How do ectomycorrhizal fungi and soil enzymes respond to altitude in Nothofagus pumilio forest?.

MORETTO A, ; SMITH M; TRUONG C, ; MUJIC A, ; GABBARINI L, ; ESCOBAR J

Punta Arenas

Congreso; VIII Southern Connection Congress; 2016

Climate change strongly affects the biosphere,including soil microorganisms. In Southern temperate forests, Nothofagus trees are associated with a diverse community ofectomycorrhizal fungi that connect them in the soil through a ?web of fungi?.These mutualistic root symbionts favor tree growth and survival onnutrient-poor soil by facilitating the degradation of organic matter and themobilization of essential nutrients to the plant. In Tierra del Fuego, Nothofagus pumilio formscontinuous forests from almost sea level to treeline (ca. 150?700 m elevation)without interference from any other ectomycorrhizal tree species. The presenceof a single ectomycorrhizal tree along an altitudinal gradient is not foundanywhere else in the world and represents a unique opportunity to study theeffects of temperature on soil microorganisms. We collected 180 soil samplesalong 6 altitudinal gradients in Nothofagus pumilio forest and identified fungi communities by ITS1metagenomic barcoding via the Illumina platform. At each sampling point, we recordedsoil properties and measured by spectrophotometry the activity of fungalenzymes involved in carbohydrate degradation (CAZymes) and nutrientmobilization (acid phosphatases). Ectomycorrhizal fungi,mainly from the class Agaricomycetes,dominated the soil community and were most diverse at middle altitude (ca. 400 m) following a mid-domaineffect. Shifts in fungal communities occurred along altitudinal gradients,associated with changes in the activity of fungal enzymes and soil nutrientsfactors. These results provide unprecedented resolution of ecological functionsof soil fungi across altitudinal gradients and may predict how climate changewill impact these forest ecosystems.