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A de novo synthesis citrate transporter, Vigna umbellata multidrug and toxic compound extrusion, implicates in Al‐activated citrate efflux in rice bean ( Vigna umbellata ) root apex
Author(s) -
YANG XIAO YING,
YANG JIAN LI,
ZHOU YUAN,
PIÑEROS MIGUEL A.,
KOCHIAN LEON V.,
LI GUI XIN,
ZHENG SHAO JIAN
Publication year - 2011
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/j.1365-3040.2011.02410.x
Subject(s) - efflux , transporter , citric acid , biology , biochemistry , vigna , gene , botany
Al‐activated organic acid anion efflux from roots is an important Al resistance mechanism in plants. We have conducted homologous cloning and isolated Vigna umbellata multidrug and toxic compound extrusion ( VuMATE ), a gene encoding a de novo citrate transporter from rice bean. Al treatment up‐regulated VuMATE expression in the root apex, but neither in the mature root region nor in the leaf. The degree of up‐regulation of VuMATE was both partially Al concentration and time dependent, consistent with the delay in the onset of the Al‐induced citrate efflux in rice bean roots. While La 3+ moderately induced VuMATE expression, Cd 2+ and Cu 2+ did not induce the expression. Electrophysiological analysis of Xenopus oocytes expressing VuMATE indicated this transporter can mediate significant anion efflux across the plasma membrane. [ 14 C]citrate efflux experiments in oocytes demonstrated that VuMATE is a H + ‐dependent citrate transporter. In addition, expression of VuMATE in transgenic tomato resulted in increased Al resistance, which correlated with an enhanced citrate efflux. Taken together, these findings suggest that VuMATE is a functional homolog of the known citrate transporters in sorghum, barley, maize and Arabidopsis . The similarities and differences of all the known citrate transporters associated with Al stress in the MATE family are also discussed.