The Arabidopsis YELLOW STRIPE LIKE4 and 6 Transporters Control Iron Release from the Chloroplast
The Arabidopsis YELLOW STRIPE LIKE4 and 6 Transporters Control Iron Release from the Chloroplast
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DOI：
10.1105/tpc.112.107672
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发表时间：
2013-03-01
期刊：
影响因子：
11.6
通讯作者：
Curie, Catherine
中科院分区：
文献类型：
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作者：
Divol, Fanchon;Couch, Daniel;Curie, Catherine
在大多数植物细胞类型中，叶绿体是铁的最大储存库，铁对叶绿体代谢至关重要，但也容易造成氧化损伤。在此，我们表明，为了缓冲铁的潜在有害影响，除了铁蛋白用于储存外，叶绿体还配备了特定的铁转运蛋白，这些蛋白通过将铁从叶绿体中移除来应对铁毒性。我们描述了拟南芥YELLOW STRIPE1 - LIKE家族的两种转运蛋白YSL4和YSL6，它们可能具有这一功能。敲除YSL4和YSL6会大大降低植物应对过量铁的能力。生化和免疫定位分析表明，YSL6位于叶绿体包膜上。元素分析和组织化学染色显示，铁被困在ysl4 ysl6双突变体的叶绿体中，该突变体还积累铁蛋白。此外，液泡铁的再动员以及NRAMP3/4的表达受到抑制。而且，YSL4或YSL6的普遍表达会显著降低植物对缺铁的耐受性，并降低叶绿体铁含量。这些数据证明了YSL4和YSL6在管理叶绿体铁方面的重要作用。YSL4和YSL6的表达模式支持它们在胚胎发生和衰老过程中质体去分化期间对铁解毒的生理作用。
In most plant cell types, the chloroplast represents the largest sink for iron, which is both essential for chloroplast metabolism and prone to cause oxidative damage. Here, we show that to buffer the potentially harmful effects of iron, besides ferritins for storage, the chloroplast is equipped with specific iron transporters that respond to iron toxicity by removing iron from the chloroplast. We describe two transporters of the YELLOW STRIPE1-LIKE family from Arabidopsis thaliana, YSL4 and YSL6, which are likely to fulfill this function. Knocking out both YSL4 and YSL6 greatly reduces the plant's ability to cope with excess iron. Biochemical and immunolocalization analyses showed that YSL6 resides in the chloroplast envelope. Elemental analysis and histochemical staining indicate that iron is trapped in the chloroplasts of the ysl4 ysl6 double mutants, which also accumulate ferritins. Also, vacuolar iron remobilization and NRAMP3/4 expression are inhibited. Furthermore, ubiquitous expression of YSL4 or YSL6 dramatically reduces plant tolerance to iron deficiency and decreases chloroplastic iron content. These data demonstrate a fundamental role for YSL4 and YSL6 in managing chloroplastic iron. YSL4 and YSL6 expression patterns support their physiological role in detoxifying iron during plastid dedifferentiation occurring in embryogenesis and senescence.