Symbiotic Proteomics — State of the Art in Plant–Mycorrhizal Fungi Interactions

Mycorrhizae are symbiotic associations between soil fungi belonging to diverse taxa and the roots of about 90% of all terrestrial plant species. The mutualistic nature of these symbioses is based on the nutritional exchanges between the partners. However, the benefits to the plant partner are not limited to an improved mineral nutrition because they also include a general increase in stress tolerance and health. Because of these benefits, mycorrhizae are of great interest in sustainable agriculture and forestry. In the past few years, the development of high-throughput molecular tools, in addition to the advancements in microscopy techniques, has allowed us to gain a deeper insight on the molecular mechanisms underlying the establishment and functioning of these symbioses. In this chapter, we focus on the use of proteomic tools to better understand the molecular bases of cell communication and the regulation of developmental and metabolic pathways in mycorrhizal associations

Zinc ions alter morphology and chitin deposition in an ericoid fungus

A sterile mycelium PS IV, an ascomycete capable of establishing ericoid mycorrhizas, was used to investigate how zinc ions affect the cellular mechanisms of fungal growth. Asignificant reduction of the fungal biomass was observed in the presence of millimolar zinc concentrations; this mirrored conspicuous changes in hyphal morphology which led to apical swellings and increased branching in the subapical parts. Specific probes for fluorescence and electron microscopy localised chitin, the main cell wall polysaccharide, on the inner part of the fungal wall and on septa in control specimens. In Zn-treated mycelium, hyphal walls were thicker and a more intense chitin labelling was detected on the transverse walls. Aquantitative assay showed a significant increase in the amount of chitin in metal- treated hyphae