Adaptation of H+-Pumping and Plasma Membrane H+ ATPase Activity in Proteoid Roots of White Lupin under Phosphate Deficiency

• Feng Yan

  Institute of Plant Nutrition, Interdisciplinary Research Center, Justus Liebig University, Heinrich-Buff-Ring 26–32, D–35392 Giessen, Germany

• Yiyong Zhu

  Institute of Plant Nutrition, Interdisciplinary Research Center, Justus Liebig University, Heinrich-Buff-Ring 26–32, D–35392 Giessen, Germany

• Caroline Müller

  Institute of Plant Nutrition, Interdisciplinary Research Center, Justus Liebig University, Heinrich-Buff-Ring 26–32, D–35392 Giessen, Germany

• Christian Zörb

  Institute of Plant Nutrition, Interdisciplinary Research Center, Justus Liebig University, Heinrich-Buff-Ring 26–32, D–35392 Giessen, Germany

• Sven Schubert

  Institute of Plant Nutrition, Interdisciplinary Research Center, Justus Liebig University, Heinrich-Buff-Ring 26–32, D–35392 Giessen, Germany

Abstract

White lupin (Lupinus albus) is able to adapt to phosphorus deficiency by producing proteoid roots that release a huge amount of organic acids, resulting in mobilization of sparingly soluble soil phosphate in rhizosphere. The mechanisms responsible for the release of organic acids by proteoid root cells, especially the trans-membrane transport processes, have not been elucidated. Because of high cytosolic pH, the release of undissociated organic acids is not probable. In the present study, we focused on H+ export by plasma membrane H+ ATPase in active proteoid roots. In vivo, rhizosphere acidification of active proteoid roots was vanadate sensitive. Plasma membranes were isolated from proteoid roots and lateral roots from P-deficient and -sufficient plants. In vitro, in comparison with two types of lateral roots and proteoid roots of P-sufficient plants, the following increase of the various parameters was induced in active proteoid roots of P-deficient plants: (a) hydrolytic ATPase activity, (b) V  max andK  m, (c) H+ ATPase enzyme concentration of plasma membrane, (d) H+-pumping activity, (e) pH gradient across the membrane of plasmalemma vesicles, and (f) passive H+ permeability of plasma membrane. In addition, lower vanadate sensitivity and more acidic pH optimum were determined for plasma membrane ATPase of active proteoid roots. Our data support the hypothesis that in active proteoid root cells, H+ and organic anions are exported separately, and that modification of plasma membrane H+ ATPase is essential for enhanced rhizosphere acidification by active proteoid roots.

Journal

• Plant Physiology

  Plant Physiology 129 (1), 50-63, 2002-05-01

  Oxford University Press (OUP)

Keywords

• Plant Science
• Genetics
• Physiology

Details

• CRID: 1362825896309345408
• NII Article ID: 80015436393
• DOI: 10.1104/pp.010869
• ISSN: 15322548
• ISSN: 00320889
• Web Site: http://academic.oup.com/plphys/article-pdf/129/1/50/38688336/plphys_v129_1_50.pdf
• Data Source:
  • Crossref
  • CiNii Articles