<i>Hc</i> TOK1 participates in the maintenance of K ⁺ homeostasis in the ectomycorrhizal fungus <i>Hebeloma cylindrosporum</i> , which is essential for the symbiotic K ⁺ nutrition of <i>Pinus pinaster</i>

Abstract

Most land plants rely on root symbioses to complement or improve their mineral nutrition. Recent researches have put forward that mycorrhizal fungi efficiently absorb and transfer potassium (K⁺) from the soil to host plant roots, but the molecular mechanisms involved are not completely elucidated yet. We have recently revealed that K⁺ is likely released from the fungal Hartig net to the plant by TOK channels in the ectomycorrhizal model Hebeloma cylindrosporum - Pinus pinaster. H. cylindrosporum harbours three TOK members. Herein, we report that one of them, HcTOK1, has similar features than the yeast ScTOK1. Moreover, we propose a role for this channel in the transport of K⁺ from the medium to ectomycorrhizal roots under K⁺ starvation.