NIP1;2 is a plasma membrane-localized transporter mediating aluminum uptake, translocation, and tolerance in <i>Arabidopsis</i>

Abstract

Significance Aluminum (Al) toxicity is a major constraint for crops grown on acid soils. Various plant species have adopted an Al exclusion/avoidance mechanism and/or internal tolerance mechanisms to ameliorate Al toxicity. In Arabidopsis , the root organic acid exudation-based Al exclusion mechanism has been well characterized; however, no evidence for an internal Al tolerance mechanism has been reported. Here we identify NIP1;2 as an Al-malate transporter involved in Al removal from root cell walls and root-to-shoot Al translocation. We report that the NIP1;2-mediated Al-malate transport is dependent on Al-activated root malate efflux mediated by ALMT1 in Arabidopsis . Taken together, our findings demonstrate the importance of the coordination between Al exclusion and internal Al detoxification mechanisms in Al tolerance in Arabidopsis .