Sugar for my honey

Carbohydrate partitioning in ectomycorrhizal symbiosis

verfasst von

Uwe Nehls, Nina Grunze, Martin Willmann, Marlis Reich, Helge Küster

Abstract

Simple, readily utilizable carbohydrates, necessary for growth and maintenance of large numbers of microbes are rare in forest soils. Among other types of mutualistic interactions, the formation of ectomycorrhizas, a symbiosis between tree roots and certain soil fungi, is a way to overcome nutrient and carbohydrate limitations typical for many forest ecosystems. Ectomycorrhiza formation is typical for trees in boreal and temperate forests of the northern hemisphere and alpine regions world-wide. The main function of this symbiosis is the exchange of fungus-derived nutrients for plant-derived carbohydrates, enabling the colonization of mineral nutrient-poor environments. In ectomycorrhizal symbiosis up to 1/3 of plant photoassimilates could be transferred toward the fungal partner. The creation of such a strong sink is directly related to the efficiency of fungal hexose uptake at the plant/fungus interface, a modulated fungal carbohydrate metabolism in the ectomycorrhiza, and the export of carbohydrates towards soil growing hyphae. However, not only the fungus but also the plant partner increase its expression of hexose importer genes at the plant/fungus interface. This increase in hexose uptake capacity of plant roots in combination with an increase in photosynthesis may explain how the plant deals with the growing fungal carbohydrate demand in symbiosis and how it can restrict this loss of carbohydrates under certain conditions to avoid fungal parasitism.

Externe Organisation(en)

Eberhard Karls Universität Tübingen
Universität Bielefeld

Typ

Übersichtsarbeit

Journal

PHYTOCHEMISTRY

Band

68

Seiten

82-91

Anzahl der Seiten

10

ISSN

0031-9422

Publikationsdatum

01.01.2007

Publikationsstatus

Veröffentlicht

Peer-reviewed

Ja

ASJC Scopus Sachgebiete

Biochemie, Molekularbiologie, Pflanzenkunde, Gartenbau

Elektronische Version(en)

https://doi.org/10.1016/j.phytochem.2006.09.024 (Zugang: Unbekannt)