TY  - JOUR
A1  - Hürter, Anna-Lena
A1  - Fort, Sébastian
A1  - Cottaz, Sylvain
A1  - Hedrich, Rainer
A1  - Geiger, Dietmar
A1  - Roelfsema, M. Rob G.
T1  - Mycorrhizal lipochitinoligosaccharides (LCOs) depolarize root hairs of Medicago truncatula
JF  - PLoS ONE
N2  - Arbuscular Mycorrhiza and Root Nodule Symbiosis are symbiotic interactions with a high benefit for plant growth and crop production. Thus, it is of great interest to understand the developmental process of these symbioses in detail. We analysed very early symbiotic responses of Medicago truncatula root hair cells, by stimulation with lipochitinoligosaccharides specific for the induction of nodules (Nod-LCOs), or the interaction with mycorrhiza (Myc-LCOs). Intracellular micro electrodes were used, in combination with Ca\(^{2+}\) sensitive reporter dyes, to study the relations between cytosolic Ca\(^{2+}\) signals and membrane potential changes. We found that sulfated Myc- as well as Nod-LCOs initiate a membrane depolarization, which depends on the chemical composition of these signaling molecules, as well as the genotype of the plants that were studied. A successive application of sulfated Myc-LCOs and Nod-LCOs resulted only in a single transient depolarization, indicating that Myc-LCOs can repress plasma membrane responses to Nod-LCOs. In contrast to current models, the Nod-LCO-induced depolarization precedes changes in the cytosolic Ca\(^{2+}\) level of root hair cells. The Nod-LCO induced membrane depolarization thus is most likely independent of cytosolic Ca\(^{2+}\) signals and nuclear Ca\(^{2+}\) spiking.
KW  - depolarization
KW  - Medicago truncatula
KW  - lipochitinoligosaccharides
Y1  - 2018
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-176841
VL  - 13
IS  - 5
ER  - 
TY  - JOUR
A1  - Dindas, Julian
A1  - Scherzer, Sönke
A1  - Roelfsema, M. Rob G.
A1  - Meyer, Katharina von
A1  - Müller, Heike M.
A1  - Al-Rasheid, K. A. S.
A1  - Palme, Klaus
A1  - Dietrich, Petra
A1  - Becker, Dirk
A1  - Bennett, Malcolm J.
A1  - Hedrich, Rainer
T1  - AUX1-mediated root hair auxin influx governs SCFTIR1/AFB-type Ca2+ signaling
JF  - Nature Communications
N2  - Auxin is a key regulator of plant growth and development, but the causal relationship between hormone transport and root responses remains unresolved. Here we describe auxin uptake, together with early steps in signaling, in Arabidopsis root hairs. Using intracellular microelectrodes we show membrane depolarization, in response to IAA in a concentration- and pH-dependent manner. This depolarization is strongly impaired in aux1 mutants, indicating that AUX1 is the major transporter for auxin uptake in root hairs. Local intracellular auxin application triggers Ca2+ signals that propagate as long-distance waves between root cells and modulate their auxin responses. AUX1-mediated IAA transport, as well as IAA- triggered calcium signals, are blocked by treatment with the SCFTIR1/AFB - inhibitor auxinole. Further, they are strongly reduced in the tir1afb2afb3 and the cngc14 mutant. Our study reveals that the AUX1 transporter, the SCFTIR1/AFB receptor and the CNGC14 Ca2+ channel, mediate fast auxin signaling in roots.
KW  - auxin
KW  - permeation and transport
Y1  - 2018
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-225368
VL  - 9
ER  -