| Budget Amount *help |
¥11,900,000 (Direct Cost: ¥11,900,000)
Fiscal Year 1998: ¥2,500,000 (Direct Cost: ¥2,500,000)
Fiscal Year 1997: ¥9,400,000 (Direct Cost: ¥9,400,000)
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| Research Abstract |
Total andosperm proteins of japonica and indica cultivars, and their F_2 progeny were analyzed by two-dinmensional polyacrylamide gel electro-phoresis (2D-PAGE). Nine different high molecular weight (HMW) proteins were detected in the F_2 progeny fits with a ratio of 1 : 1 : 1 : 1 due to double fertilization. The dominantgenes appeared to regulate expression of the high molecular weight protein sub- units, and dose effect of dominant genes was detected.
The proteins which were extracted from endosperm of the rice seed were separated by 2D-PAGE, and were electroblotted onto a PVDF membrane. The partial amino acid sequences of the proteins were determined by automatic Edman degradation. The N-terninal sequences and the internal amino acid sequences were deter-mined. Structural homology searches resulted in identification of seven HMW proteins (enzymes), namely, starch debranching enzyme precursor (96 kD), pyruvate orthophosphate dikinase (94kD), malate dehydrogenase (45 kD), phosphoglycerate mutase (69 kD), enolase (57 kD), D-xylulose reductase (54 kD), and UDP-glucose pyrophosphorylase (51kD). In addition, three of the proteins appeared to be related to proteins in the heat shock family, i.e., chloroplast atroma heat shock related protein (HSP) (74 kD), Heat shock 70 kD protein (71 kD), and chloroplastchaperonin (67 kD). The three proteins (60, 43 and 42 kD) were found to have no homology with those of known plant and animal proteins. .These results may suggest that sucrose transferred from leaves to endosperm are consumed for sturch synthesis and glycolysis. Expression of the gene for pyruvate orthophosphate dikinase that is the key enzyme for C_4-dicarboxylic acid cycle was strong in the early stage of grain filling, The result might show it is concerned with carbon and amino acidmetabolysms.
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