Mycorrhizal mutualists and potential feedback effect on host plants under drought

Background

Climate change causes more frequent and severe drought events. Ectomycorrhizal (ECM) fungi are an important biotic factor in the survival of forest trees under such stressful conditions. Studies on the impact of mutualistic fungi on drought resistance of trees provide conflicting evidence.

Research questions and hypothesis

This PhD-thesis aims at elucidating the effect of drought and forest fires on ECM communities of mountain forests. We are also interested whether plant genetics has an influence on the response of ECM to drought stress. We hypothesize that drought and forest fires significantly influence ECM species composition and diversity. This Dissertation project is tightly linked to Dissertation Projects 1-1, 1-2, 1-5). The same sites / tree saplings will be used in order to allow for a meaningful collaboration and interconnection of research topics – methods – and results.

Approach and methods

Different methodological approaches will be used: in situ detection (see Dissertation Projects 1-2, 1-5), bioassays, common garden experiments (see Dissertation Project 1-1). ECM communities are quantified and detected based rDNA ITS sequencing. Soil bioassays will elucidate patterns of ECM availability and establishment under drought. A common garden experiment is planned in a natural field setting using 3-4 years old seedlings with different genetics (drought tolerant / intolerant). Drought stress is simulated by rain shelters. Plant health, survival rates and productivity are assessed after two years, and related to ECM community dynamics and soil microbial biomass production.

Time frame