Building a functional repertoire of ion channels active at the plasma membrane of apical regions of medicago truncatula legume root hairs
2018
Guo, Man Yuan | Wang, Limin | Sentenac, Herve | Véry, Anne-Aliénor
Root hairs are elongated epidermal cells essential for the acquisition of mineral nutrients by the plant. In legumes, they are also the seat of initiation of symbiotic interactions with N2‐fixing rhizobia. In these plants, early ionic signals initiated at the root hair plasma membrane, involving changes in H+ , Ca2+ , anions and K + ion fluxes and resulting in transient depolarization of the cell membrane, are triggered as initial responses to perception of the signaling Nod factors secreted by the rhizobial partners present in the rhizosphere. Here, we aimed at building a repertoire of ion channel activities present at root hair plasma membrane of the model legume M. truncatula , which could be implicated in these early signaling events leading to symbiosis establishment. Apical spheroplasts of plasma membrane of young growing root hairs, recovered through cell‐wall laser ablation, were used in patch‐clamp experiments. Six ionic conductances selective for Ca2+ , K+ or anions, involved in ion influx and/or effluxes, were identified and their sensitivity to NF checked. This provides a first sketch of the set of transport systems involved in the Nod‐factor‐triggered electrical signals, paving the way to future confirmation through reverse genetics on corresponding candidate genes in this sequenced model legume.
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