Quantitative proteomics of heavy metal exposure in Arabidopsis thaliana reveals alterations in one-carbon metabolism enzymes upon exposure to zinc
Quantitative proteomics of heavy metal exposure in Arabidopsis thaliana reveals alterations in one-carbon metabolism enzymes upon exposure to zinc
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DOI：
10.1016/j.jprot.2014.03.006
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发表时间：
2014-12-05
影响因子：
3.3
通讯作者：
Pantoja, Omar
中科院分区：
文献类型：
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作者：
Barkla, Bronwyn J.;Vera-Estrella, Rosario;Pantoja, Omar
植物锌（Zn）的体内平衡必须严格调节，因为对这种微量营养素的需求需要其吸收。然而，过量的锌会导致毒性，植物必须在其能力范围内迅速有效地作出反应，以尽量减少损害。为了检测机制，可能是重要的应对过剩的锌，我们进行了定量蛋白质组学的方法，使用2D-DIGE，以确定锌响应蛋白的微粒体组分4天，200亩锌处理，拟南芥植物的叶子。在Zn处理的样品中显示丰度显著变化并且在统计分析后满足所有选择标准的8种蛋白质中，6种通过LC MS/MS用2种或更多种独特肽成功鉴定。三种蛋白质被发现参与一碳代谢途径，包括甘氨酸脱羧酶P蛋白，丝氨酸羟甲基转移酶（SHMT）和甲硫氨酸合酶，所有这些都显示出减少的丰度在锌处理的样品。蛋白质印迹分析证实了SHMT的减少，而金属耐受蛋白的变化表明植物最有可能积极螯合锌。有趣的是，过量的Zn导致叶柄长度增加，这可能反映了蛋氨酸水平降低的表型，蛋氨酸是一碳代谢途径的关键产物。高水平的锌可以在某些土壤中自然发现，或者由于长期的人为活动导致其积累;即使用肥料或工业废物。金属耐受植物，特别是那些被归类为hyperoxia的植物的研究已经被这些植物用于生物修复目的的潜在用途所驱动。然而，重金属暴露对敏感植物的影响以及受影响的不同细胞过程受到的关注明显较少。我们对鉴定A. thaliana，是由于暴露于亚毒性水平的重金属，目的是发现新的参与者在重金属压力和适应诱导。(C)2014爱思唯尔有限公司版权所有。
Plant zinc (Zn) homeostasis must be tightly regulated as the requirement for this micronutrient necessitates its uptake. However, excessive Zn can lead to toxicity and the plant must respond rapidly and effectively within its capacity to minimize damage. To detect mechanisms that may be important for coping with excess Zn we carried out a quantitative proteomics approach using 2D-DIGE to identify Zn-responsive proteins in microsomal fractions from leaves of 4 day, 200 mu M Zn-treated, Arabidopsis thaliana plants. Of the eight proteins which showed significant changes in abundance in the Zn-treated samples and which met all of the selection criteria following statistical analysis, six were successfully identified by LC MS/MS with 2 or more unique peptides. Three of the proteins were found to be involved in the one-carbon metabolism pathway; including glycine decarboxylase P protein, serine hydroxymethyltransferase (SHMT) and methionine synthase, all of which showed reduced abundance in the Zn-treated samples. Western blot analysis confirmed the decrease in SHMT, while changes in metal tolerance protein indicated plants were most likely actively sequestering Zn. Interestingly, excess Zn led to increased petiole length, a phenotype which may reflect the reduced levels of methionine, a key product of the one-carbon metabolism pathway.Biological significanceMetal contamination is becoming an increasingly common environmental problem. High levels of zinc can be found in certain soils naturally or as a result of long-term anthropogenic activity which leads to its accumulation; i.e. use of fertilizers or industrial waste. The study of metal tolerant plants, particularly those classified as hyperaccumulators has been driven by the potential use of these plants for bioremediation purposes. However, the effects of heavy metal exposure on sensitive plants and the different cellular processes that are affected have received significantly less attention. We are interested in identifying proteins in A. thaliana that are induced as a result of exposure to subtoxic levels of heavy metals with the aim of discovering novel participants in heavy metal stress and adaptation. (C) 2014 Elsevier B.V. All rights reserved.