Local PCN suppression

Local microbiome-based suppression of below-ground plant pathogens is rarely included in agricultural management practices, despite its potential value for the transition towards sustainable food production. Exploitation of this disease suppressive potential of agricultural soils is hindered by the complexity of this phenomenon that is assumed to result from the actions of a local conglomerate of microbial antagonists. Studying non-homogeneously distributed disease suppressiveness within single fields could be instrumental in pinpointing this phenomenon. In this study, we selected four apparently homogeneous potato fields that showed a patchy PCN distribution. Under controlled greenhouse conditions, we discovered that soil from patches where PCN was absent was generally more suppressive to PCN than soils were PCN was present and its biotic origin of suppression was corroborated by gamma-sterilization. Subsequent analysis of the potato rhizosphere microbial community revealed contrasts in community composition between suppressive and conducive patches, and we identified various fungal (e.g. Arthrobotrys elegans and Metacordyceps chlamydosporia) and bacterial (e.g. Pseudomonas fluorescens) nematode antagonists that were positively correlated with PCN suppressive patches. Moreover, these sets of antagonists associated with PCN suppression were field-specific, thereby emphasizing the complex and multi-faced nature of this phenomenon. Together, our findings highlight that the local heterogeneity of the soil microbiome can influence the local establishment of a phytopathogen within a field.