Influence of Fungal Auxin on Host Plant Gene Expression During Ectomycorrhiza Formation

Abstract

Mycorrhiza is a symbiotic association between the plants and fungi that colonize the cortical tissue of roots during periods of active plant growth. The term mycorrhiza, "fungus root", was first used by Frank, (1885) to describe, long-lived association between plant roots and fungal mycelium. Since then we have learned that the vast majority of land plants form symbiotic associations with fungi. An estimated 95% of all plant species belong to genera that characteristically form mycorrhizae. Given the dominance of mycotrophy in the large majority of ecosystems and of its function and structure, Harley (1989), defined mycorrhiza as "Joint or dual organs (roots, rhizomes, or thalli) of many, perhaps most, higher plants inhabited by symbiotic fungi". This association comprises of a plant root and fungal hyphae, which serve as the interface between the two partners. They are widespread symbiotic associations including soil fungi and the roots of most land plants. They have been of primary importance in the evolution of land plants (Harley and Smith 1983; Simon et al., 1993) and are key component of plant and fungal communities (Allen, 1991). The association is characterized by the movement of plant-produced carbon to the fungus and fungal-acquired nutrients to the plant.