Expressing ScACR3 in Rice Enhanced Arsenite Efflux and Reduced Arsenic Accumulation in Rice Grains
Expressing ScACR3 in Rice Enhanced Arsenite Efflux and Reduced Arsenic Accumulation in Rice Grains
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DOI：
10.1093/pcp/pcr161
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发表时间：
2012-01-01
影响因子：
4.9
通讯作者：
Fujiwara, Toru
中科院分区：
文献类型：
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作者：
Duan, Guilan;Kamiya, Takehiro;Fujiwara, Toru
稻米中砷(As)的积累对稻米消费量高的人群构成严重的健康风险。ScAcr3p对亚砷酸盐[As(III)]的挤出作用是酿酒酵母砷解毒的主要机制。然而，ScAcr3p同源物在高等植物中不存在，包括水稻。本研究将ScACR3基因导入水稻，并在花椰菜花叶病毒(CaMV)35S启动子控制下表达。在转基因品系中，地上部和根部的As浓度比野生型低约30%，而As的转运因子在转基因品系和野生型之间相似。转基因植株的根系外排活性显著高于野生型植株。在10亩砷酸根[As(V)]处理24 h内，表达ScACR3的植物根系将80%的As(V)排出到外源As(III)中，而野生型植物的根系排出了50%的As(V)。此外，通过将含As的水稻植株置于缺As溶液中24 h，表达ScACR3的植株将约30%的As挤入外源溶液中，而野生型植株约有15%的As被分泌到外源溶液中。重要的是，ScACR3的表达显著减少了AS在稻草和籽粒中的积累。在含As(III)灌溉的淹水土壤中，转基因植株稻壳和糙米中的As含量分别比野生型降低了30%和20%。这项研究报告了一种潜在的策略，通过在作物中表达异源基因来减少食物链中砷的积累。
Arsenic (As) accumulation in rice grain poses a serious health risk to populations with high rice consumption. Extrusion of arsenite [As(III)] by ScAcr3p is the major arsenic detoxification mechanism in Saccharomyces cerevisiae. However, ScAcr3p homolog is absent in higher plants, including rice. In this study, ScACR3 was introduced into rice and expressed under the control of the Cauliflower mosaic virus (CaMV) 35S promoter. In the transgenic lines, As concentrations in shoots and roots were about 30% lower than in the wild type, while the As translocation factors were similar between transgenic lines and the wild type. The roots of transgenic plants exhibited significantly higher As efflux activities than those of the wild type. Within 24 h exposure to 10 mu M arsenate [As(V)], roots of ScACR3-expressing plants extruded 80% of absorbed As(V) to the external solution as As(III), while roots of the wild type extruded 50% of absorbed As(V). Additionally, by exposing the As-containing rice plants to an As-lacking solution for 24 h, about 30% of the total As derived from pre-treatment was extruded to the external solution by ScACR3-expressing plants, while about 15% of As was extruded by wild-type plants. Importantly, ScACR3 expression significantly reduced As accumulation in rice straws and grains. When grown in flooded soil irrigated with As(III)-containing water, the As concentration in husk and brown rice of the transgenic lines was reduced by 30 and 20%, respectively, compared with the wild type. This study reports a potential strategy to reduce As accumulation in the food chain by expressing heterologous genes in crops.