P-118 - Harnessing the potential of pathogen suppressive microbiome through plant interspecific interaction

Certain plant-associated symbiotic microbes can suppress plant pathogens. Previously we found that interspecific plant interaction with onion (Allium cepa) shapes the tomato disease suppressive microbiome. Here, using next-generation sequencing techniques, we sought to unravel the role of plant interspecific interaction-altered tomato microbiome in plant growth and fitness. First, we confirmed that coculture with different onion cultivars alters tomato rhizosphere bacterial community. Then, in the next trial, we found that tomato inoculated with Fusarium oxysporum f. sp. lycopersici – the pathogen, showed reduced disease incidence and biomass loss when cocultured with onion as compared to monoculture. The 16S rRNA amplicon and shotgun metagenome sequencing revealed that tomato with or without onion, and with or without pathogen, shaped the bacterial taxonomic and functional community differently. Besides the positive results in several in vitro assays, all bacteria belonging to the Pseudomonas isolated from tomato rhizosphere were able to suppress pathogen growth in vitro and disease incidence in sterilized and non-sterilized conditions in pot experiments. Finally, inoculation of tomato with GFP-labeled Pseudomonas sp. P829 using a split root system showed that the presence of onion stimulated tomato to recruit beneficial bacteria. This study revealed the potential of plant-interspecific interactions in harnessing plant-microbe interaction for suppressing diseases.