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245	1	0	_aCompetition between uptake of ammonium and potassium in barley and Arabidopsis roots: molecular mechanisms and physiological consequences
490	0		_vJournal of Experimental Botany, 61, p.2303-2315, 2010
520	3		_aPlants can use ammonium (NH1 4 ) as the sole nitrogen source, but at high NH1 4 concentrations in the root medium, particularly in combination with a low availability of K1, plants suffer from NH1 4 toxicity. To understand the role of K1 transporters and non-selective cation channels in K1/NH1 4 interactions better, growth, NH1 4 and K1 accumulation and the specific fluxes of NH1 4 , K1, and H1 were examined in roots of barley (Hordeum vulgare L.)and Arabidopsis seedlings. Net fluxes of K1 and NH1 4 were negatively correlated, as were their tissue concentrations, suggesting that there is direct competition during uptake. pharmacological treatments with the K1 transport inhibitors tetraethyl ammonium (TEA1)and gadolinium (Gd31)reduced NH1 4 influx, and the addition of TEA1 alleviated the NH1 4 -induced depression of root growth in germinating Arabidopsis plants. Screening of a barley root cDNA library in a yeast mutant lacking all NH1 4 and K1 uptake proteins through the deletion of MEP1-3 and TRK1 and TRK2 resulted in the cloning of the barley K1 transporter HvHKT2;1. Further analysis in yeast suggested that HvHKT2;1, AtAKT1, and AtHAK5 transported NH1 4 , and that K1 supplied at increasing concentrations competed with this NH1 4 transport. On the other hand, uptake of K1 by AtHAK5, and to a lesser extent via HvHKT2;1 and AtAKT1, was inhibited by increasing concentrations of NH1 4 . Together, the results of this study show that plant K1 transporters and channels are able to transport NH1 4 . Unregulated NH1 4 uptake via these transporters may contribute to NH1 4 toxicity at low K1 levels, and may explain the alleviation of NH1 4 toxicity by K1.
650	1	4	_aAMMONIUM TOXICITY
650	1	4	_aARABIDOPSIS
650	1	4	_aBARLEY
650	1	4	_aCOMPETITION
650	1	4	_aGADOLINIUM
650	1	4	_aPOTASSIUM NUTRITION
650	1	4	_aTETRAETHYL AMMONIUM
700	1	2	_aHoopen, F.
700	1	2	_aCuin, T.
700	1	2	_aPedas, P.
700	1	2	_aHegelund, J.N.
700	1	2	_aShabala, S.
700	1	2	_aSchjoerring, J.K.
700	1	2	_aJahn, T.P.
856	4	0	_uhttps://drive.google.com/file/d/1Bh_km_u_Dx4UwvO3Xho7SH4kV6uniyxq/view?usp=drivesdk _zPara ver el documento ingresa a Google con tu cuenta: @cicy.edu.mx
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