"Exploring bacteria-phage interactions and coevolution in the phyllosphere"

A brief summary of Steven’s research:
 

“Drought can reduce microbial activity and nutrient cycling inecosystems that are vulnerable to increasing drought frequency and intensity. However, we lack a detailed understanding of the drought stress adaptations of environmental microbes. Our research team hypothesized that drought causes greater microbial allocation to survival relative to growth pathways. Using metatranscriptomic and metabolomic data, we analyzedthe physiological responses of surface soil microbial communities to long-term drought in Californian grassland and shrubland ecosystems. In grassland, microbial communities from 10-year drought treatments had distinct functional profileswith greater investment in production or uptake of compatible solutes like trehalose and ectoine as well as inorganic ions to maintain cellular osmotic balance. These communities also increased expression of genes underlying capsular and extracellular polymeric substances possibly as a mechanism to retain water. Overall, grass litter communities respond to drought with greater allocation to survival traits relative to growth traits. In contrast, communities on more chemicallycomplex shrub litter had smaller physiological responses to long-term drought but higher investment in resource acquisition traits, suggesting that the functional response to drought is constrained by substrate quality. Our findings suggest, for the first time in a field setting, trade-offs between microbial drought stress tolerance, resource acquisition, and growth traits in leaf litter microbial communities. These trade-offs likely affect rates of biogeochemical cycling in surface soils.”