2000 Fiscal Year Final Research Report Summary
Improvement of grain quality and taste based on amino acid composition in rice endosperm.
| Project/Area Number |
11460002
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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 |
Breeding science
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| Research Institution | Yamagata University |
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Principal Investigator |
SASAHARA Takeo Agriculture, Yamagata University Professor, 農学部, 教授 (20005606)
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| Co-Investigator(Kenkyū-buntansha) |
ABE Toshinori Agriculture, Yamagata University Associate Professor, 農学部, 助教授 (80202670)
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| Project Period (FY) |
1999 – 2000
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| Keywords | Oryza sativa / endosperm / free amino acids / GABA / UGPase / cDNA |
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| Research Abstract |
1) Varietal difference of free amino acids and GABA contents in rice endosperm.
Fourtytwo rice varieties including subspecies of Japonica (18), Indica (19) and Jawanica (5) were used to characterize free amino acid composition. In Japonica varieties, Asahi had very high total amino acid composition especially Asp and Glu. That amount was about 3 times of medium composition. Carlose was next to the Asahiin Glu concentration.. High taste Japonica varieties, Koshihikari and Sasanishiki had a similar pattern, The values of component was intermediate. In Indica varieties, Hadsadri and BlueBelle had high concentration of Glu and Asn, showing twise compared to normal indica varieties. GABA concentration was high in Hukunishiki in Japonica and Blue Belle and Coukoutou in Indica. From the analysis of variance, the difference of free amino acid composition among varieties was highly significant. That shows possibility of genetically elevating suitable amino acids.
2) Cloning of cDNA for UDP-glucose pyrophosphorylase and the expression of mRNA in rice endosperm.
Rice endosperm UDP-glucose pyrophosphorylase (UGPase) cDNA clones were isolated by screening λ ZAP library prepared from Poly (A+) RNA of Japonica rice endosperm. One clone possessing about 1700 nucleotides was the complete cDNA of rice UGPase. The amino acid sequence of enzyme deduced from the nucleotide sequence consist of 469 amino acid residues. The amino acid sequences of UGPase derived from cDNA sequence were highly homologous among rice, barely and potato, being 92% between rice and barley, and 85% between rice and potato. Copy number of the gene was estimated to be single which was examined by genomic Southern blotting. Expression of the enzyme in rice endosperm examined by Northern blot was high at 15 days after heading.
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