Bacterial and fungal communities in the hyphosphere soil of Dematophora necatrix cultured on supporting substrates of twigs and cellulose acetate filters

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 twigs and cellulose acetate filters were embedded in sieved unmanaged green field soil and then heated with a 44-h programmed setting, mimicking the transition of field soil temperature by the hot water treatment. Soils in close contact with hyphae, as well as the bulk soil away from them, were sampled immediately after the treatment and after a one-week post-incubation. Experimental conditions: twigs experiment (treatment) 38 °C for 1 h, 35 °C or above for 3 h, (control) 22-24 °C, (post-incubation) 20-25 °C; filters experiment (treatment) 39 °C for 1 h, 35 °C or above for 7 h, (control) 25 °C, (post-incubation) 24-25 °C.