Fungal diversity and colonization in roots seed trees of Swietenia macrophylla King (Magnoliophyta: Meliaceae) in the tropical rainforest of Laguna Om, Quintana Roo, Mexico

Aim of study: (i) To investigate the diversity of arbuscular mycorrhizal fungi (AMF) associated with the roots of seed trees stands in a conserved and natural population of mahogany (Swietenia macrophylla), based on rDNA sequences; and (ii) to evaluate the dual colonization by AMF and dark septate fungi (DSF), showing the types of fungal colonization patterns in the dry season. Area of study: Tropical rainforest of Ejido Laguna Om, Quintana Roo, Mexico. Materials and methods: We evaluated the AMF and DSF colonization in secondary root segments of ten adult trees of mahogany. We analysed the diversity of AMF in one composite sample of mahogany roots (three trees) using 18S rDNA gene with Illumina MiSeq platform. Main results: Through metabarcoding 14 virtual taxa belonging mainly to the genus Glomus and Diversispora were obtained, VTX00186 being the most abundant. The percentages of colonization for the different fungal structures were hyphae 80%, vesicles 18%, coils 2%, and arbuscules 0.5%; for DSF, 60% hyphae and 12% microsclerotia. The Paris-type colonization predominated with 61% in the roots. Research highlights: The knowledge of the AMF diversity present in natural mahogany forests will allow the selection of species for inoculation management seeking to enhance seedling survival and growth of this species.