Actinidia varieties. Among several varieties having trace amounts of actinidin, A. chinensis ‘Kohi’ was targeted to be analyzed for the molecular basis for the phenotype. ‘Kohi’ had below the detectable transcript level of Act1a, a critical gene for actinidin level. The upstream region of Act1a in ‘Kohi’ constituted different sequences from that of A. deliciosa ‘Hayward’, which has an active promoter for high expression of Act1a. The ‘Kohi’ sequence in the diverged region (upstream from −873 b) was rich in cytosine residues methylated at a higher level than in ‘Hayward’. Our data suggest the possibility of novel epigenetic regulation to reduce the actinidin level. The molecular mechanism for the phenotype in ‘Kohi’ was differentiated from ‘Hort16A’, a globally popular cultivar with a low level of actinidin. This cultivar could be a choice as a genetic resource in breeding to develop cultivars with controlled actinidin levels.
- 著者
- Yusuke Kamiyoshihara Shinji Mizuno Mirai Azuma Fumika Miyohashi Makoto Yoshida Junko Matsuno Sho Takahashi Shin Abe Hajime Shiba Keiichi Watanabe Hiroaki Inoue Akira Tateishi
- 出版者
- The Japanese Society for Horticultural Science
- 雑誌
- The Horticulture Journal (ISSN:21890102)
- 巻号頁・発行日
- pp.OKD-142, (Released:2018-01-26)
- 被引用文献数
- 1
Avocado fruit ripen with ethylene production after harvest and the flesh becomes soft and edible due to degradation of cell wall polysaccharides during ripening. α-l-Arabinofuranosidase is a hydrolytic enzyme known to digest arabinose-containing cell wall polysaccharides. It has been shown that its activity increased with fruit ripening. However, our previous study showed that an α-l-arabinofuranosidase gene (PaArf/Xyl3A) is expressed in the avocado fruit before ethylene production. In addition, the transcripts were detected in some organs in which the level of ethylene was extremely low. These results indicate that the gene expression is independent of ethylene. In the present study, we carried out immunoblot analyses of α-l-arabinofuranosidase at the protein level. Using a polyclonal antibody raised against Japanese pear α-l-arabinofuranosidase, two α-l-arabinofuranosidase proteins with molecular masses of 72 kDa and 68 kDa, presumably belonging to glycoside hydrolase family 3, were detected in ripening avocado fruit. The protein levels in ethylene or 1-methylcyclopropene (1-MCP)-treated fruits were examined and the results indicated that the two proteins responded to ethylene in opposite ways; the 68 kDa protein showed a temporary accumulation, whereas the 72 kDa protein exhibited dissipation possibly caused by a loss of stability. The total enzyme activity of α-l-arabinofuranosidase was elevated faster in the ethylene-treated fruit throughout ripening and was slower in the 1-MCP-treated fruit, suggesting the existence of another α-l-arabinofuranosidase, which did not cross-react with the antibody and was positively regulated by ethylene, in ripening avocado fruit.