Possible Involvement of Phosphoinositide-Ca2+ Signaling in the Regulation of -Amylase Expression and Germination of Rice Seed (Oryza sativa L.)
Open Access
- 1 April 2000
- journal article
- research article
- Published by Oxford University Press (OUP) in Plant and Cell Physiology
- Vol. 41 (4) , 399-407
- https://doi.org/10.1093/pcp/41.4.399
Abstract
We have studied the effects of neomycin, a potent inhibitor of inositol phospholipid-specific phospholipase C (PLC), on the germination of rice seed and the gibberellin-induced expression of a-amylase in the aleurone layer and the scutellar tissues. It was shown that, in the absence of exogenous Ca2+, neomycin markedly reduced the germination speed and seedling growth of rice seeds and inhibited the gibberellin-induced expression of a-amylase in both secretory tissues. In addition, neomycin decreased the formation of inositol 1,4,5-trisphosphate (IP3) in the gibberellin-treated aleurone layer and the scutellar tissues. However, the inhibitory effects on the germination speed and the expression of a-amylase activity were overcome by supplementation of Ca2+. In addition, gibberellin elevated the level of IP3, and ABA prevented the gibberellin-induced formation of IP3, although ABA alone did not alter the IP3 level. The expression of a membrane-bound PLC molecule in rice aleurone layer was shown to be induced by gibberellin, and the gibberellin-induced expression of PLC was markedly delayed by treatment with ABA. These results strongly suggest that the phosphoinositide-Ca2+ signal transduction pathway may play an important role in the gibberellin-induced expression of a-amylase molecules closely related to the germination processes of rice seed.Keywords
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