TY - JOUR

T1 - Plasma membrane H+-ATPase-dependent citrate exudation from cluster roots of phosphate-deficient white lupin

AU - Tomasi, Nicola

AU - Kretzschmar, Tobias

AU - Espen, Luca

AU - Weisskopf, Laure

AU - Fuglsang, Anja Thoe

AU - Palmgren, Michael

AU - Neumann, Günter

AU - Varanini, Zeno

AU - Pinton, Roberto

AU - Martinoia, Enrico

AU - Cesco, Stefano

PY - 2009

Y1 - 2009

N2 - ABSTRACTWhite lupin (Lupinus albus L.) is able to grow on soils withsparingly available phosphate (P) by producing specializedstructures called cluster roots.To mobilize sparingly solubleP forms in soils, cluster roots release substantial amounts ofcarboxylates and concomitantly acidify the rhizosphere.Therelationship between acidification and carboxylate exudationis still largely unknown. In the present work,we studiedthe linkage between organic acids (malate and citrate) andproton exudations in cluster roots of P-deficient white lupin.After the illumination started, citrate exudation increasedtransiently and reached a maximum after 5 h. This effectwas accompanied by a strong acidification of the externalmedium and alkalinization of the cytosol, as evidenced by in vivo nuclear magnetic resonance (NMR) analysis. Fusicoccin,nuclear magnetic resonance (NMR) analysis. Fusicoccin,an activator of the plasmamembrane (PM)H+-ATPase, stimulated citrate exudation, whereas vanadate, an inhibitorof the H+-ATPase, reduced citrate exudation. The burst of citrate exudation was associated with an increase in expressionof theLHA1PMH+-ATPase gene,an increased amount of H+-ATPase protein, a shift in pH optimum of the enzymeand post-translational modification of an H++-ATPase protein involving binding of activating 14-3-3 protein.Takentogether, our results indicate a close link in cluster roots ofP-deficient white lupin between the burst of citrate exudationand PM H+-ATPase-catalysed proton efflux.

AB - ABSTRACTWhite lupin (Lupinus albus L.) is able to grow on soils withsparingly available phosphate (P) by producing specializedstructures called cluster roots.To mobilize sparingly solubleP forms in soils, cluster roots release substantial amounts ofcarboxylates and concomitantly acidify the rhizosphere.Therelationship between acidification and carboxylate exudationis still largely unknown. In the present work,we studiedthe linkage between organic acids (malate and citrate) andproton exudations in cluster roots of P-deficient white lupin.After the illumination started, citrate exudation increasedtransiently and reached a maximum after 5 h. This effectwas accompanied by a strong acidification of the externalmedium and alkalinization of the cytosol, as evidenced by in vivo nuclear magnetic resonance (NMR) analysis. Fusicoccin,nuclear magnetic resonance (NMR) analysis. Fusicoccin,an activator of the plasmamembrane (PM)H+-ATPase, stimulated citrate exudation, whereas vanadate, an inhibitorof the H+-ATPase, reduced citrate exudation. The burst of citrate exudation was associated with an increase in expressionof theLHA1PMH+-ATPase gene,an increased amount of H+-ATPase protein, a shift in pH optimum of the enzymeand post-translational modification of an H++-ATPase protein involving binding of activating 14-3-3 protein.Takentogether, our results indicate a close link in cluster roots ofP-deficient white lupin between the burst of citrate exudationand PM H+-ATPase-catalysed proton efflux.

U2 - 10.1111/j.1365-3040.2009.01938.x

DO - 10.1111/j.1365-3040.2009.01938.x

M3 - Journal article

C2 - 19183296

VL - 32

SP - 465

EP - 475

JO - Plant, Cell and Environment

JF - Plant, Cell and Environment

SN - 0140-7791

IS - 5

ER -