Mycorrhizas in South American Ericaceae

Mycorrhizal symbioses (mycorrhizas) of Ericaceae, including ericoid mycorrhiza (ErM), have been mainly studied in the Northern Hemisphere, although the highest diversity of ericaceous plants is located in the Southern Hemisphere, where several regions remain largely unexplored. One of them is South America, which harbors a remarkably high diversity of Ericaceae (691 species and 33 genera) in a wide range of environmental conditions, and a specific mycorrhizal type called cavendishioid. In this review, we compile all available information on mycorrhizas of Ericaceae in South America. We report data on the mycorrhizal type and fungal diversity in 17 and 11 ericaceous genera, respectively. We show that South American Ericaceae exhibit a high diversity of habitats and life forms and that some species from typical ErM subfamilies may also host arbuscular mycorrhiza. Also, a possible geographical pattern in South American ErM fungal communities is suggested, with Sebacinales being the dominant mycorrhizal partners of the Andean clade species from tropical mountains, while archetypal ErM fungi are common partners in southern South America species. The gathered information challenges some common assumptions about ErM and suggests that focusing on understudied regions would improve our understanding of the evolution of mycorrhizal associations in this intriguing family.