Plasma membrane H+-ATPase-dependent citrate exudation from cluster roots of phosphate-deficient white lupin
Articolo
Data di Pubblicazione:
2009
Citazione:
Plasma membrane H+-ATPase-dependent citrate exudation from cluster roots of phosphate-deficient white lupin / N. TOMASI, T. KRETZSCHMAR, L. ESPEN, L. WEISSKOPF, A. T. FUGLSANG,
M. G. PALMGREN, G. NEUMANN, Z. VARANINI, R. PINTON, E. MARTINOIA, S. CESCO. - In: PLANT, CELL AND ENVIRONMENT. - ISSN 0140-7791. - 32:5(2009), pp. 465-475.
Abstract:
White lupin (Lupinus albus L.) is able to grow on soils with
sparingly available phosphate (P) by producing specialized
structures called cluster roots.To mobilize sparingly soluble
P forms in soils, cluster roots release substantial amounts of
carboxylates and concomitantly acidify the rhizosphere.The
relationship between acidification and carboxylate exudation
is still largely unknown. In the present work,we studied
the linkage between organic acids (malate and citrate) and
proton exudations in cluster roots of P-deficient white lupin.
After the illumination started, citrate exudation increased
transiently and reached a maximum after 5 h. This effect
was accompanied by a strong acidification of the external
medium and alkalinization of the cytosol, as evidenced by in
vivo nuclear magnetic resonance (NMR) analysis. Fusicoccin,
an activator of the plasmamembrane (PM)H+-ATPase,
stimulated citrate exudation, whereas vanadate, an inhibitor
of the H+-ATPase, reduced citrate exudation. The burst of
citrate exudation was associated with an increase in expression
of theLHA1PMH+-ATPase gene,an increased amount
of H+-ATPase protein, a shift in pH optimum of the enzyme
and post-translational modification of an H+-ATPase
protein involving binding of activating 14-3-3 protein.Taken
together, our results indicate a close link in cluster roots of
P-deficient white lupin between the burst of citrate exudation
and PM H+-ATPase-catalysed proton efflux.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
Lupinus albus ; carboxylate release ; malate ;
organic acids ; pH ; phosphorus ; proton pump ; rhizosphere ; root exudates
Elenco autori:
N. TOMASI, T. KRETZSCHMAR, L. ESPEN, L. WEISSKOPF, A. T. FUGLSANG,
M. G. PALMGREN, G. NEUMANN, Z. VARANINI, R. PINTON, E. MARTINOIA, S. CESCO
Link alla scheda completa: