Variation in HMA4 gene copy number and expression among Noccaea caerulescens populations presenting different levels of Cd tolerance and accumulation
Variation in HMA4 gene copy number and expression among Noccaea caerulescens populations presenting different levels of Cd tolerance and accumulation
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DOI：
10.1093/jxb/ers104
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发表时间：
2012-06-01
影响因子：
6.9
通讯作者：
Verbruggen, Nathalie
中科院分区：
文献类型：
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作者：
Craciun, Adrian R.;Meyer, Claire-Lise;Verbruggen, Nathalie
超富集植物蓝球藻（Necreea caerulescens）（以前称为Thlaspi caerulescens）在其耐受和积累镉的能力方面存在巨大的差异。为了获得新的见解，这种变化的机制，我们估计镉通量和进一步表征的N。caerulescens重金属ATP酶4（NcHMA 4）基因在三个种群（两个炉甘石，圣费利克斯德Pallieres，法国和Prayon，比利时;一个蛇纹石，Puente Basadre，西班牙）呈现出不同的耐受性和积累水平。镉的吸收和转运不同的人群以同样的方式积累，人口与最高的镉浓度在地上部（圣费利克斯-德-Pallieres）提出了最高的吸收和转运能力。我们证明了在以前的研究中确定的四个NcHMA 4拷贝在物种水平上是不固定的，并且在C-末端部分截短的拷贝编码功能蛋白。蛇形种群中NcHMA 4表达和基因拷贝数较低，与炉甘石种群相比，这是镉转运效率最低的种群。NcHMA 4表达与所有器官中的血管组织相关，在冠部最大。总的来说，我们的研究结果表明，镉转运能力的差异所研究的人口似乎控制，至少部分地，由NcHMA 4，而过度表达的NcHMA 4在两个炉甘石人口可能会导致趋同进化。
There is huge variability among populations of the hyperaccumulator Noccaea caerulescens (formerly Thlaspi caerulescens) in their capacity to tolerate and accumulate cadmium. To gain new insights into the mechanisms underlying this variability, we estimated cadmium fluxes and further characterized the N. caerulescens heavy metal ATPase 4 (NcHMA4) gene in three populations (two calamine, Saint-Felix-de-Pallieres, France and Prayon, Belgium; one serpentine, Puente Basadre, Spain) presenting contrasting levels of tolerance and accumulation. Cadmium uptake and translocation varied among populations in the same way as accumulation; the population with the highest cadmium concentration in shoots (Saint Felix-de-Pallieres) presented the highest capacity for uptake and translocation. We demonstrated that the four NcHMA4 copies identified in a previous study are not fixed at the species level, and that the copy truncated in the C-terminal part encodes a functional protein. NcHMA4 expression and gene copy number was lower in the serpentine population, which was the least efficient in cadmium translocation compared to the calamine populations. NcHMA4 expression was associated with the vascular tissue in all organs, with a maximum at the crown. Overall, our results indicate that differences in cadmium translocation ability of the studied populations appear to be controlled, at least partially, by NcHMA4, while the overexpression of NcHMA4 in the two calamine populations may result from convergent evolution.