NSF Postdoctoral Fellowship in Biology: Symbiosis as a Means of Survival for Biological Soil Crust Microbes

Fellow's name: Erin Carr Proposal number: 2209217 Research title: Symbiosis as a Means of Survival for Biological Soil Crust Microbes

Sponsoring scientist(s) and host institution(s): Steven Harris, Iowa State University; and Wayne Riekhof, University of Nebraska-Lincoln

This action funds an NSF Postdoctoral Research Fellowship in Biology for FY 2021, Integrative Research Investigating the Rules of Life Governing Interactions Between Genomes, Environment and Phenotypes. The fellowship supports research and training of the fellow that will contribute to the area of Rules of Life in innovative ways. This project aims at understanding how microbes growing in desert soils can use chemical interactions to obtain vital nutrients and withstand the extreme stress of desert ecosystems.

Microorganisms living in desert soils include bacteria, algae, fungi, and lichens. Most research attention has focused on photosynthetic bacteria and algae, as well as nitrogen-fixing bacteria. These microbes provide a source of nutrients such as carbon sugar and ammonia nitrogen, respectively, to the entire community.

However, the role of fungal species in these communities is still unknown. This work aims to increase understanding of desert microbial communities by determining the role of these fungal species, which is believed to include providing melanin for increased ultraviolet and stress resistance for the whole community. This research will help provide new knowledge that will make it possible to use these microbial communities to perform soil metal removal, increase agricultural soil nutrients, retain soil moisture in droughts, and prevent desertification of non-desert ecosystems.

Biological soil crusts (or soil crusts) are microbial communities that form biofilms on the surface of nutrient-deplete desert soils. It is hypothesized that the microbes residing in the soil crust engage in transient interactions akin to that of a lichen symbiosis, to obtain nutrients and survive extreme abiotic stress. To investigate this hypothesis, novel microbial species isolated from a soil crust will be used to: 1) show that non-lichenized melanized fungi can establish mutualistic interactions with bacteria and algae; 2) observe how fungal melanin affects microbes from the soil crust, to determine if melanin can be considered a “public good” for abiotic resistances and used as a carbon source; and 3) identify metabolites produced and gene regulation differences during multi-species cultures to determine how these microbes interact.

The fellow has additional goals to improve both representation and experience in undergraduate research by 1) recruiting undergraduate researchers from underrepresented groups and 2) developing a monthly basic lab techniques workshop to provide free lab experience to all undergraduates. Additional use of funds from this fellowship will be put towards increasing collaborations with fellow researchers in this field by developing a virtual conference.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.