Diversity of Arbuscular Mycorrhizal Fungi in Araucaria Araucana is Affected for Fire Events in the Andes and Coastal Mountains of Chile

Araucaria araucana exhibits a high dependence on association with arbuscular mycorrhizal fungi (AMF), which have been scarcely studied within the natural distribution of this emblematic species. Understanding the diversity of AMF in ecosystems where A. araucana is present is fundamental for establishing reintroduction programs for this species in environments severely affected by environmental stresses such as recent forest fires. This study aimed to determine the diversity of AMF species in the rhizosphere of A. araucana in its natural distribution in the Andes and coastal mountains of southern Chile. The study encompassed four areas: (i) Coastal Mountain Range in Nahuelbuta National Park (NP), and (ii) the Andes Mountain Range in Conguillío National Park (CP), Tolhuaca National Park (TP), and China Muerta National Reserve (CMR), with conserved (c) and fire-affected (f) sites in the latter two areas. We identified 17 Glomeromycota species, 14 identified at the species level and three at the genus level. Fire-affected sites exhibited a different AMF composition compared to conserved sites. The highest abundances were represented by the genus Acaulospora, predominant in CP and CMR-f. Scutellospora showed higher abundance in CMR-c, Entrophospora in TP-f, Funneliformis in TP-c, Glomus in NP, CP, and CMR-f, and Septoglomus in CMR-f, with representation ranging from 15 to 24.9% of total spore populations. This study provides the first characterization of AMF across a wide geographic area directly from the rhizosphere of A. araucana forests, identifying species with potential to be used in inoculation programs to improve the reestablishment of A. araucana in anthropogenically affected sites, especially those impacted by fire events.