Defined polyxenic cultivation of species of <i>Didymium</i> and <i>Physarum</i> for small-scale laboratory production of plasmodia, sclerotia, and sporocarps

originally collected from maize. Starting from spore-based cultures, we optimized feeding regimes using bacterial and yeast mixtures, introduced a purification method combining antibiotic agar and low-heat-killed yeast, and demonstrated long-term culture maintenance at low temperature. Growth dynamics were modeled via the area of microbial feed consumed, revealing strong species- and temperature-dependent differences. Controlled sclerotization yielded sclerotia with quantifiable macrocyst activity, assessed by phase-contrast microscopy of cytoplasmic movement as a reproducible proxy for macrocyst functionality. Sporulation was successfully induced for all four species, with interspecific variation in sporocarp formation and spore germination rates. Together, these methods enable full life cycle completion in the laboratory and provide standardized inoculum sources in small scale for downstream applications.