Proteome analysis of rice root proteins regulated by gibberellin

Abstract

To gain an enhanced understanding of the mechanism by which gibberellins (GAs) regulate the growth and development of plants, it is necessary to identify proteins regulated by GA. Proteome analysis techniques have been applied as a direct, effective, and reliable tool in differential protein expressions. In previous studies, sixteen proteins showed differences in accumulation levels as a result of treatment with GA(3), uniconazole, or abscisic acid (ABA), and/or the differences between the GA-deficient semi-dwarf mutant, Tan-ginbozu, and normal cultivars. Among these proteins, aldolase increased in roots treated with GA(3), was present at low levels in Tan-ginbozu roots, and decreased in roots treated with uniconazole or ABA. In a root elongation assay, the growth of aldolase-antisense transgenic rice was half of that of vector control transgenic rice. These results indicate that increases in aldolase activity stimulate the glycolytic pathway and may play an important role in the GA-induced growth of roots. In this review, we discuss the relationship among GA, aldolase, and root growth.

Fig. 1

Venn diagrams of the effects of the Tan-ginbozu semi-dwarfism, uniconazole-P, and ABA on protein accumulation. PR-1: type-1 pathogenesis-related protein; DAR: dehydroascorbate reductase; SOD: superoxide dismutase; PR-5: antifungal protein-R; NS: nicotianamine synthase; SalT: SalT protein; CYP: cyclophilin; BBTI: Bowman-Birk tripsin inhibitor.

Fig. 2

Schematic summary of the signal transduction between GA and root elongation. GA₃-induced aldolase enhances the metabolic rate of glycolysis in rice roots, and aldolase activates V-ATPase through physical interactions. As a result, the rate of cell growth in seedling roots may be significantly enhanced. Also, GA₃ signaling for root growth promotion may be mediated by CDPK13.