2005 Fiscal Year Final Research Report Summary
Genetic modification of amylopectin fine structure in endosperm starch of rice
| Project/Area Number |
14206003
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Breeding science
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| Research Institution | KYUSHU UNIVERSITY |
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Principal Investigator |
SATOH Hikaru KYUSHU UNIVERSITY, Fuculty of Agriculture, Professor, 大学院・農学研究院, 教授 (70128031)
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| Co-Investigator(Kenkyū-buntansha) |
KUMAMARU Toshihiro KYUSHU UNIVERSITY, Fuculty of Agriculture, Associate Professor, 大学院・農学研究院, 助教授 (00284555)
HANASIRO Isao Kagoshima University, Fuculty of Agriculture, Associate Professor, 農学部, 助教授 (30336325)
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| Project Period (FY) |
2002 – 2005
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| Keywords | Rice / Endosperm Starch / Mutation / Amylopectin / Genetic Resources / Starch Biosynthetic Enzymes / Breeding |
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| Research Abstract |
We obtained newly more than 1,200 mutants modifying amylopectin fine structure by MNU treatment. At least 10 independent enzymes were participated in amylopectin biosynthesis, those are, 5 kinds of SSS, 3 of BE and 2 of DBE. The mutations of genes encoding respective enzymes involved in amylopectin biosynthesis were isolated,
BE IIb mutation decreased specifically the short chains with less than DP 17 and increased longer chains with more than DP19. Contrarily, the amylopectin of BE I mutant was characterized by the significant decrease in long chains with more than DP 38 and the short chains with DP 12 to 23, and marked increase in short chains with less than DP12. The endosperm starch from the BE I mutant had the lower onset temperature for thermo-gelatinization. By contrast, BE IIb mutant showed the higher onset temperature for thermo-gelatinization. These findings indicate that the genetic modification of amylopectin fine structure is responsible for changes in physicochemical and rheological properties of the starch. The results support the view that alterations in amylopectin structure, in particular in short chains within clusters, might play a critical role in the rheological properties of starch. It is, therefore, likely that genetic modification of the gene for BEs will lead to the synthesis of novel types of starch as new materials for the foods and starch industries. ISA deficient mutations increased the short chains and decreased long chains dramatically. Rheological properties of DBE mutant are characterized by extremely lower viscosity in contrast to that of wild type. SS mutations altered the fine structure of amylopectin and their rheological properties as well as BE and DBE mutations. These results imply that amylopectin fine structure is important in determination of rheological properties of starch and genetic modification lead to the development of novel starch in rice.
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Research Products
(27 results)
