BayCEER Workshop 2019

Drought stress memory in filamentous soil fungi

O 1.4 in Plant and soil responses to drought: Interdisciplinary approaches and views

10.10.2019, 12:00-12:15, H36, NW III

Drought is a common stressor for soil organisms. One adaptive mechanism is “stress priming”, the ability to cope with a severe stress (“triggering”) by retaining a memory from a previous mild stress event (“priming”). While plants have been extensively investigated for drought memory, only scare information is available for filamentous soil fungi and its implications for soil microbial communities. We investigated the potential for drought-induced stress priming on single species as well its effect on microbial communities in forest A-horizons. Batch experiments with 4 treatments were conducted: exposure to priming and/or triggering as well as non-stressed controls. A priming stress was caused by desiccation to pF 4. The samples were then rewetted and after up to 14 days of recovery triggered (pF 6). After triggering, microbial biomass and activity as well as microbial communities by 16S and ITS rDNA sequencing were analysed.

Especially receptive to stress priming seem to be species within the fungal classes Mortierellomycetes, Pezizomycetes, and Tremellomycetes. Shifts in microbial community compositions could be observed in response to stress priming in some cases. In general, the nature of the response depends on the original composition of the microbial community and the occurrence of a subsequent triggering event. Species investing high amounts of resources into the primed state likely prevail if a triggering occurs (especially noteworthy was Byssonectria fusispora). If no triggering occurs, species investing lower amounts potentially like Mortierella sp. seem to prevail.

Some filamentous fungi show the potential for drought-induced stress priming leading to advantages under severe stress events. Yet, the effect seems to be species specific with potentially high impact on composition and activity of microbial communities considering the expected increase of drought events.

 

 

Keywords: Drought stress; Filamentous fungi; Metagenome sequencing; Microbial communities; Stress memory; Stress priming

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