Rhizobacteria-mediated induced systemic resistance (ISR) in Arabidopsis: involvement of jasmonate and ethylene

The capacity of a plant to express a broad-spectrum systemic acquired \nresistance (SAR) after primary infection is well known and extensively \nstudied. A relatively unknown form of induced disease \nresistance is triggered by nonpathogenic, root-colonizing rhizobacteria and is \ncommonly referred to as rhizobacteria-mediated \ninduced systemic resistance (ISR). Rhizosphere bacteria are present in large \nnumbers on the root. Certain strains stimulate \nplant growth and are therefore called plant \ngrowth-promoting rhizobacteria (PGPR). Selected \nstrains with biological control activity, mainly \nfluorescent Pseudomonas spp., reduce plant \ndiseases by suppressing soil-borne pathogens \nthrough competition for nutrients, siderophore-mediated \ncompetition for iron or antibiosis.