How do ectomycorrhizal fungi and soil enzymes respond to altitude in Nothofaguspumilio forest

MORETTO, ALICIA; GABBARINI , LUCIANO; ESCOBAR, JULIO; TRUONG, CAMILLE; MUJIC, ALIJA

Congreso; VIII SOUTHERN CONNECTION CONGRESS; 2016

Climate change strongly affects the biosphere, including soil microorganisms. In Southern temperateforests, Nothofagus trees are associated with a diverse community of ectomycorrhizal fungi that connectthem in the soil through a ?web of fungi?. These mutualistic root symbionts favor tree growth and survivalon nutrient-poor soil by facilitating the degradation of organic matter and the mobilization of essentialnutrients to the plant. In Tierra del Fuego, Nothofagus pumilio forms continuous forests from almost sealevel to treeline (ca. 150?700 m elevation) without interference from any other ectomycorrhizal tree species.The presence of a single ectomycorrhizal tree along an altitudinal gradient is not found anywhere else inthe world and represents a unique opportunity to study the effects of temperature on soil microorganisms.We collected 180 soil samples along 6 altitudinal gradients in Nothofagus pumilio forest and identifiedfungi communities by ITS1 metagenomic barcoding via the Illumina platform. At each sampling point, werecorded soil properties and measured by spectrophotometry the activity of fungal enzymes involved incarbohydrate degradation (CAZymes) and nutrient mobilization (acid phosphatases). Ectomycorrhizal fungi,mainly from the class Agaricomycetes, dominated the soil community and were most diverse at middlealtitude (ca. 400 m) following a mid-domain effect. Shifts in fungal communities occurred along altitudinalgradients, associated with changes in the activity of fungal enzymes and soil nutrients factors. Theseresults provide unprecedented resolution of ecological functions of soil fungi across altitudinal gradients andmay predict how climate change will impact these forest ecosystems.