Synergies between Heat Disturbance and Inoculum Size Promote the Invasion Potential of a Bacterial Pathogen in Soil

Inoculum size contributes to the invasion potential of pathogens in the soil. However, the role of inoculum size in determining the fate of pathogens in disturbed soils remains unclear. Herein, we investigated the survival rates of a bacterial pathogen, Ralstonia solanacearum, in soils subjected to heat as a simulated disturbance. Our results revealed that heating increased soil resource availability but reduced resource differentiation between R. solanacearum and indigenous bacterial communities. In both non-heated and heated soils, invader abundances increased with inoculum size, with a greater magnitude in heated soils. Inoculum size and heat-induced increases in soil-available carbon and nitrogen best predicted invasion success. Altogether, our findings suggested that the invasion by soil pathogens could be predicted by synergies between heat perturbation and inoculum size.

Automated summary

Inoculum size and heat perturbations have synergistic effects on predicting the invasion success of soil pathogens. Heating increases soil resource availability, but reduces resource differentiation between the pathogen and indigenous bacteria. The abundance of the pathogen increases with inoculum size in both heated and non-heated soils, with a greater effect in heated soils. Inoculum size and the increase in available carbon and nitrogen in the soil best predict invasion success.