Bacterial and fungal communities in the hyphosphere soil of Dematophora necatrix cultured on supporting substrates of sea sand and twigs

To investigate the microbes involved in the synergistic decline phenomenon of the white root rot fungus Dematophora necatrix (synonym Rosellinia necatrix, strain W562) under non-lethal conditions at a lethal temperature in hot water treatment, amplicon sequencing of the bacterial 16S rRNA gene V3-V4 regions and fungal ITS2 regions was conducted. The experiment used a model system in which D. necatrix growing on supporting substrates of sea sand and twigs, or the substrates alone, were embedded in sieved unmanaged green field soil and then heated with a 44-h programmed setting (40 °C for 1 h, 35 °C or above for 7 h), mimicking the transition of field soil temperature by hot water treatment. Soils in close contact with hyphae or substrates, as well as bulk soil away from them, were sampled immediately after the treatment and after a one-week post-incubation at 22-24 °C. The control was incubated at 22-24 °C.