RESUMO
Cadmium (Cd) is one of the most toxic heavy metal elements in nature, and it causes serious damage to plant cells. Here, we report that a transcription factor OsMYB45 is involved in Cd stress response in rice. OsMYB45 is highly expressed in rice leaves, husks, stamens, pistils, and lateral roots, and its expression is induced by Cd stress. OsMYB45 fused to green fluorescent protein localized to the cell nucleus in onion epidermal cells. Mutation of OsMYB45 resulted in hypersensitivity to Cd treatment, and the concentration of H2O2 in the leaves of mutant nearly doubled, while catalase (CAT) activity was halved compared with the wild-type. Moreover, gene expression analysis indicated that OsCATA and OsCATC expression is significantly lower in the mutant than in the wild-type. In addition, overexpression of OsMYB45 in the mutant complemented the mutant phenotype. Taken together, OsMYB45 plays an important role in tolerance to Cd stress in rice.
Assuntos
Cádmio/toxicidade , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Oryza/genética , Fatores de Transcrição/metabolismo , Catalase/metabolismo , Flores/efeitos dos fármacos , Flores/genética , Flores/fisiologia , Expressão Gênica , Genes Reporter , Peróxido de Hidrogênio/metabolismo , Mutação , Cebolas/efeitos dos fármacos , Cebolas/genética , Cebolas/fisiologia , Especificidade de Órgãos , Oryza/efeitos dos fármacos , Oryza/fisiologia , Fenótipo , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/genética , Folhas de Planta/fisiologia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/genética , Raízes de Plantas/fisiologia , Proteínas Recombinantes de Fusão , Estresse Fisiológico , Fatores de Transcrição/genéticaRESUMO
It is not clear whether pseudoallergic reactions are caused by similar mechanisms as type I allergic reactions. 3Caffeoylquinic acid (chlorogenic acid) is an active ingredient in traditional Chinese medicines used for antibacterial, anti-inflammatory and cholagogic purposes. It is assumed to be the reason for the high allergic reaction rates associated with certain traditional Chinese medicine injection solutions. The aim of the present study was to investigate the possible mechanisms through which chlorogenic acid triggers pseudoallergic reactions. The fluidity of the cell membrane was investigated using fluorescence recovery after photobleaching. Western blot analysis was used to measure the phosphorylation levels of the Spleen tyrosine kinase (Syk) protein and Fluo3/AM fluorescent probes were used to investigate the influx of calcium ions. In addition, fluorescence microscopy and phalloidin were used to determine Factin depolymerization levels. The secretion rate of ßhexosaminidase by RBL2H3 cells clearly increased following treatment with chlorogenic acid and the levels of cytoskeletal disintegration were also markedly increased. Furthermore, we detected an increase in the intracellular calcium ion concentration along with distinct changes in Syk protein phosphorylation and cellular Factin. These changes indicated that chlorogenic acid affected the restructuring of the cytoskeleton and played a role in cell degranulation. In conclusion, chlorogenic acid may lead to the aggregation of lipid rafts on the cell membrane surface by altering RBL2H3 cell membrane fluidity, thus triggering Sykrelated signal transduction and inducing a truncated type I like allergic reaction.