Facultative symbiosis with a saprotrophic soil fungus promotes potassium uptake in American sweetgum trees.
Plant Cell Environ
; 44(8): 2793-2809, 2021 08.
Article
em En
| MEDLINE
| ID: mdl-33764571
ABSTRACT
Several species of soil free-living saprotrophs can sometimes establish biotrophic symbiosis with plants, but the basic biology of this association remains largely unknown. Here, we investigate the symbiotic interaction between a common soil saprotroph, Clitopilus hobsonii (Agaricomycetes), and the American sweetgum (Liquidambar styraciflua). The colonized root cortical cells were found to contain numerous microsclerotia-like structures. Fungal colonization led to increased plant growth and facilitated potassium uptake, particularly under potassium limitation (0.05 mM K+ ). The expression of plant genes related to potassium uptake was not altered by the symbiosis, but colonized roots contained the transcripts of three fungal genes with homology to K+ transporters (ACU and HAK) and channel (SKC). Heterologously expressed ChACU and ChSKC restored the growth of a yeast K+ -uptake-defective mutant. Upregulation of ChACU transcript under low K+ conditions (0 and 0.05 mM K+ ) compared to control (5 mM K+ ) was demonstrated in planta and in vitro. Colonized plants displayed a larger accumulation of soluble sugars under 0.05 mM K+ than non-colonized plants. The present study suggests reciprocal benefits of this novel tree-fungus symbiosis under potassium limitation mainly through an exchange of additional carbon and potassium between both partners.
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Base de dados:
MEDLINE
Assunto principal:
Potássio
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Simbiose
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Raízes de Plantas
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Liquidambar
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Agaricales
Idioma:
En
Ano de publicação:
2021
Tipo de documento:
Article