Involvement of calcium and calmodulin in protein and amino acid metabolism in rice [Oryza sativa] roots under anoxia
1995
Aurisano, N. (C.N.R. Istituto Biosintesi Vegetali, Milano (Italy)) | Bertani, A. | Reggiani, R.
The pretreatment of rice roots for 1 h in aerobic conditions with the Ca(2+)-channel blockers ruthenium red (RR) and verapamil and the calmodulin (CaM) antagonists N-(6-aminohexyl)-5-chloro-1-naphtylenesulfonamide (W-7) and trifluoperazine, induced during 3 h of anoxia: (1) inhibition of amino acid and gamma-aminobutyric acid (Gaba) accumulation; (2) a decline in the protein content; (3) a release of amino acids and K(+) into the growth media. The calcium ionophore A23187 reversed these effects in RR-treated roots. Moreover, the aerobic pretreatment of rice roots with A23178 alone or CaCl2 increased the accumulation of amino acids and Gaba. These data indicate that the Ca(2+)/CaM complex is involved in the transduction of an anaerobic signal by inhibiting proteolysis and solute release, and activating the Ca(2+)/CaM-dependent glutamate decarboxylase
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