Project description:Quorum sensing (QS) enhances bacterial pathogenesis. How plants perceive QS signals remains elusive. Here, we report that Arabidopsis thaliana perceives 2'-aminoacetophenone (2’-AA), a QS-regulated volatile compound emitted from Pseudomonas aeruginosa, through cell-surface pattern recognition receptor (PRR) complexes that require BRASSINOSTEROID INSENSITIVE 1-ASSOCIATED KINASE (BAK1). 2’-AA activates PRR-mediated immunity and enhances plant resistance to Pseudomonas pathogens. The 2’-AA-activated immunity displayed structural specificity of the elicitor and genetic specificity of the PRR complexes. 2’-AA induces in vivo protein interactions between BAK1 and its co-functioning PPRs, meanwhile the plant transcriptome responded to 2’-AA similarly as to flg22, a bacterial immunogenic elicitor that activates BAK1-dependent immunity. Hence bacterial QS signals can be sensed by plant cell-surface immune receptors.
Project description:Infection-related development of phytopathogenic fungi is initiated by sensing and responding to plant surface cues. This response results in the formation of specialized infection structures, so-called appressoria. To unravel the program inducing appressoria in the biotrophic smut fungus Ustilago maydis, we exposed cells to a hydrophobic surface and the cutin monomer 16-hydroxy hexadecanoic acid. Genome-wide transcriptional profiling under these appressorium-inducing in vitro conditions revealed dramatic transcriptional changes in almost 20% of the genes. Comparisons with the U. maydis sho1 msb2 double mutant, lacking two putative sensors for plant surface cues, revealed that these plasma membrane receptors regulate a small subset of the surface cue-induced genes. These genes comprised mainly secreted proteins including plant cell wall degrading enzymes that facilitate plant penetration and secreted effectors that are essential virulence factors, with functions after penetration. Our data also demonstrate specific effects on two transcription factors that redirect the transcriptional regulatory network towards appressorium formation and plant penetration. Thus, plant surface cues prime U. maydis for biotrophic development.
Project description:Bacterial quorum sensing (QS) during pathogenesis is an indicator of increasing danger. How sessile plants perceive QS for defense is unclear. Here, we show that Arabidopsis thaliana perceives 2'-aminoacetophenone (2’-AA), a volatile QS signal from Pseudomonas aeruginosa, through cell surface pattern recognition receptor (PRR) complexes, resulting in multistrategic defense and disease resistance. The 2’-AA-induced plant immunity requires chemical and genetic specificity. 2’-AA binds to the cytoplasmic domain of BRI1-ASSOCIATED RECEPTOR KINASE1 (BAK1) and induces the formation of PRR complexes that initiate the plant immune responses. 2’-AA stimulates plant exudation of acetic acid, a volatile compound that effectively quenches QS and inhibits P. aeruginosa virulence. Plants exposed to 2’-AA reshaped the root microbiome by suppressing the abundant Pseudomonad taxa with increased bacterial diversity. These results illustrate the ability of plants to perceive and respond to pathogen QS.
Project description:Infection-related development of phytopathogenic fungi is initiated by sensing and responding to plant surface cues. This response results in the formation of specialized infection structures, so-called appressoria. To unravel the program inducing appressoria in the biotrophic smut fungus Ustilago maydis, we exposed cells to a hydrophobic surface and the cutin monomer 16-hydroxy hexadecanoic acid. Genome-wide transcriptional profiling under these appressorium-inducing in vitro conditions revealed dramatic transcriptional changes in almost 20% of the genes. Comparisons with the U. maydis sho1 msb2 double mutant, lacking two putative sensors for plant surface cues, revealed that these plasma membrane receptors regulate a small subset of the surface cue-induced genes. These genes comprised mainly secreted proteins including plant cell wall degrading enzymes that facilitate plant penetration and secreted effectors that are essential virulence factors, with functions after penetration. Our data also demonstrate specific effects on two transcription factors that redirect the transcriptional regulatory network towards appressorium formation and plant penetration. Thus, plant surface cues prime U. maydis for biotrophic development. Solopathogenic Ustilago maydis strain AM1 and its derivate AM1Δsho1Δmsb2 were grown to mid-log phase in YEPSL medium and resuspended in 2% YEPSL plus/minus 16-hydroxy hexadecanoic acid (HDA). The cell suspensions were sprayed on hydrophobic surface (Parafilm) and incubated for 12 h. As control, cells were sprayed on hydrophilic glass surface and incubated for 2 h. After RNA extraction Affymetrix microarrays were performed.
Project description:We sequenced the complete genome of an ectophytic fungus, Ramichloridium luteum, which colonizes the surface of apple fruit, and carried out comparative genomic and transcriptome analysis
Project description:RNA sequencing was applied to compare the transcriptome profiles of mycelium on potato dextrose for 15days (PDA15d) and mycelium on apple surface for 15days (DT15d).
