Potential antimicrobial properties of the cyanobacterium Microcoleus vaginatus in relationship to the moss Bryum argenteum

Biological soil crusts play important ecological roles in arid desert regions. These crusts cycle nutrients, prevent wind/water erosion, and form the basis of food chains and soil formation in desert communities. Primary components of these structures include two desert moss species Bryum argenteum and Syntrichia caninervis, and Microcoleus vaginatus, a cyanobacterium. Our Phase I experiment strongly suggests that in an environment of intense light, a condition of stress to Syntrichia caninervis, there is an increase in shoot regeneration when cyanobacteria are present compared to when they are absent. Microcoleus is a highly motile species and our lab observations of fewer deleterious bacteria, algae, and fungi in cultures containing the cyanobacterium led us to hypothesize that the cyanobacterium may be deterring the development of bacteria/algae/fungi that can slow moss growth. The current experiment seeks to determine whether a benefit of Microcoleus to the mosses lies in its antimicrobial activity. Two microbial candidates (a fungus and a bacterium) were selected from early lab cultures and determined to impede the growth of these moss species. These microbes were then cultured individually and in combination with the moss only, with the cyanobacterium only, and with both moss and cyanobacterium together. Each treatment was allowed to incubate under simulated natural conditions of light and moisture for a period of eight weeks. Final results will be determined through biomass weights and area measurements