Climbing to the top: how arbuscular mycorrhizal fungi colonize leaf litter

Limited information is available about arbuscular mycorrhizal fungi (AMF) in leaf litter, but studies reporting AMF in litter have gained prominence. The factors that drive these organisms to colonize litter, as well as the AMF species that occur under such conditions are not yet understood. The identification of AMF species colonizing this substrate has been overlooked due to a lack of information and difficulties in recovering AMF from leaf litter. It has been suggested that these fungi might prefer to colonize litter in the early stage of decomposition, especially low litter quality. Furthermore, to date, no study has identified the AMF species colonizing leaf litter, obscuring the AMF diversity, ecology, and their role play during leaf litter decomposition. In light of this, leaf litter samples were collected from three Brazilian Atlantic Forest sites and analyzed using both morphological and molecular approaches. The decomposition stage, litter quality, and edaphic factors drove AMF colonization in leaf litter. Diversispora varaderana , Funneliformis caledonius , F. geosporus , Glomus spinuliferum , and Rhizoglomus irregulare were here reported for the first time colonizing leaf litter. Among these, D. varaderana and F. caledonius were recorded for the first time in Brazil and in the Brazilian Atlantic Forest, respectively. Therefore, leaf litter emerged as a promising habitat, complementing soil, for studying AMF diversity and investigating their ecological role in decomposition and biotechnological applications.