Division of Applied Life Science (BK21 program), IALS, PMBBRC, Gyeongsang National University, Jinju 660-701, Republic of Korea.
Plant Sci. 2012 May;187:113-26. doi: 10.1016/j.plantsci.2012.02.002. Epub 2012 Feb 9.
Despite the widespread occurrence of chromium toxicity, its molecular mechanism is poorly documented in plants compared to other heavy metals. To investigate the molecular mechanisms that regulate the response of Miscanthus sinensis roots to elevated level of chromium, seedlings were grown for 4 weeks and exposed to potassium dichromate for 3 days. Physiological, biochemical and proteomic changes in roots were investigated. Lipid peroxidation and H₂O₂ content in roots were significantly increased. Protein profiles analyzed by two-dimensional gel electrophoresis revealed that 36 protein spots were differentially expressed in chromium-treated root samples. Of these, 13 protein spots were up-regulated, 21 protein spots were down-regulated and 2 spots were newly induced. These differentially displayed proteins were identified by MALDI-TOF and MALDI-TOF/TOF mass spectrometry. The identified proteins included known heavy metal-inducible proteins such as carbohydrate and nitrogen metabolism, molecular chaperone proteins and novel proteins such as inositol monophosphatase, nitrate reductase, adenine phosphoribosyl transferase, formate dehydrogenase and a putative dihydrolipoamide dehydrogenase that were not known previously as chromium-responsive. Taken together, these results suggest that Cr toxicity is linked to heavy metal tolerance and senescence pathways, and associated with altered vacuole sequestration, nitrogen metabolism and lipid peroxidation in Miscanthus roots.
尽管铬毒性广泛存在，但与其他重金属相比，其在植物中的分子机制仍未得到充分记录。为了研究调控芒根茎对高浓度铬响应的分子机制，将幼苗生长 4 周并暴露于重铬酸钾 3 天。研究了根中的生理、生化和蛋白质组变化。根中的脂质过氧化和 H₂O₂含量显著增加。通过二维凝胶电泳分析的蛋白质图谱显示，铬处理的根样品中有 36 个蛋白质斑点表达差异。其中，13 个蛋白质斑点上调，21 个蛋白质斑点下调，2 个斑点新诱导。通过 MALDI-TOF 和 MALDI-TOF/TOF 质谱鉴定了这些差异表达的蛋白质。鉴定的蛋白质包括已知的重金属诱导蛋白，如碳水化合物和氮代谢、分子伴侣蛋白，以及新型蛋白，如肌醇单磷酸酶、硝酸还原酶、腺嘌呤磷酸核糖转移酶、甲酸脱氢酶和一种假定的二氢硫辛酰胺脱氢酶，这些蛋白以前不被认为是对铬有反应的。总之，这些结果表明，Cr 毒性与重金属耐受和衰老途径有关，并与芒根茎中液泡隔离、氮代谢和脂质过氧化的改变有关。
