Adaptive Strategies in soil Bradyrhizobium
Bradyrhizobium species are among the most widely studied microbes because of their crucial relevance to symbiotic nitrogen fixation. However, recent studies have demonstrated that Bradyrhizobium are abundant in soil microbial communities worldwide and many may not be nitrogen-fixing symbionts. In a Community Science Project awarded by the Joint Genome Institute, we are using comparative genomics, transcriptomics and metabolomics to investigate the strategies that contribute to the success of this abundant and ubiquitous soil microbe in a variety of environments.
Oligotrophic microbes – those microbes that thrive in conditions where the effective nutrient availability is low – are likely a major component of uncultivated microbial diversity. While conducting high-throughput culturing of microbes from aquatic samples is relatively straightforward, soil and sediments are among the most complex of all environmental samples, often containing thousands of uncultivated microbial taxa in a multidimensional mineral-organic matrix. Since opening our doors, we have developed the infrastructure to culture and work with ultraoligotrophic sediment and soil cultures with high throughput.
Physiology of Desiccation Tolerance in Actinobacteria
The lack of water is one of the largest environmental stresses in Arizona’s Sonoran Desert. We isolated hundreds of Actinobacteria from shallow subsurface soils that are abundant members of the arid soil microbiome. In a Community Science Project awarded by the Joint Genome Institute, we are developing several of these strains into model systems to study the effects of desiccation and rehydration on actinobacterial physiology. We are using a combination of genomics, transcriptomics, and metabolomics to gain a better understanding about actinobacterial adaptations to dry environments—information that can be used to understand how microbial communities will change in response to dryer conditions in the future.
Roles of obligate oligotrophic bacteria from arid unclaimed mine tailings sites
Microbes are crucial for plant establishment and soil health in arid and semiarid unclaimed mine tailings sites. Although we know such sites can be extremely low in organic carbon and other nutrients, we don’t really understand the role of oligotrophic microbes in these microbial communities. As part of this project, we are cultivating abundant oligotrophs from mine tailings and integrating the information derived from these cultures with ongoing molecular characterization of tailing microbial communities.
“One world, many cultures”
Growth of the Arizona Culture Collection (AZCC)
AZCC growth 2017 - present
Arizona Culture Collection
Every culture we isolate is cryopreserved for potential future use. Such culture collections will almost certainly have utility in a changing world. We call our collection the Arizona Culture Collection (AZCC for short). When browsing NCBI, strains we isolate and identify are appended with an AZCC strain number. These strains are availible upon request. When requesting, keep in mind that some isolates are difficult to culture so we reserve the right to limit the number of strains requested at once. Also, while we do our best to ensure viability after cryopreservation, not all strains ‘wake up’ after being frozen and we have limited amounts of each isolate.