Influence of sulfate supply on selenium uptake dynamics and expression of sulfate/selenate transporters in selenium hyperaccumulator and nonhyperaccumulator Brassicaceae
Influence of sulfate supply on selenium uptake dynamics and expression of sulfate/selenate transporters in selenium hyperaccumulator and nonhyperaccumulator Brassicaceae
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硫酸盐供应对硒高积累和非高积累十字花科植物硒吸收动态和硫酸盐/硒酸盐转运体表达的影响
DOI：
10.1111/nph.14838
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发表时间：
2018-01-01
期刊：
影响因子：
9.4
通讯作者：
Schiavon, Michela
中科院分区：
文献类型：
--
作者：
El Mehdawi, Ali F.;Jiang, Ying;Schiavon, Michela
为了研究这种富硒的机制，我们用不同浓度的亚硒酸盐和竞争对手硫酸盐，在长期(9d)和短期(1h)的测定中，比较了羽状单胞菌和非超积累植物海甘蓝和芥菜对硒的吸收。不同的硫酸盐预处理(0、0.5、5 mM、3d)对硒吸收和硫酸盐转运蛋白表达的影响也进行了研究。相对于非超积累菌，羽扇豆根和地上部的硒积累速率较高，而硫酸盐或高S预处理对硒的竞争抑制较小。海藻对硒的吸收速率(1h)是非超积累菌的三到四倍，并且不受100倍的过量硫酸盐的影响，过量的硫酸盐使海藻和芥菜对硒的吸收分别减少100%和40%。实时逆转录聚合酶链式反应显示硫酸盐转运体SULTR1；2(根内流)和SULTR2；1(转位)在金针菇中结构性上调，但SULTR1；1表达降低(根内流)。潜在的机制可能包括SULTR1；2和SULTR2；1的过度表达，这可能另外进化出了对硒酸盐比硫酸盐更强的特异性。
Stanleya pinnata not only hyperaccumulates selenium (Se) to 0.5% of its dry weight, but also exhibits higher tissue Se-to-sulfur (S) ratios than other species and its surroundings.To investigate the mechanisms underlying this Se enrichment, we compared S. pinnata with the nonhyperaccumulators S. elata and Brassica juncea for selenate uptake in long-(9 d) and short-term (1 h) assays, using different concentrations of selenate and competitor sulfate. Different sulfate pre-treatments (0, 0.5, 5 mM, 3 d) were also tested for effects on selenate uptake and sulfate transporters' expression.Relative to nonhyperaccumulators, S. pinnata showed higher rates of root and shoot Se accumulation and less competitive inhibition by sulfate or by high-S pretreatment. The selenate uptake rate for S. pinnata (1 h) was three-to four-fold higher than for nonhyperaccumulators, and not significantly affected by 100-fold excess sulfate, which reduced selenate uptake by 100% in S. elata and 40% in B. juncea. Real-time reverse transcription PCR indicated constitutive upregulation in S. pinnata of sulfate transporters SULTR1;2 (root influx) and SULTR2;1 (translocation), but reduced SULTR1;1 expression (root influx).In S. pinnata, selenate uptake and translocation rates are constitutively elevated and relatively sulfate-independent. Underlying mechanisms likely include overexpression of SULTR1;2 and SULTR2;1, which may additionally have evolved enhanced specificity for selenate over sulfate.