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ARS Home » Northeast Area » Ithaca, New York » Robert W. Holley Center for Agriculture & Health » Plant, Soil and Nutrition Research » Research » Publications at this Location » Publication #349607
Title: Aluminum-activated root malate and citrate exudation is independent of NIP1;2-facilitated root-cell-wall aluminum removal in Arabidopsis

Author
item WANG, YUQI - Cornell University
item CAI, YANFEI - South China Agricultural University
item CAO, YU - South China Agricultural University
item Liu, Jiping

Submitted to: Plant Signaling and Behavior
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/21/2017
Publication Date: 1/17/2018
Citation: Wang, Y., Cai, Y., Cao, Y., Liu, J. 2018. Aluminum-activated root malate and citrate exudation is independent of NIP1;2-facilitated root-cell-wall aluminum removal in Arabidopsis. Plant Signaling and Behavior. 13(1). https://doi.org/10.1080/15592324.2017.1422469.
DOI: https://doi.org/10.1080/15592324.2017.1422469

Interpretive Summary: In Arabidopsis, aluminum (Al) exclusion from the root is mainly facilitated by Al-activated root malate and citrate exudation through the ALMT1 malate transporter and the MATE citrate transporter, respectively. However, the nature of an internal Al tolerance mechanism remains largely unknown. In a recent study, we showed that NIP1;2 facilitates Al-malate transport from the root cell wall into the root symplasm and subsequent root-to-shoot translocation and thus NIP1;2 plays key roles in Al detoxification and internal tolerance in Arabidopsis. We discovered that the NIP1;2-mediated Al removal from the root cell wall requires a functional ALMT1-mediated malate exudation system, which allows the formation of an Al-malate complex in the root cell wall. Thus, a coordinated function between the exclusion and the internal resistance mechanisms, linked by the ALMT1-mediated root malate exudation and the NIP1;2-mediated Al uptake system, is critical for Al resistance in Arabidopsis.

Technical Abstract: Our previous work has demonstrated that NIP1;2 is necessary for Al-malate complex to be transported into cytosol for the final storage in leaves. However, it remains unclear whether NIP1;2 is a prerequisite for ALMT-mediated malate exudation under Al stress. In this present work. We further confirmed that NIP1;2 is able to transoport Al-malate into yeast. Loss-of-function mutant nip1;2 had no effect on ALMT1 expression and malate exudation under Al stress, thus suggesting that ALMT1-mediated malate exudation is independent of NIP1;2, though this process is required for NIP1;2-mediated Al resistance.