Not only priming: Soil microbiota may protect tomato from root pathogens.

An increasing number of studies have investigated soil microbial biodiversity. However, the mechanisms regulating plant responses to soil microbiota are largely unknown. A previous work tested the hypothesis that tomato plants grown on native soils with their complex microbiotas respond differently from tomato growing in a sterile substrate. Two soils, suppressive or conducive to Fusarium oxysporum f. sp. lycopersici (FOL), and two genotypes susceptible and resistant to the same pathogen were considered. The work highlighted that the two tested soil microbiotas, irrespectively of their taxonomic composition, elicit the PAMP-triggered Immunity Pathway, the first level of plant defence, as well as an increased lignin synthesis, leading to an active protection when FOL is present in the soil. Here, we tested the expression of a panel of genes involved in Effector-Triggered Immunity (ETI), demonstrating that soil microbiota, beside genotype, affects plant resistance to FOL also modulating this pathway.