An ERF transcription factor StPti5, a novel regulator of endophyte community maintenance in potato

We have recently identified an ethylene response factor, StPti5, as a susceptibility factor that negatively regulates immune response to diverse pathogens. Here, we investigated the processes involved in colonisation of potato with beneficial organisms. RNA-seq showed that at the time of Bacillus subtilis biofilm establishment, immune responses in interacting roots were attenuated, and complex transcriptional network was triggered, with ethylene signalling being a central module and StPti5 strongly induced. Interestingly, the response is intensified if plants are inoculated by two antagonistic B. subtilis strains. While StPti5 is not involved in the establishment of biofilm on roots, we show that bacterial abundance increases in shoots of StPti5-silenced plants. Remarkably, root colonization by the arbuscular mycorrhizal fungus Rhizophagus irregularis was also higher in the StPti5-silenced plants. StPti5 is involved both in suppressing defence against harmful and limiting colonisation with beneficial microbes. Such mechanistic understanding of plant–microbe interaction paves the way for sustainable crop management. Overall design: DAP-seq experiments