Plants and arbuscular mycorrhizal fungi: an evolutionary-developmental perspective

Arbuscular mycorrhizas (AMs) are widespread symbiotic associations that are commonly described as the result of co-evolution events between fungi and plants where both partners benefit from the reciprocal nutrient exchange. Here, we review data from fossil records, characterizations of AM fungi in basal plants and live cell imaging of angiosperm colonization processes from an evolutionary-developmental perspective. The uniformity of plant cell responses to AM colonization in haploid gametophytes and diploid sporophytes, in non-root organs, and throughout many seed plant clades highlights the ancient origin of the interaction and suggests the existence of common molecular and cellular processes. The possibility that pre-existing mechanisms involved in plant cell division were recruited by plants to accommodate AM fungi is discussed.