HIGH DIVERSITY OF ARBUSCULAR MYCORRHIZAL FUNGI IN TWO FORESTRY ECOSYSTEMS FROM CENTRAL AND NORTHERN COSTA RICA

Abstract

Background: Arbuscular mycorrhizal fungi (AMF) generate a symbiotic relationship with most terrestrial plants, influencing the dynamics and functioning of ecosystems. There are few studies on the diversity of these fungi associated with forest species and in different types of ecosystems. The objective of this study was to characterize the diversity and structure of AMF communities associated with Cordia alliodora and Swietenia macrophylla in two forestry ecosystems with different types of management in Costa Rica. For this purpose, rhizosphere and soil samples were collected from 10 trees at random, spores and sporocarps were isolated and characterized, AMF abundance, richness and diversity were determined, and a physicochemical analysis of the soil was carried out. Results: Fifty-seven AMF morphospecies belonging to five orders, 10 families and 15 genera were identified, with a predominance of Diversisporales and Glomerales; we report 15 new geographic records of AMF increasing the richness to 76 species and by 24% the Glomeromycota’s richness in Costa Rica. There were no significant differences in total spore abundance between the two forest species, however, there were significant differences in the modes of formation and species composition. Conclusions: The alpha diversity analysis showed that rare species largely explain the differences between the sites, and the AMF community structure was influenced by edaphic factors such as pH and available phosphorus content. These types of studies highlight the importance of considering the identity and diversity of AMF associated with forest species of commercial interest and ecological importance in different types of ecosystems.