Abstract
Recently, two K+-transport cDNAs, KAT1 and AKT1, were cloned in Arabidopsis thaliana. These cDNAs had structural similarities to K+ channel genes in animals, and also conferred the ability for growth on micromolar levels of K+ when expressed in K+ transport-defective yeast mutants. In this study, we examined the possibility that KAT1 encodes the high-affinity K+ transport system that has been previously characterized in plant roots, by studying the concentration-dependent kinetics of K+ transport for KAT1 expressed in Xenopus oocytes and Saccharomyces cerevisiae. In both organisms, the K+ transport system encoded by KAT1 yielded Michaelis-Menten kinetics with a high Km for K+ (35 mM in oocytes, 0.6 mM in yeast cells). Furthermore, Northern analysis indicated that KAT1 is expressed primarily in the Arabidopsis shoot. These results strongly suggest that the system encoded by KAT1 is not a root high-affinity K+ transporter.
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© 1993 Springer Science+Business Media Dordrecht
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Kochian, L.V., Garvin, D.F., Shaff, J.E., Chilcott, T.C., Lucas, W.J. (1993). Towards an understanding of the molecular basis of plant K+ transport: characterization of cloned K+ transport cDNAs. In: Barrow, N.J. (eds) Plant Nutrition — from Genetic Engineering to Field Practice. Developments in Plant and Soil Sciences, vol 54. Springer, Dordrecht. https://doi.org/10.1007/978-94-011-1880-4_18
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DOI: https://doi.org/10.1007/978-94-011-1880-4_18
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