Arbuscular mycorrhizas (AMs) are some of the most widespread symbioses on earth. More than 80% of plants are known to establish AM associations with fungi from the Glomeromycota, which improves the mineral nutrition of plants, particularly of phosphorus (Smith and Read, 2008). In return, plants provide sugar to the fungal symbionts. The establishment of an AM symbiosis proceeds as a series of genetically controlled steps and commences with a pre-symbiotic molecular crosstalk leading to reciprocal perception (Nadal and Paszkowski, 2013). The fungus makes contact with the root surface via a hyphopodium only if successful recognition occurs. The hyphopodium then penetrates into the root leading to the formation of arbuscules, or sites of nutrient exchange (Bonfante and Requena, 2011 and Nadal and Paszkowski, 2013).