Influx and accumulation of Cs+ by the akt1 mutant of Arabidopsis thaliana (L.) Heynh. lacking a dominant K+ transport system

Escobar-Guti�rrez, Abraham J.; Willey, Neil J.; Escobar-Gutierrez, A; Broadley, Martin R.; Willey, Neil; Bowen, Helen C.; White, Philip J.

Abstract

An extensive literature reports that Cs+, an environmental contaminant, enters plant cells through K+ transport systems. Several recently identified plant K+ transport systems are permeable to Cs+. Permeation models indicate that most Cs+ uptake into plant roots under typical soil ionic conditions will be mediated by voltage-insensitive cation (VIC) channels in the plasma membrane and not by the inward rectifying K+ (KIR) channels implicated in plant K nutrition. Cation fluxes through KIR channels are blocked by Cs+. This paper tests directly the hypothesis that the dominant KIR channel in plant roots (AKT1) does not contribute significantly to Cs+ uptake by comparing Cs+ uptake into wild-type and the akt1 knockout mutant of Arabidopsis thaliana (L.) Heynh. Wild-type and akt1 plants were grown to comparable size and K+ content on agar containing 10 mM K+. Both Cs+ influx to roots of intact plants and Cs+ accumulation in roots and shoots were identical in wild-type and akt1 plants. These data indicate that AKT1 is unlikely to contribute significantly to Cs+ uptake by wild-type Arabidopsis from 'single-salt' solutions. The influx of Cs+ to roots of intact wild-type and akt1 plants was inhibited by I mM Ba2+, Ca2+ and La3+, but not by 10 μM Br-cAMP. This pharmacology resembles that of VIC channels and is consistent with the hypothesis that VIC channels mediate most Cs+ influx under 'single-salt' conditions.

• Journal Article Type: Article
• Publication Date: Jan 1, 2001
• Deposit Date: Feb 23, 2015
• Journal: Journal of Experimental Botany
• Print ISSN: 0022-0957
• Electronic ISSN: 1460-2431
• Publisher: Oxford University Press (OUP)
• Peer Reviewed: Peer Reviewed
• Volume: 52
• Issue: 357
• Pages: 839-844
• DOI: https://doi.org/10.1093/jexbot/52.357.839
• Keywords: caesium, cation channel, potassium, transport phytoremediation
• Public URL: https://uwe-repository.worktribe.com/output/1087285
• Publisher URL: http://dx.doi.org/10.1093/jexbot/52.357.839
• Contract Date: Nov 15, 2016