| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1997: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1996: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1995: ¥700,000 (Direct Cost: ¥700,000)
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| Research Abstract |
We tried to analyze at a molecular level on the response of the cells to GA by using GA insensitivity mutants (Rht3) of wheat. GA sensitivity of the aleurone layrs of normal wheat seeds develops after 40 days post-flowering time, while in the Rht3 mutants, the GA sensitivity has not developed during seed development. In mature seeds of the Rht3 mutants aleurone tissues showed a low sensitivity to GA.Also, GA sensitivity of Rht3 aleurone was recovered when these seeds were treated with chilling treatment (5C for 48h). These results suggests that Rht3 mutant has not a deficient mutation and probably has a partial modification in a function of the Rht3 gene product. Also, the change in sensitivity by the chilling treatment suggests that this factor exists in the cell membrane. Two dimension electrophoretic analysis of aleurone protein (40 days after flowering) showed about 20 different polypeptide spots between normal and Rht3 lines. Among these polypeptides, we speculate one membrane bound polypeptide (named No.2, about 38KD) to be a candidate protein related to GA insensitivity since the other polypeptides shifted to a large extent in size. We tried to find a gene related to GA sensitivity by the differential display method, using aleurone (30 days after flowering) RNA of a normal and Rht3 wheats. However, we did not succeed to find any PCR fragments related to GA insensitivity. One of the reasons is that Rht3 mutation is not a deletion mutation. In future, using the semi-isogenic lines of the Rht3 mutation, it is necessary to examine whether No.2 polypeptide is really related to the GA sensitivity.
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