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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 #344408
Title: AhFRDL1-mediated citrate secretion contributes to adaptation to iron deficiency and aluminum stress in peanuts

Author
item QUI, WEI - China Agricultural University
item WANG, NANQI - China Agricultural University
item DAI, JING - China Agricultural University
item WANG, TIANQI - China Agricultural University
item KOCHIAN, LEON - University Of Saskatchewan
item Liu, Jiping
item ZUO, YUANMEI - China Agricultural University

Submitted to: Journal of Experimental Botany
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/2/2019
Publication Date: 3/17/2019
Citation: Qui, W., Wang, N., Dai, J., Wang, T., Kochian, L.V., Liu, J., Zuo, Y. 2019. AhFRDL1-mediated citrate secretion contributes to adaptation to iron deficiency and aluminum stress in peanuts. Journal of Experimental Botany. 70(10):2873-2886. https://doi.org/10.1093/jxb/erz089.
DOI: https://doi.org/10.1093/jxb/erz089

Interpretive Summary: Although citrate transporters in the MATE family have been demonstrated to facilitate either Fe translocation or Al tolerance in plant, none of them have been identified to confer both biological functions. Here we demonstrate that AhFRDL1, a member of the MATE family in peanut (Arachis hypogaea L.), functions as a citrate transporter facilitating both Fe translocation and Al tolerance. Electrophysiological studies indicated that the plasma-membrane-localized AhFRDL1 facilitates Al-activated citrate efflux in Xenopus oocytes. AhFRDL1 expression is mainly localized to the root stele, and this expression is enhanced by both Fe deficiency and Al stress. Interestingly, under Al stress, AhFRDL1 expression is expanded from the stele to the entire cross section in the root tip region. Moreover, overexpression of AhFRDL1 restored root growth of the AtMATE knock-out or AtMATE/AtALMT1 double-knock-out mutants under Al stress. Functional studies indicated that overexpression of AhFRDL1 in Arabidopsis frd3 mutant line rescued the hypersensitive phenotypes of the mutant plants to Fe deficiency. Knocking down AhFRDL1 expression in peanut root resulted in reduced citrate and Fe concentrations in the root xylem sap and new leaves, respectively, suggesting that the AhFRDL1 citrate transporter facilitates Fe translocation from the root to the shoot via citrate release into the root xylem. Taken together, our results suggest that AhFRDL1 facilitates both Fe translocation and Al resistance in peanut.

Technical Abstract: We have identified and characterized a citrate transporter, AhFRDL1, of the MATE family from peanut. AhFRDL1 is localized to the plasma membrane and facilitate citrate efflux when expressed in oocyte. AhFRDL1 expression is mainly localized to the root stele, and this expression is enhanced by both Fe deficiency and Al stress. We demonstrated that AhFRL1 facilitate Fe translocation and Al resistance, a unique character of the citrate transporter in the MATE family.