Aluminum (Al) toxicity is a major limiting factor for plant growth and crop production in acidic soils. The plasma membrane H+-ATPase is involved in regulating resistance to Al via enhanced citrate exudation by soybean roots under Al stress. In their investigation of the processes underlying this resistance.
Wang et al. find that enhanced citrate exudation and increased soybean root growth under Al stress were associated with auxin (IAA) accumulation in soybean roots. They show that IAA-mediated increases in Al-induced citrate exudation in soybean were linked with upregulation of the citrate transporter gene (GmMATE) and activation of the root-cell plasma membrane H-ATPase.