Volatile-mediated antagonism of soil bacterial communities against fungi

Summary

It is increasingly recognized that volatile organic compounds (VOCs) may play an important role in belowground competition between fungi and bacteria. However, evidence for the actual importance of such VOC-mediated antagonistic interactions within soil microbial communities is lacking. Here, we examined colonization of sterile agricultural soils by fungi and bacteria from non-sterile soil inoculums during exposure to VOCs emitted by soil-derived bacterial communities. Soil colonisation by fungi was negatively affected by exposure to VOCs emitted by bacterial community whereas that of bacteria was barely affected. Furthermore, there were strong effects of bacterial community VOCs on the assembly of the soil colonizing fungal communities. We argue that our results point at a collective VOCs-mediated antagonism of soil bacteria against fungi. Given the better exploration abilities of filamentous fungi in soils, a bacterial VOCs war on fungi may help bacteria to defend occupied nutrient patches against invading fungi.