Bacillus subtilis and Pseudomonas fluorescens Trigger Common and Distinct Systemic Immune Responses in Arabidopsis thaliana Depending on the Pathogen Lifestyle.
Ngoc Huu NguyenPatricia Trotel-AzizSandra VillaumeFanja RabenoelinaAdrian SchwarzenbergEric Nguema-OnaChristophe ClémentFabienne BaillieulAziz AzizPublished in: Vaccines (2020)
Plants harbor various beneficial bacteria that modulate their innate immunity, resulting in induced systemic resistance (ISR) against various pathogens. However, the immune mechanisms underlying ISR triggered by Bacillus spp. and Pseudomonas spp. against pathogens with different lifestyles are not yet clearly elucidated. Here, we show that root drenching of Arabidopsis plants with Pseudomonas fluorescensPTA-CT2 and Bacillus subtilis PTA-271 can induce ISR against the necrotrophic fungus B. cinerea and the hemibiotrophic bacterium Pseudomonas syringae Pst DC3000. In the absence of pathogen infection, both beneficial bacteria do not induce any consistent change in systemic immune responses. However, ISR relies on priming faster and robust expression of marker genes for the salicylic acid (SA), jasmonic acid (JA), and ethylene (ET) signaling pathways upon pathogen challenge. These responses are also associated with increased levels of SA, JA, and abscisic acid (ABA) in the leaves of bacterized plants after infection. The functional study also points at priming of the JA/ET and NPR1-dependent defenses as prioritized immune pathways in ISR induced by both beneficial bacteria against B. cinerea. However, B. subtilis-triggered ISR against Pst DC3000 is dependent on SA, JA/ET, and NPR1 pathways, whereas P. fluorescens-induced ISR requires JA/ET and NPR1 signaling pathways. The use of ABA-insensitive mutants also pointed out the crucial role of ABA signaling, but not ABA concentration, along with JA/ET signaling in primed systemic immunity by beneficial bacteria against Pst DC3000, but not against B. cinerea. These results clearly indicate that ISR is linked to priming plants for enhanced common and distinct immune pathways depending on the beneficial strain and the pathogen lifestyle.
Keyphrases
- arabidopsis thaliana
- bacillus subtilis
- transcription factor
- immune response
- dendritic cells
- candida albicans
- signaling pathway
- biofilm formation
- drug induced
- metabolic syndrome
- high glucose
- cardiovascular disease
- plant growth
- poor prognosis
- physical activity
- diabetic rats
- computed tomography
- magnetic resonance
- magnetic resonance imaging
- toll like receptor
- staphylococcus aureus
- epithelial mesenchymal transition
- cell proliferation
- gene expression
- pi k akt
- dna methylation
- multidrug resistant