02515naa a2200265 a 450000100080000000500110000800800410001902400420006010000120010224501750011426000090028952016620029865300090196065300230196965300220199265300150201465300260202965300280205565300290208365300240211270000210213670000140215770000160217177300620218714917912018-05-30       2009    bl uuuu     u00u1 u    #d7 a10.1111/j.1365-313X.2008.03696.x2DOI1 aLIU, J.  aAluminum-activated citrate and malate transporters from the MATE and ALMT families function independently to confer Arabidopsis aluminum tolerance.h[electronic resource]  c2009  aAluminum-activated root malate and citrate exudation play an important role in plant Al tolerance. This paper characterizes AtMATE, a homolog of the recently discovered sorghum and barley Al-tolerance genes, shown here to encode an Al-activated citrate transporter in Arabidopsis. Together with the previously characterized Al-activated malate transporter, AtALMT1, this discovery allowed us to examine the relationship in the same species between members of the two gene families for which Al-tolerance genes have been identified. AtMATE is expressed primarily in roots and is induced by Al. An AtMATE T-DNA knockdown line exhibited very low AtMATE expression and Al-activated root citrate exudation was abolished. The AtALMT1 AtMATE double mutant lacked both Al-activated root malate and citrate exudation and showed greater Al sensitivity than the AtALMT1 mutant. Therefore, although AtALMT1 is a major contributor to Arabidopsis Al tolerance, AtMATE also makes a significant but smaller contribution. The expression patterns of AtALMT1 and AtMATE and the profiles of Al-activated root citrate and malate exudation are not affected by the presence or absence of the other gene. These results suggest that AtALMT1-mediated malate exudation and AtMATE-mediated citrate exudation evolved independently to confer Al tolerance in Arabidopsis. However, a link between regulation of expression of the two transporters in response to Al was identified through work on STOP1, a transcription factor that was previously shown to be necessary for AtALMT1 expression. Here we show that STOP1 is also required for AtMATE expression and Al-activated citrate exudation.  aALMT  aAluminum tolerance  aAluminum toxicity  aMulti-drug  aOrganic cid exudation  aPlasma membrane protein  aToxic compound extrusion  aTransporter protein1 aMAGALHAES, J. V.1 aSHAFF, J.1 aKOCHIAN, L.  tThe Plant Journal, Maldengv. 57, n. 3, p. 389-399, 2009.