InBioS-PhytoSystems, Functional Genomics and Plant Molecular Imaging, University of Liège, Liège, B-4000, Belgium.
Physiology and Plant Molecular Genetics, Free University of Brussels, Brussels, 1050, Belgium.
New Phytol. 2018 Apr;218(1):269-282. doi: 10.1111/nph.14949. Epub 2018 Jan 2.
Zinc (Zn) hyperaccumulation and hypertolerance are highly variable traits in Arabidopsis halleri. Metallicolous populations have evolved from nearby nonmetallicolous populations in multiple independent adaptation events. To determine whether these events resulted in similar or divergent adaptive strategies to high soil Zn concentrations, we compared two A. halleri metallicolous populations from distant genetic units in Europe (Poland (PL22) and Italy (I16)). The ionomic (Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES)) and transcriptomic (RNA sequencing (RNA-Seq)) responses to growth at 5 and 150 μM Zn were analyzed in root and shoot tissues to examine the contribution of the geographic origin and treatment to variation among populations. These analyses were enabled by the generation of a reference A. halleri transcriptome assembly. The genetic unit accounted for the largest variation in the gene expression profile, whereas the two populations had contrasting Zn accumulation phenotypes and shared little common response to the Zn treatment. The PL22 population displayed an iron deficiency response at high Zn in roots and shoots, which may account for higher Zn accumulation. By contrast, I16, originating from a highly Zn-contaminated soil, strongly responded to control conditions. Our data suggest that distinct mechanisms support adaptation to high Zn in soils among A. halleri metallicolous populations.
锌（Zn）超积累和超耐性是拟南芥耐锌性的高度可变性特征。金属矿区种群是从附近的非金属矿区通过多次独立的适应事件进化而来的。为了确定这些事件是否导致了对高土壤锌浓度的类似或不同的适应策略，我们比较了来自欧洲不同遗传单位的两个拟南芥耐金属矿区种群（波兰（PL22）和意大利（I16））。在 5 和 150 μM Zn 条件下，分析了根和地上组织的离子组（电感耦合等离子体原子发射光谱法（ICP-AES））和转录组（RNA 测序（RNA-Seq））响应，以研究地理起源和处理对种群间变异的贡献。这些分析得益于参考拟南芥转录组组装的生成。遗传单位解释了基因表达谱中最大的变异，而两个种群的锌积累表型存在差异，对锌处理的共同反应很少。PL22 种群在根和地上部的高锌条件下表现出缺铁反应，这可能是其更高的锌积累的原因。相比之下，起源于高度锌污染土壤的 I16 对对照条件有强烈的响应。我们的数据表明，不同的机制支持拟南芥耐金属矿区种群适应土壤中的高锌。
