Oligotrophic supply intensity shapes cultivation-induced restructuring of bacterial communities in desert soils

Desert soils are extremely poor in nutrients, and most microorganisms living in these environments must cope with long-term resource limitation. In this study, we investigated how different levels of nutrient supply influence which soil bacteria can be cultivated from the Taklimakan Desert. By using a gradient of cultivation conditions ranging from standard low-nutrient medium to highly diluted medium and sterile water, we compared the resulting microbial communities with those originally present in desert soils.We found that laboratory cultivation strongly reshaped microbial community composition, but reducing nutrient supply further influenced which bacterial groups became enriched. Lower nutrient conditions favored certain bacteria that are commonly reported from nutrient-poor environments, while bacteria that grow well under higher nutrient availability were more abundant on standard media. In addition, microbial communities cultivated under stronger nutrient limitation showed simpler patterns of co-occurrence.Overall, our results show that nutrient supply level is an important factor that influences cultivation outcomes in desert soil microbiology. Using nutrient gradients rather than a single culture condition can improve access to bacterial diversity adapted to oligotrophic environments and help bridge the gap between cultivation-based and molecular studies of desert soil microbes.