Nod signal-induced plasma membrane potential changes in alfalfa root hairs are differentially sensitive to structural modifications of the lipochitooligosaccharide

Hubert H. Felle, É. Kondorosi, Ádám Kondorosi, Michael Schultze

Research output: Article

99 Citations (Scopus)

Abstract

Lipochitooligosaccharide Nod signals are important determinants of host specificity in the Rhizobium-legume symbiosis. The most rapid response of plant cells to the R. meliloti Nod signal NodRm-IV(C16:2,S) reported so far is the depolarization of the plasma membrane potential in alfalfa root hairs. In order to investigate whether this response may be part of a specific signal transduction cascade involved in the nodulation process, its specificity was studied with respect to host-specific modifications of the lipochitooligosaccharide. Five different Nod factors displaying different degrees of activity in inducing root hair deformation or cortical cell divisions on alfalfa were tested. The ability of the Nod factors to elicit plasma membrane depolarization correlated well with their activity in the bioassays. Removal of the sulfate group (NodRm-IV(C16:2)) led to inactivation of the Nod factor. An increase in the length of the chitooligosaccharide backbone (NodRm-V(C16:2,S)) or saturation of the acyl chain (NodRm-IV(C16:0,S)) resulted in severely reduced activity. In contrast, the O-acetyl group at the non-reducing terminus in NodRm-IV(Ac,C16:2,S), which confers substantially higher activity in long-term bioassays, did not enhance plasma membrane depolarization significantly in comparison with the non-O-acetylated factor. Thus, the rapid plasma membrane response is differentially sensitive to various structural motifs of the lipochitooligosaccharide. These data suggest that the different substitueras modifying the basic Nod factor structure may have distinct functions, not all of them contributing to the interaction with a putative receptor in root hair cells. However, the overall specificity of the membrane depolarization for the cognate Nod factors raises the possibility that it is involved in a Nod signal transduction pathway.

Original languageEnglish
Pages (from-to)939-947
Number of pages9
JournalPlant Journal
Volume7
Issue number6
Publication statusPublished - jún. 1995

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Medicago sativa
root hairs
membrane potential
Membrane Potentials
alfalfa
plasma membrane
Cell Membrane
Biological Assay
signal transduction
Signal Transduction
Melilotus
bioassays
chitooligosaccharides
Ensifer meliloti
Rhizobium
Symbiosis
Host Specificity
Plant Cells
host specificity
nodulation

ASJC Scopus subject areas

  • Plant Science

Cite this

@article{881cba490a0f4bdf950e96df6b1124a1,
title = "Nod signal-induced plasma membrane potential changes in alfalfa root hairs are differentially sensitive to structural modifications of the lipochitooligosaccharide",
abstract = "Lipochitooligosaccharide Nod signals are important determinants of host specificity in the Rhizobium-legume symbiosis. The most rapid response of plant cells to the R. meliloti Nod signal NodRm-IV(C16:2,S) reported so far is the depolarization of the plasma membrane potential in alfalfa root hairs. In order to investigate whether this response may be part of a specific signal transduction cascade involved in the nodulation process, its specificity was studied with respect to host-specific modifications of the lipochitooligosaccharide. Five different Nod factors displaying different degrees of activity in inducing root hair deformation or cortical cell divisions on alfalfa were tested. The ability of the Nod factors to elicit plasma membrane depolarization correlated well with their activity in the bioassays. Removal of the sulfate group (NodRm-IV(C16:2)) led to inactivation of the Nod factor. An increase in the length of the chitooligosaccharide backbone (NodRm-V(C16:2,S)) or saturation of the acyl chain (NodRm-IV(C16:0,S)) resulted in severely reduced activity. In contrast, the O-acetyl group at the non-reducing terminus in NodRm-IV(Ac,C16:2,S), which confers substantially higher activity in long-term bioassays, did not enhance plasma membrane depolarization significantly in comparison with the non-O-acetylated factor. Thus, the rapid plasma membrane response is differentially sensitive to various structural motifs of the lipochitooligosaccharide. These data suggest that the different substitueras modifying the basic Nod factor structure may have distinct functions, not all of them contributing to the interaction with a putative receptor in root hair cells. However, the overall specificity of the membrane depolarization for the cognate Nod factors raises the possibility that it is involved in a Nod signal transduction pathway.",
author = "Felle, {Hubert H.} and {\'E}. Kondorosi and {\'A}d{\'a}m Kondorosi and Michael Schultze",
year = "1995",
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T1 - Nod signal-induced plasma membrane potential changes in alfalfa root hairs are differentially sensitive to structural modifications of the lipochitooligosaccharide

AU - Felle, Hubert H.

AU - Kondorosi, É.

AU - Kondorosi, Ádám

AU - Schultze, Michael

PY - 1995/6

Y1 - 1995/6

N2 - Lipochitooligosaccharide Nod signals are important determinants of host specificity in the Rhizobium-legume symbiosis. The most rapid response of plant cells to the R. meliloti Nod signal NodRm-IV(C16:2,S) reported so far is the depolarization of the plasma membrane potential in alfalfa root hairs. In order to investigate whether this response may be part of a specific signal transduction cascade involved in the nodulation process, its specificity was studied with respect to host-specific modifications of the lipochitooligosaccharide. Five different Nod factors displaying different degrees of activity in inducing root hair deformation or cortical cell divisions on alfalfa were tested. The ability of the Nod factors to elicit plasma membrane depolarization correlated well with their activity in the bioassays. Removal of the sulfate group (NodRm-IV(C16:2)) led to inactivation of the Nod factor. An increase in the length of the chitooligosaccharide backbone (NodRm-V(C16:2,S)) or saturation of the acyl chain (NodRm-IV(C16:0,S)) resulted in severely reduced activity. In contrast, the O-acetyl group at the non-reducing terminus in NodRm-IV(Ac,C16:2,S), which confers substantially higher activity in long-term bioassays, did not enhance plasma membrane depolarization significantly in comparison with the non-O-acetylated factor. Thus, the rapid plasma membrane response is differentially sensitive to various structural motifs of the lipochitooligosaccharide. These data suggest that the different substitueras modifying the basic Nod factor structure may have distinct functions, not all of them contributing to the interaction with a putative receptor in root hair cells. However, the overall specificity of the membrane depolarization for the cognate Nod factors raises the possibility that it is involved in a Nod signal transduction pathway.

AB - Lipochitooligosaccharide Nod signals are important determinants of host specificity in the Rhizobium-legume symbiosis. The most rapid response of plant cells to the R. meliloti Nod signal NodRm-IV(C16:2,S) reported so far is the depolarization of the plasma membrane potential in alfalfa root hairs. In order to investigate whether this response may be part of a specific signal transduction cascade involved in the nodulation process, its specificity was studied with respect to host-specific modifications of the lipochitooligosaccharide. Five different Nod factors displaying different degrees of activity in inducing root hair deformation or cortical cell divisions on alfalfa were tested. The ability of the Nod factors to elicit plasma membrane depolarization correlated well with their activity in the bioassays. Removal of the sulfate group (NodRm-IV(C16:2)) led to inactivation of the Nod factor. An increase in the length of the chitooligosaccharide backbone (NodRm-V(C16:2,S)) or saturation of the acyl chain (NodRm-IV(C16:0,S)) resulted in severely reduced activity. In contrast, the O-acetyl group at the non-reducing terminus in NodRm-IV(Ac,C16:2,S), which confers substantially higher activity in long-term bioassays, did not enhance plasma membrane depolarization significantly in comparison with the non-O-acetylated factor. Thus, the rapid plasma membrane response is differentially sensitive to various structural motifs of the lipochitooligosaccharide. These data suggest that the different substitueras modifying the basic Nod factor structure may have distinct functions, not all of them contributing to the interaction with a putative receptor in root hair cells. However, the overall specificity of the membrane depolarization for the cognate Nod factors raises the possibility that it is involved in a Nod signal transduction pathway.

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