AtKUP/HAK/KT9, a K+Transporter fromArabidopsis thaliana, Mediates Cs+Uptake inEscherichia coli

Although cesium is known to be absorbed by plants, the pathway by which cesium enters has not been identified. We found that the AtKUP/HAK/KT9 gene from Arabidopsis thaliana was functionally expressed in a potassium transport-deficient Escherichia coli mutant. AtKUP/HAK/KT9 mediated potassium uptake as well as cesium transport. We found that AtKUP/HAK/KT9 might be involved in the pathway in questions.