ABSTRACT

Here we compare mineral accumulation and global gene expression patterns between two metal hyperaccumulator plants – Noccaea japonica, originating from Ni-rich serpentine soils, and Noccaea caerulescens (ecotype Ganges), originating from Zn/Pb-mine soils – under excess Ni conditions. Significant differences in the accumulation of K, P, Mg, B, and Mo were explained by the expression levels of specific transporters for each mineral. We previously showed that total Ni accumulation in the whole plant is higher in N. caerulescens than in N. japonica. Here we found a similar tendency for Fe under excess Ni; however, the expression of iron-regulated transporter 1 (IRT1), which encodes the primary Fe uptake transporter and causes excess Ni uptake in Arabidopsis thaliana, was higher in N. japonica. NjIRT1 has a point mutation at Asp100, which is essential for Fe transport, and so might lack its Fe and possibly Ni transport function. Noccaea japonica might have lost its IRT1 function, which would prevent excess Ni uptake via IRT1 in Ni-rich soils, and come to rely on other transporters.

摘要

在这里，我们比较了两种金属超富集植物——来自富镍蛇纹石土壤的Noccaea japonica和来自锌/铅矿土壤的Noccaea caerulescens （生态型恒河）在过量 Ni 条件下的矿物质积累和全球基因表达模式。K、P、Mg、B 和 Mo 积累的显着差异可以通过每种矿物的特定转运蛋白的表达水平来解释。我们之前的研究表明，蓝藻在全株中的总 Ni 积累量高于粳稻。在这里，我们发现在过量 Ni 下 Fe 也有类似的趋势；然而，铁调节转运蛋白 1 ( IRT1)，它编码主要的 Fe 摄取转运蛋白并导致拟南芥中过量的 Ni 摄取，在N. japonica中较高。NjIRT1 在 Asp100 处有一个点突变，这对于 Fe 转运至关重要，因此可能缺乏其 Fe 和可能的 Ni 转运功能。Noccaea japonica可能已经失去了其 IRT1 功能，这将阻止富 Ni 土壤中通过 IRT1 吸收过量的 Ni，并开始依赖其他转运蛋白。