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Ion currents involved in early Nod factor response in Medicago sativa root hairs: a discontinuous single‐electrode voltage‐clamp study
Author(s) -
Kurkdjian Armen,
Bouteau François,
Pennarun AnneMarie,
Convert Monique,
Cornel Daniel,
Rona JeanPierre,
Bousquet Ulrike
Publication year - 2000
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.2000.00714.x
Subject(s) - depolarization , root hair , biophysics , ion channel , nod factor , chemistry , ion , patch clamp , voltage clamp , membrane potential , electrode , ion current , medicago sativa , biology , biochemistry , botany , root nodule , receptor , nitrogen fixation , organic chemistry , nitrogen , gene
Summary Nod factor [NodRm‐IV(Ac,S)], isolated from the bacterium Rhizobium meliloti , induces a well‐known depolarization in Medicago sativa (cv Sitel) root hairs. Analysis of this membrane response using the discontinuous single‐electrode voltage‐clamp technique (dSEVC) shows that anion channel, K + channel and H + ‐ATPase pump currents are involved in young growing root hairs. The early Nod‐factor‐induced depolarization is due to increase of the inward ion current and inhibition of the H + pump. It involved an instantaneous inward anion current (IIAC) and/or a time‐dependent inward K + current (IRKC). These two ion currents are then down‐regulated while the H + pump is stimulated, allowing long‐term rectification of the membrane potential ( E m ). Our results support the idea that the regulation of inward current plays a primary role in the Nod‐factor‐induced electrical response, the nature of the ions carried by these currents depending on the activated anion and/or K + channels at the plasma membrane.