著者

Hayashi Mari Kodama Momoko Nakamura Yasunori Fujita Naoko

出版者

日本応用糖質科学会

雑誌

Journal of Applied Glycoscience (ISSN:13447882)

巻号頁・発行日

vol.62, no.2, pp.81-86, 2015

被引用文献数

16

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Starch is glucose polymer linked by α-1,4 and α-1,6 glucosidic bonds. The balance of activity between starch synthases (SSs) and branching enzymes (BEs) is important for formation of amylopectin structure. SSI and SSIIIa isozymes account for 60 and 30%, respectively, of soluble SS activity in developing rice endosperm. Complete loss of both SSI and SSIIIa activities induces sterility. By contrast, a double mutant (<i>ss1^L/ss3a</i>) generated by crossing the leaky <i>ss1</i> mutant, whose SS activity is approximately ca. 16% of the wild type, and the <i>ss3a</i> null mutant is fertile. Although there is only a significant residual SS activity in the developing endosperm of <i>ss1^L/ss3a</i>, the yield and growth of the double-mutant line is sufficient. We analyzed the amylopectin chain-length distribution, thermal and pasting properties, morphologies of starch granules and amyloplasts, and crystallinity of endosperm starch in <i>ss1^L/ss3a</i> and the parental mutant lines. The chain-length distribution pattern of <i>ss1^L/ss3a</i> was similar to that of <i>ss3a</i> and there was an additive effect of the reduction of SSI activity on the chain-length of amylopectin in the <i>ss3a</i> background. These changes in the amylopectin chain-length distribution were considered to increase the gelatinization temperature of the starch. The gelatinized starch viscosity of the double-mutant and <i>ss3a</i> lines was very low. Most <i>ss1^L/ss3a</i> starch granules were round-shaped, and the starch granular size was smaller than those of the parental mutant lines and the wild type. The starch crystallinity of <i>ss1^L/ss3a</i> was slightly reduced compared with that of the wild type.

著者

Hayashi Mari Kodama Momoko Nakamura Yasunori Fujita Naoko

出版者

The Japanese Society of Applied Glycoscience

雑誌

Journal of Applied Glycoscience (ISSN:13447882)

巻号頁・発行日

2015

被引用文献数

16

---

Starch is glucose polymer linked by α-1,4 and α-1,6 glucosidic bonds. The balance of activity between starch synthases (SSs) and branching enzymes (BEs) is important for formation of amylopectin structure. SSI and SSIIIa isozymes account for 60% and 30%, respectively, of soluble SS activity in developing rice endosperm. Complete loss of both SSI and SSIIIa activities induces sterility. By contrast, a double mutant (<i>ss1^L/ss3a</i>) generated by crossing the leaky <i>ss1</i> mutant, whose SS activity is approximately ca. 16% of the wild type, and the <i>ss3a</i> null mutant is fertile. Although there is only a significant residual SS activity in the developing endosperm of <i>ss1^L/ss3a</i>, the yield and growth of the double-mutant line is sufficient. We analyzed the amylopectin chain-length distribution, thermal and pasting properties, morphologies of starch granules and amyloplasts, and crystallinity of endosperm starch in <i>ss1^L/ss3a</i> and the parental mutant lines. The chain-length distribution pattern of <i>ss1^L/ss3a</i> was similar to that of <i>ss3a</i> and there was an additive effect of the reduction of SSI activity on the chain-length of amylopectin in the <i>ss3a</i> background. These changes in the amylopectin chain-length distribution were considered to increase the gelatinization temperature of the starch. The gelatinized starch viscosity of the double-mutant and <i>ss3a</i> lines was very low. Most <i>ss1^L/ss3a</i> starch granules were round-shaped, and the starch granular size was smaller than those of the parental mutant lines and the wild type. The starch crystallinity of <i>ss1^L/ss3a</i> was slightly reduced compared with that of the wild type.