Orchid Mycorrhizas in South America: Tropical and Subtropical Ecosystems

South America is undoubtedly the cradle of orchid diversity. However, few aspects of the biology of this plant group have been explored in the region. Orchids establish an important relationship with fungi that supply them with nutrients in the early stages of development to stimulate the germination of their tiny seeds. These fungi are called orchid mycorrhizal fungi (OMF), and their interaction with orchids forms a particular group of mycorrhizae: the orchid mycorrhiza (OM). In this chapter, we present the advances of the research conducted in South America, which explores some aspects of this interesting interaction. We have noticed that most studies on OM are academic documents deposited in university library repositories or published in local scientific journals. About half of the studies have focused on determining the diversity of OMF associated with a few orchid species of interest. Studies of phylogeny, morphological, and symbiotic seed germination are other of the main topics addressed. Research on ultrastructure and community ecology is hardly representative, while evolutionary implications, mutualistic networks, and metabolic aspects are the least explored topics. We encourage collaborations with the international scientific community to continue investigating complex questions that allow us to understand the role of mycorrhizas in the evolutionary success of tropical orchids. Moreover, we believe that it is important to propose attractive research that generates interest not only in the academic community but also in ordinary people who have traditionally been related to orchids (e.g., growers) in order to develop the enormous potential of the region in this field.