Metallothionein deficiency impacts copper accumulation and redistribution in leaves and seeds of Arabidopsis
Metallothionein deficiency impacts copper accumulation and redistribution in leaves and seeds of Arabidopsis
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DOI：
10.1111/nph.12718
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发表时间：
2014-05-01
期刊：
影响因子：
9.4
通讯作者：
Goldsbrough, Peter
中科院分区：
文献类型：
--
作者：
Benatti, Matheus R.;Yookongkaew, Nimnara;Goldsbrough, Peter
大多数被子植物基因组含有几个编码金属硫蛋白（MT）蛋白的基因，MT蛋白可以结合包括铜（Cu）和锌（Zn）在内的金属。金属硫蛋白基因在各种条件下高度表达，但关于其功能的信息有限。我们已经研究了拟南芥突变体，是在多个MT的缺陷，了解MT在植物中的功能。T-DNA插入被确定在四个拟南芥MT基因在营养组织中表达。这些杂交产生四种MT（mt 1a/mt 2a/mt 2b/mt3）缺陷的植物。铜的浓度是较低的种子，但较高的quad-MT突变体的老叶相比，野生型植物。稳定同位素实验表明，种子中的铜来自两个来源：直接来自根部和通过其他器官的再活化。铜的动员出衰老的叶片被破坏在MT缺陷的植物。铜，锌和百草枯的耐受性不受MT缺乏的影响，但这些植物对镉（Cd）的敏感性稍高。四MT突变体没有表现出任何变化，在一些微生物病原体的抗性，或在叶片衰老的进展。虽然这些MT不需要完成植物的生活史，MT是重要的铜稳态和分布在拟南芥。
Most angiosperm genomes contain several genes encoding metallothionein (MT) proteins that can bind metals including copper (Cu) and zinc (Zn). Metallothionein genes are highly expressed under various conditions but there is limited information about their function. We have studied Arabidopsis mutants that are deficient in multiple MTs to learn about the functions of MTs in plants. T-DNA insertions were identified in four of the five Arabidopsis MT genes expressed in vegetative tissues. These were crossed to produce plants deficient in four MTs (mt1a/mt2a/mt2b/mt3). The concentration of Cu was lower in seeds but higher in old leaves of the quad-MT mutant compared to wild-type plants. Experiments with stable isotopes showed that Cu in seeds came from two sources: directly from roots and via remobilization from other organs. Mobilization of Cu out of senescing leaves was disrupted in MT-deficient plants. Tolerance to Cu, Zn and paraquat was unaffected by MT deficiency but these plants were slightly more sensitive to cadmium (Cd). The quad-MT mutant showed no change in resistance to a number of microbial pathogens, or in the progression of leaf senescence. Although these MTs are not required to complete the plant's life cycle, MTs are important for Cu homeostasis and distribution in Arabidopsis.