Proteomic analysis of aluminium stressed Brachiaria using two-dimensional gel electrophoresis and LC/MS/MS system

摘要

Ruzigrass (Brachiaria ruziziensis) and signalgrass (Brachiaria decumbens) can grow better in low pH soil and the damage of their root elongation or biomass by aluminium (Al) is not serious compared to the other plants. However, those strategies for Al tolerant have not been clarified. The plant growth, Al absorption, calcium (Ca) and magnesium (Mg) concentrations in ruzigrass (Ru) and signalgrass (Sg) under 0.5 mM Al hydroponics culture were characterized in comparison with Job's tears (Jt), oat (Oa) and soybean (Sb). For Oa and Sb, the root elongation was terminated by Al application. The delaying in shoot and root growth of all the plant species was observed under Al treatment. Absorption of Ca and Mg was inhibited severely by Al treatment in Oa and Sb, compared with Ru, Sg and Jt. The Al content in the root tip parts was lower in Ru, Sg and Jt. However, no difference was observed between the root tip parts and whole root in Oa and Sb in terms of Al content. These results suggest that the tolerance to Al toxicity of Ru and Sg is due to the absorption of more Ca and Mg and less Al in root tip cells under Al stress environment. Soluble peptides were extracted from Al stressed Ru root tip by Tris-HCl (pH 8.5) buffer solution. The results of two-dimensional gel electrophoresis suggest that Al stress, at least, induced the increasing of 7 peptides and decreasing of 4 peptides. Amino acid sequences of increased peptides by Al stress were analyzed by LC/MS/MS System (Applied Biosystems). We have identified some peptides and established the specific relationship of those peptides with Al stress.