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Potassium nutrition of ectomycorrhizal P inus pinaster : overexpression of the H ebeloma cylindrosporum H c T rk1 transporter affects the translocation of both K + and phosphorus in the host plant
Author(s) -
Garcia Kevin,
Delteil Amandine,
Conéjéro Geneviève,
Becquer Adeline,
Plassard Claude,
Sentenac Hervé,
Zimmermann Sabine
Publication year - 2014
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.12603
Subject(s) - potassium , transporter , phosphorus , biology , chemistry , biochemistry , botany , gene , organic chemistry
Summary Mycorrhizal associations are known to improve the hydro‐mineral nutrition of their host plants. However, the importance of mycorrhizal symbiosis for plant potassium nutrition has so far been poorly studied. We therefore investigated the impact of the ectomycorrhizal fungus H ebeloma cylindrosporum on the potassium nutrition of P inus pinaster and examined the involvement of the fungal potassium transporter H c T rk1. H c T rk1 transcripts and proteins were localized in ectomycorrhizas using in situ hybridization and EGFP translational fusion constructs. Importantly, an overexpression strategy was performed on a H . cylindrosporum endogenous gene in order to dissect the role of this transporter. The potassium nutrition of mycorrhizal pine plants was significantly improved under potassium‐limiting conditions. Fungal strains overexpressing H c T rk1 reduced the translocation of potassium and phosphorus from the roots to the shoots of inoculated plants in mycorrhizal experiments. Furthermore, expression of H c T rk1 and the phosphate transporter H c PT 1.1 were reciprocally linked to the external inorganic phosphate and potassium availability. The development of these approaches provides a deeper insight into the role of ectomycorrhizal symbiosis on host plant K + nutrition and in particular, the K + transporter H c T rk1. The work augments our knowledge of the link between potassium and phosphorus nutrition via the mycorrhizal pathway.