Molecular survey of arbuscular mycorrhizal fungi associated with Tolpis on three Canarian islands (Asteraceae)

Abstract

The diversity of arbuscular mycorrhizal (AM) fungi in island systems is poorly understood. Molecular surveys of AM fungi associated with endemic island plants are particularly rare. In the present investigation a molecular survey of AM fungi associated with the island plant genus Tolpis (Asteraceae) was performed. We characterized the molecular diversity of AM fungal symbionts associated with Tolpis on three islands of the Canarian archipelago using two nuclear DNA markers. Particular focus is placed on stringent quality filtering of fungal DNA sequences, the generation of operational taxonomic units, and their taxonomic assignment via similarity searches against DNA sequence databases. We found numerous putatively novel fungal genotypes in the Canary Islands, particularly among the non-endemic plant hosts. Careful database selection for taxonomic assignment is found critical for a reliable characterization of AM fungal genotypes.