부산대학교 도서관

Background and aims: The rhizosphere microbiome has been shown to contribute to nutrient acquisition, protection against biotic and abiotic stresses and, ultimately, to changes in the development and physiology of plants. Here, using a controlled natural selection approach, we followed the microbial dynamics in the soil of Arabidopsis thaliana plants infected with the foliar pathogen Pseudomonas syringae DC3000 (Pst). Methods: Plants were iteratively cultivated on a pasteurised soil inoculated with the soil microbial community of the previous iteration isolated from the rhizosphere of plants infected with Pst (pst-line) or not (mock-line). Modification of soil microbial communities was assessed through an amplicon-based metagenomic analysis targeting bacterial and fungal diversity. Plant fitness and transcript abundance of stress hormone related genes were also analysed. Results: At the tenth and eleventh iterations respectively, we observed a reduction in disease severity of 81% and 85% in pst-lines as compared to mock-lines. These changes were associated with (i) an early induction of defence mechanisms mediated by salicylic acid, in pst-line as compared to mock-line, shown by the decrease in transcript abundance of salicylic acid related genes, whereas jasmonic acid, ethylene or abscisic acid related genes remained unchanged and (ii) a shift in soil bacterial, and not in fungal, composition. Conclusions: Our study suggests that these changes in soil bacterial composition are mediated by plant-soil feedback in response to Pst and resulted in an activation of SA-related immune response in the plant. This supports the concept of applying plant-soil feedbacks to enhance soil suppressiveness against foliar pathogens. [ABSTRACT FROM AUTHOR]