Department of Physics, Chemistry and Biology (IFM)

Plants are living photosynthetic organisms able to use sunlight energy to synthesize carbohydrates from inorganic carbon (CO₂). Arbuscular mycorrhiza (AM) symbiosis is the widest distributed type of mycorrhization, as it concerns 90 % of the land plants and more than 80 % of the cultivated crops. AM symbiosis is based on mutual exchange of nutrients. This means that nutrients, harvested by the fungus are exchanged for sugars, produced by the plant through photosynthetic activity in leaf chloroplasts. AM establishment occurs after seed germination. During AM symbiosis, the fungal hyphae invades the root through an appressorium from which intercellular hyphae development occurs and after that forming the arbuscule inside the cell, where the signaling and metabolite exchange occurs.

AM symbiosis allow the plant to benefit from a better supply in nutrients, mainly inorganic phosphate (Pi). Therefore, it is not surprising that the presence of significant amounts of Pi in the soil negatively impacts the symbiosis establishment. Using the model legume Medicago truncatula in association with fungi of the Glomeromycota taxon, identification of marker genes for the appressorium and arbuscule root colonisation stages has contributed to the understanding of the mechanism of AM establishment. AM symbiosis leads to increased demand for photosynthetic activity.