Diversidad de hongos micorrízicos orquideoides pertenecientes a la familia Ceratobasidiaceae

Abstract

Abstract: Orchids depend on mycorrhizal fungi for their development, with the family Ceratobasidiaceae being key. This study analyzed the diversity of these fungi in 12 species of epiphytic orchids from southern Ecuador, identifying 33 Operational Taxonomic Units (OTUs) through sequencing the ITS2 region of ribosomal DNA. A threshold of 1% was determined for delimiting OTUs within the genus Ceratobasidium. The results showed that Stelis superbiens was the orchid with the greatest diversity of associated fungi (22 OTUs), followed by Cyrtochilum myanthum (13 OTUs). Of the identified OTUs, only six could be assigned to the genus Ceratobasidium, while the rest were classified in other genera such as Rhizoctonia and Thanatephorus or had no clear classification. Phylogenetic analysis, using a 1% sequence difference threshold, revealed that the ITS2 marker has limitations in differentiating closely related species, suggesting the need to employ additional genetic markers in future studies. These findings are an important contribution to the conservation of tropical orchids and underscore the high specificity that characterizes these symbiotic interactions.