Hormonal regulation of the expression of cysteine proteinase genes in germinated cotyledons of common bean seeds
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Storage proteins in cotyledons of legume plants are degraded by proteinases after germination. We examined whether abscisic acid (ABA), gibberellin (GA) and brassinosteroid (BR) are involved in the expression of cysteine proteinases in cotyledons of common bean seeds with RNA blotting using cDNAs for five papain-like proteinases, EP-C1, CP1, CP2, CP3, CP4 and two legumain-like proteinases, LLP1 and LLP2 as probes. Six genes, except for CP4, are activated after seed imbibition. These germination-induced cysteine proteinase genes (<i>GICPs</i>) are repressed by exogenously applied (+)-5′α, 8′-cyclo-ABA which is more resistant to hydroxylation than ABA. Either GA<sub>3</sub> or epi-BR activated <i>GICPs</i> in the presence of ABA, suggesting that both of GA and BR are involved in the expression of <i>GICPs</i>. It is possible that GA biosynthesis is required for the activation of <i>GICPs</i>, because either GA-biosynthesis inhibitors, chloroethyltrimethyl-ammonium chloride or prohexadione calcium repressed <i>GICPs</i> and this repression was restored by exogenously applied GA<sub>3</sub>.
- Plant tissue culture letters
Plant tissue culture letters 24(2), 231-235, 2007-03-01
Japanese Society for Plant Cell and Molecular Biology