Phytochelatins play key roles for the difference in root arsenic accumulation of different Triticum aestivum cultivars in comparison with arsenate uptake kinetics and reduction
Phytochelatins play key roles for the difference in root arsenic accumulation of different Triticum aestivum cultivars in comparison with arsenate uptake kinetics and reduction
复制标题
与砷酸盐吸收动力学和还原相比，植物螯合素对不同小麦品种根部砷积累的差异起着关键作用
DOI：
10.1016/j.chemosphere.2017.02.017
复制
发表时间：
2017
期刊：
影响因子：
8.8
通讯作者：
Qing Sheng Cai
中科院分区：
文献类型：
--
作者：
Gao Ling Shi;Lai Qing Lou;Dao Jun Li;Zhu Bing Hu;Qing Sheng Cai
在以往的研究中，我们发现砷（As）在小麦（Triticum aestivumL.）不同小麦品种间差异显著，耐As（V）小麦品种根系积累As的能力更强。然而，差异的原因仍不清楚。以4个高砷（As）积累和低砷积累的小麦品种（MM 45和FM 8）为材料，研究了小麦根系吸收As（V）动力学与As积累的关系。MM 45和HM 29还用于检测小麦幼苗中As（V）还原能力和非蛋白巯基（半胱氨酸[Cys]、谷胱甘肽[GSH]和植物螯合素[PC]）浓度。MM 45细胞的米氏常数（Km）最小，内流速率（Vmax）最大。其他3个品种间Km值无显著差异。在MM 45和HM 29之间没有观察到As（V）还原能力的差异。10 μM As（V）对小麦幼苗根中GSH和PC 2的含量有明显的诱导作用，尤其是对MM 45的诱导作用最强。γ-谷氨酰半胱氨酸合成酶的特异性抑制剂丁硫酰亚砜亚胺（BSO）可完全抑制GSH和PC的合成。BSO显著降低了小麦幼苗对砷的耐性，降低了根中砷的积累，但增加了地上部砷的积累。BSO处理下，MM 45和HM 29的As含量差异不显著。GSH和PCs是不同小麦品种根系积累砷和耐性差异的原因。
In the previous studies, we have found that arsenic (As) accumulation in roots of bread wheat (Triticum aestivumL.) seedlings were significantly different among different wheat cultivars, and As(V) tolerant wheat cultivars have much higher capacities of root As accumulation. However, the reason for the difference remains unclear. Four wheat cultivars with high (MM45 and FM8) or low (QF1 and HM29) levels of arsenic (As) accumulation were selected to investigate the relationship between root As(V) uptake kinetics and root As accumulation. MM45 and HM29 were also used to examine As(V) reduction ability and non-protein thiol (cysteine [Cys], glutathione [GSH], and phytochelatins [PCs]) concentrations in wheat seedlings. MM45 had the lowest Michaelis–Menten constant (Km) and maximum influx rate (Vmax). No difference in theKmvalues was found among the three other cultivars. No difference in As(V) reduction capacity was observed between MM45 and HM29. GSH and PC2were significantly induced by 10 μM As(V) in roots of wheat seedlings, particularly in MM45. Synthesis of GSH and PCs was completely suppressed in the presence ofl-buthionine sulfoximine (BSO), a specific inhibitor of γ-glutamylcysteine synthetase. BSO markedly decreased the As tolerance of wheat seedlings and decreased the accumulation of As in roots, but increased As accumulation in shoots. No significant difference in As concentrations was found between MM45 and HM29 under the BSO treatment. GSH and PCs are the reason why As accumulation and As(V) tolerance differ in roots of different wheat cultivars.