Submitted to: American Society of Plant Physiologists Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 9/29/1996
Publication Date: N/A
Technical Abstract: An Arabidopsis thaliana mutant with increased resistance to aluminum (alr104) has been isolated in our laboratories. The mutation was mapped to a single locus on chromosome 4. Using map based cloning, the corresponding gene is currently being identified. The roots of the mutant plant were shown to release higher levels of citrate into the rhizosphere compared to wild type roots. Citrate is an effective Al3+ chelator and might thereby prevent the uptake of aluminum into the root apex. Also, measurements of ionic fluxes with a vibrating pH microelectrode showed an increased proton influx at the root apex. This proton influx should raise the rhizosphere pH and reduce the concentration of the toxic Al3+ species available in the rhizosphere. We are currently studying both citrate synthesis and transport in this mutant to determine the physiological basis for the increased citrate efflux.