Nature Genetics 39, 1156 - 1161 (2007)
Published online: 26 August 2007 | doi:10.1038/ng2074

A gene in the multidrug and toxic compound extrusion (MATE) family confers aluminum tolerance in sorghum

Jurandir V Magalhaes1,6, Jiping Liu2, Claudia T Guimarães1, Ubiraci G P Lana1, Vera M C Alves1, Yi-Hong Wang2,5, Robert E Schaffert1, Owen A Hoekenga2, Miguel A Piñeros2, Jon E Shaff2, Patricia E Klein3, Newton P Carneiro1, Cintia M Coelho1,5, Harold N Trick4 & Leon V Kochian2,6

Crop yields are significantly reduced by aluminum toxicity on highly acidic soils, which comprise up to 50% of the world's arable land1, 2, 3. Candidate aluminum tolerance proteins include organic acid efflux transporters, with the organic acids forming non-toxic complexes with rhizosphere aluminum1, 4. In this study, we used positional cloning to identify the gene encoding a member of the multidrug and toxic compound extrusion (MATE) family, an aluminum-activated citrate transporter, as responsible for the major sorghum (Sorghum bicolor) aluminum tolerance locus, AltSB5. Polymorphisms in regulatory regions of AltSB are likely to contribute to large allelic effects, acting to increase AltSB expression in the root apex of tolerant genotypes. Furthermore, aluminum-inducible AltSB expression is associated with induction of aluminum tolerance via enhanced root citrate exudation. These findings will allow us to identify superior AltSB haplotypes that can be incorporated via molecular breeding and biotechnology into acid soil breeding programs, thus helping to increase crop yields in developing countries where acidic soils predominate.