Repeat variants for the SbMATE transporter protect sorghum roots from aluminum toxicity by transcriptional interplay in and .

Acidic soils, where aluminum (Al) toxicity is a major agricultural constraint, are globally widespread and are prevalent in developing countries. In sorghum, the root citrate transporter SbMATE confers Al tolerance by protecting root apices from toxic Al, but can exhibit reduced expression when introgressed into different lines. We show that allele-specific transactivation occurs and is caused by factors located away from Using expression-QTL mapping and expression genome-wide association mapping, we establish that transcription is controlled in a bipartite fashion, primarily in but also in Multiallelic promoter transactivation and ChIP analyses demonstrated that intermolecular effects on expression arise from a WRKY and a zinc finger-DHHC transcription factor (TF) that bind to and -activate the promoter.

Incomplete transfer of accessory loci influencing SbMATE expression underlies genetic background effects for aluminum tolerance in sorghum.

Impaired root development caused by aluminum (Al) toxicity is a major cause of grain yield reduction in crops cultivated on acid soils, which are widespread worldwide. In sorghum, the major Al-tolerance locus, AltSB , is due to the function of SbMATE, which is an Al-activated root citrate transporter. Here we performed a molecular and physiological characterization of various AltSB donors and near-isogenic lines harboring various AltSB alleles.