부산대학교 도서관

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jplph.2009.06.002 Byline: Takashi Akiyama (a), Shigeki Jin (b), Midori Yoshida (a), Tamotsu Hoshino (c), Rodjana Opassiri (d), James R. Ketudat Cairns (d) Keywords: Endo-(1,3,1,4)-[beta]-glucanase; Leaf elongation; Phytohormone; Rice seedling; Wounding treatment Abbreviations: ABA, abscisic acid; GA, gibberellin A3; MeJA, methyl jasmonate; Salicylate, sodium salicylate; 2,4-D, 2,4-dichlorophenoxyacetic acid Abstract: We isolated two rice endo-(1,3;1,4)-[beta]-glucanase genes, denoted OsEGL1 and OsEGL2, which encoded proteins that shared 64% amino acid sequence identity. Both the OsEGL1 and OsEGL2 genes were successfully expressed in Escherichia coli to produce functional proteins. Purified OsEGL1 and OsEGL2 proteins hydrolyzed (1,3;1,4)-[beta]-glucans, but not (1,3;1,6)-[beta]-linked or (1,3)-[beta]-linked glucopolysaccharides nor carboxymethyl cellulose, similar to previously characterized grass endo-(1,3;1,4)-[beta]-glucanases. RNA blot analysis revealed that the OsEGL1 gene is expressed constitutively not only in young roots of rice seedlings, but also in mature roots of adult rice plants. Little or no expression of the OsEGL2 gene was observed in all tissues or treatments tested, but database and RT-PCR analysis indicated it is expressed in ripening panicle. In rice seedling leaves, OsEGL1 gene expression significantly increased in response to methyl jasmonate, abscisic acid, ethephon and mechanical wounding. Mechanical wounding also increased the leaf elongation rate in rice seedlings by 16% relative to that of control seedlings at day 4 after treatment. The increase in the leaf elongation rate of rice seedlings treated under mechanical wounding was concomitant with an increase in OsEGL1 expression levels in seedling leaves. Author Affiliation: (a) National Agricultural Research Center for Hokkaido Region, 1 Hitsujigaoka, Toyohira-ku, Sapporo 062-8555, Japan (b) Graduate School of Health Sciences, Hokkaido University, N12W5, Kita-ku, Sapporo 060-0812, Japan (c) National Research Institute of Advanced Industrial Science and Technology, 2-17-2-1 Tsukisamu-higashi, Toyohira-ku, Sapporo 062-8517, Japan (d) Schools of Biochemistry and Chemistry, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand Article History: Received 8 April 2009; Revised 4 June 2009; Accepted 9 June 2009