Core microbes in <i>Cordyceps militaris</i> sclerotia and their nitrogen metabolism-related ecological functions

The model <i>Cordyceps</i> species <i>Cordyceps militaris</i> is rich in therapeutic compounds. It has recently been demonstrated that symbiotic microbes in sclerotia affect <i>Cordyceps'</i> growth, development, and secondary metabolite production. In this study, core microbes were identified based on <i>C. militaris</i> sclerotia samples obtained from the same site over 5 years. Additionally, bacterial strains isolated from <i>C. militaris</i> sclerotia were found to affect metabolite production and nitrogen utilization, based on functional tests. Moreover, based on the bacterial nitrogen metabolism capacity in the sclerotia and its influence on <i>C. militaris</i> metabolite production, we deduced that bacteria in the sclerotia can indirectly affect <i>C. militaris</i> metabolite production by regulating nitrogen metabolism. This is the first report on how bacteria in the sclerotia affect <i>C. militaris</i> metabolite production from the perspective of the nitrogen cycle. The results increase our understanding of microbial functions in <i>C. militaris</i> sclerotia.