image: Proposed model suggested by researchers, where ABCG33 and ABCG37 uptake cesium inside the plant cell in a potassium-independent manner view more
Credit: Abidur Rahman
In recent time, HBO's highly acclaimed and award-winning miniseries Chernobyl highlighted the horror of nuclear power plant accident, which happened in Ukraine in 1986. It is not a fictional series just on TV. As we had seen such a catastrophic nuclear power plant accident in 2011 again caused by natural disaster, Tsunami, in Japan. Both historical nuclear power plant accidents released tons of radioactive cesium to the environment. Consequently, the radioactive cesium found their way to the surrounding land, river, into the plants and animal feed, and eventually to our food cycle and ecosystem. The more detrimental part is their half-life, as 137Cs has half-life of ~30 years. So, it is going to be a serious agricultural, economic, and health problem for such a long time without effective actions. Plant biologists use the technique call phytoremediation to use the plant or manipulate the plant genetically to take up toxic components from soil or make crop plants resilient to such contaminated soil. Over the years, scientists tried to find cesium transporters in plants, and till now mostly ended up with several potassium transporters. It is not surprising if someone thinks about the basic chemistry and periodic table of elements we learnt in the high school. Cesium (Cs) resides in the same group with potassium (K). But potassium is abundant in soil and important for plant growth and development. As a result, manipulating potassium transporter to regulate cesium uptake will cause problem for plant growth in general. In contrast to potassium, cesium is not abundant in the soil and it is toxic for plants. So, the idea of finding potassium-independent cesium transporter, which will transport cesium without affecting potassium, is a long waited one.
Recently, plant biologist Dr. Abidur Rahman's group from Iwate University, Japan in a collaboration with Dr. Keitaro Tanoi from the University of Tokyo and Dr. Takashi Akihiro from the Shimane University reported two potassium-independent cesium transporters, where these two transporters dedicatedly uptake cesium inside the plant without affecting potassium. Their finding has been published recently in the top tier plant-specific journal from Cell press, Molecular Plant. They have shown that two ATP Binding Cassette (also known as ABC transporter in general and evolutionary abundant across the kingdom) proteins, ABCG33 and ABCG37, uptake cesium inside the cell.
"This study highlights how we can solve the agricultural issues around us with basic research and why the basic research should be funded". This study also demonstrates the power of collaborations to answer the scientific questions" said the group leader Dr. Abidur Rahman.
"Arif Ashraf,one of the lead authors who conducted the study as part of his graduate study in the Iwate University and currently a postdoc at the University of Massachusetts Amherst, said that how the basic plant biology research can solve real-life problem around us" He added, "In this study, we combined plant physiology, molecular biology, cell biology with in planta transport assay using radioactive cesium, and heterologous system such as yeast, as well".
These transporters are first step forward towards the basic understanding of potassium-independent cesium transport in plant and promise for future bioremediation. Based on their current finding and proposed model, it suggests that possibly more potassium-independent cesium transporters are yet to discover in plant. Abidur lab is working on finding other unknown cesium transporters. Deciphering the basic mechanism and finding more transporters in this regard will help to develop phytoremediation technique possible and translate this mechanism from model plant to crop plants, as these reported transporters are also conserved in crop plants and other species.
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Journal
Molecular Plant