Abstract
Background: Mycorrhizal fungi are essential for the growth and development of all orchid species. In most Cypripediumspecies, the dominant orchid mycorrhizal fungi belong to the family Tulasnellaceae. In Mesoamerica, considered the center of origin of the genus, there are three species belonging to section Irapeana, that constitutes a sister clade to the rest of the genus, differentiated from their morphological, geographical, and ecological characteristics.
Questions and / or Hypotheses: The orchid mycorrhizal fungi species associated with Mesoamerican Cypripediumspecies in different populations show the same specificity as previously reported.
Studied species: Cypripedium irapeanum and Cypripedium molle (Orchidaceae).
Study site and dates: Mexico, Veracruz, Puebla, Morelos and Oaxaca states of Mexico, 2019.
Methods: We analyzed the orchid mycorrhizal fungal community by the amplification and sequencing of fungal internal transcribed spacer (ITS2 for Illumina MiSeq).
Results: Identified orchid mycorrhizal fungal families (Tulasnellaceae and Sebacinaceae) as well as molecular species (Operational Taxonomic Units) were closely related amongst the populations even on different habitats and plant ages. Adult plants have a wider spectrum of Operational Taxonomic Units than plantlets, suggesting changes in specificity during life cycle; also, some isolates and Operational Taxonomic Units belong to clades not reported with other Cypripedium species in the world.
Conclusions: These findings strengthen the ecological and phylogenetic differences of Mesoamerican slipper orchids with the rest of the Cypripedium sections and increase the information available for the conservation of these highly endangered species.