ATP binding cassette proteins ABCG37 and ABCG33 function as potassium-independent cesium uptake carriers in Arabidopsis roots
ATP binding cassette proteins ABCG37 and ABCG33 function as potassium-independent cesium uptake carriers in Arabidopsis roots
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DOI：
10.1016/j.molp.2021.02.002
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发表时间：
2021-04-05
期刊：
影响因子：
27.5
通讯作者：
Rahman, Abidur
中科院分区：
文献类型：
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作者：
Ashraf, Mohammad Arif;Akihiro, Takashi;Rahman, Abidur
由于核事故在土壤中积累的放射性铯是一个主要的环境问题。铯(Cs+)的运输过程与植物不可缺少的营养钾(K+)密切相关，因为它们都属于化学性质相似的I族碱金属。到目前为止，大多数被描述为Cs+转运蛋白的转运蛋白都直接或间接地与K+有关。本研究采用生理学、遗传学、细胞生物学和根系吸收相结合的方法，确定了两种三磷酸腺苷结合盒(ABC)蛋白ABCG37和ABCG33作为Cs+内流的促进剂。ABCG37的功能获得突变体(abcg37-1)对Cs+诱导的根生长抑制表现出更高的敏感性，而ABCG33和ABCG37的双基因敲除突变体(abcg33-1abcg37-2)表现出抗性，而单一功能缺失突变体ABCG33和ABCG37对Cs+的响应没有任何变化。在植物中，短期放射性Cs~+摄取试验以及异源体系中生长和摄取试验证实ABCG33和ABCG37是Cs~+摄取载体。转化ABCG33和ABCG37的酵母细胞在没有K+的情况下不能生长，证明ABCG33和ABCG37对Cs+的吸收不依赖于K+。总而言之，这项工作确定了两个ABC蛋白作为新的Cs+内流载体，它们的作用是冗余的，不依赖于K+吸收途径。
Radiocesium accumulated in the soil by nuclear accidents is amajor environmental concern. The transport process of cesium (Cs+) is tightly linked to the indispensable plant nutrient potassium (K+) as they both belong to the group I alkali metals with similar chemical properties. Most of the transporters that had been characterized to date as Cs+ transporters are directly or indirectly linked to K+. Using a combinatorial approach of physiology, genetics, cell biology, and root uptake assay, here we identified two ATP-binding cassette (ABC) proteins, ABCG37 and ABCG33, as facilitators of Cs+ influx. A gain-of-function mutant of ABCG37 (abcg37-1) showed increased sensitivity to Cs+-induced root growth inhibition, while the double knockout mutant of ABCG33 and ABCG37 (abcg33-1abcg37-2) showed resistance, whereas the single loss-of-function mutants of ABCG33 and ABCG37 did not show any alteration in Cs+ response. In planta short-term radioactive Cs+-uptake assay along with growth and uptake assays in a heterologous system confirmed ABCG33 and ABCG37 as Cs+-uptake carriers. Potassium response and content were unaffected in the double-mutant background and yeast cells lacking potassium-uptake carriers transformed with ABCG33 and ABCG37 failed to grow in the absence of K+, confirming that Cs+ uptake by ABCG33 and ABCG37 is independent of K+. Collectively, this work identified two ABC proteins as new Cs+-influx carriers that act redundantly and independent of the K+-uptake pathway.