Abstract Detail

Stress-tolerant mosses: adaptations to life on the edge, from genes to ecosystems

Fisher, Kirsten [1].

Living with Moss: Environmental Extremes Structure Functional Traits in Biocrust Microbial Communities.

Biological soil crusts (biocrusts) are widespread in drylands and deserts. Depending on successional stage and prevailing environmental conditions, cyanobacteria, mosses, or lichens may constitute the dominant photoautotroph in biocrust communities. At the microhabitat scale, biocrusts also host hypolithic communities that live under semi-translucent quartz stones. In desert environments, both exposed and hypolithic niches experience extreme conditions such as high UV radiation, desiccation, and temperature fluctuations; however, hypolithic communities are somewhat protected from extremes relative to biocrust communities. Comparing moss- versus cyanobacteria-dominated biocrust and hypolith communities can answer outstanding questions regarding the influence of the dominant photoautotroph and adaptations to environmental extremes. Using metagenomic sequencing, we assessed the functional potential of bacterial dryland soil communities and identified the functional underpinnings of ecological niche differentiation in moss and cyanobacterial biocrusts versus hypoliths. Overall, the dominant photoautotroph had less of an impact on functional pathway differences than microhabitat niche (exposed biocrust versus hypolith). Genes and pathways differing in abundance between biocrusts and hypoliths indicate that biocrust bacterial communities adapt to the higher levels of UV radiation, desiccation, and temperature extremes through an increased ability to repair damaged DNA, sense and respond to environmental stimuli, and interact with other community members and the environment. Intracellular competition appears to be crucial to both communities, with biocrust communities waging war using the Type VI Secretion System (T6SS) and hypoliths favoring antibiotic synthesis. Our findings indicate that functional traits in dryland bacterial communities are driven by adaptations to extremes and we identify some parallel strategies in bacteria and mosses that likely enable survival in dryland ecosystems.

1 - California State University, Los Angeles, Biological Sciences, 5151 State University Dr, Los Angeles, CA, 90032, USA

Biological Soil Crust

Presentation Type: Colloquium Presentations
Number: C5006
Abstract ID:619
Candidate for Awards:None

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