Background: The biological control agent Pseudomonas chlororaphis PA23 is capable of protecting Brassica napus (canola) from the necrotrophic fungus Sclerotinia sclerotiorum via direct antagonism. While we have elucidated bacterial genes and gene products responsible biocontrol, little is known about how the host plant responds to bacterial priming on the leaf surface, including global changes in gene activity in the presence and absence of S. sclerotiorum.
Results: Application of PA23 to the aerial surfaces of canola plants reduced the number of S. sclerotiorum lesion-forming petals by 91.1%. RNA sequencing of the host pathogen interface showed that pretreatment with PA23 reduced the number of genes upregulated in response to S. sclerotiorum by 16-fold. By itself, PA23 activated unique defense networks indicative of defense priming. Genes encoding MAMP-triggered immunity receptors detecting flagellin and peptidoglycan were downregulated in PA23 only-treated plants, consistent with post-stimulus desensitization. Downstream, we observed reactive oxygen species (ROS) production involving low levels of HO and overexpression of genes associated with glycerol-3-phosphate (G3P)-mediated systemic acquired resistance (SAR). Leaf chloroplasts exhibited increased thylakoid membrane structures and chlorophyll content, while lipid metabolic processes were upregulated.
Conclusion: In addition to directly antagonizing S. sclerotiorum, PA23 primes the plant defense response through induction of unique local and systemic defense networks. This study provides novel insight into the effects of biocontrol agents applied to the plant phyllosphere. Understanding these interactions will aid in the development of biocontrol systems as an alternative to chemical pesticides for protection of important crop systems.
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http://dx.doi.org/10.1186/s12864-017-3848-6 | DOI Listing |
J Glob Antimicrob Resist
January 2025
Department of Medicine, Division of Clinical Infectious Diseases, Showa University School of Medicine, Tokyo, Japan.
Objectives: In Pseudomonas aeruginosa isolates, emerging meropenem resistance beyond imipenem resistance has become a problem. In this study, we aimed to investigate the relationship between the in vivo acquisition of antimicrobial resistance in fluoroquinolone- and carbapenem-resistant P. aeruginosa clinical isolates, the underlying molecular mechanisms, and exposure to antimicrobial agents.
View Article and Find Full Text PDFMicrobiol Res
January 2025
ICAR-Indian Agricultural Research Institute, New Delhi, India. Electronic address:
Bacterial blight of pomegranate caused by Xanthomonas axonopodis pv. punicae poses significant challenges to sustainable cultivation, necessitating eco-friendly management strategies, and this study explores the role of the phylloplane microbiome in disease suppression through metabarcoding, traditional microbiology, and antibacterial screening of microbial candidates. Here, we mapped the phylloplane microbiome of pomegranate cultivar 'Bhagwa' during bacterial blight development using metabarcoding sequencing (2443,834 reads), traditional microbiological methods (nutrient-rich and minimal media), and scanning electron microscopy.
View Article and Find Full Text PDFAntimicrob Agents Chemother
January 2025
Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy.
A strain positive for the metallo-beta-lactamase gene and resistant to trimethoprim-sulfamethoxazole was unexpectedly isolated from a surveillance rectal swab. The characterization of the strain revealed carriage of a 91 kb integrative and conjugative element (ICE) harboring several resistance determinants [, , , , ∆, , and ], closely related with a group of -type ICEs widespread among and other pseudomonads. Results highlighted the possible spreading of similar elements to , mediating the acquisition of relevant resistances.
View Article and Find Full Text PDFLuminescence
January 2025
School of Chemical Engineering, Yeungnam University, Gyeongsan, Republic of Korea.
Crystal Violet (CV) is a vibrant and harmful dye known for its toxicity to aquatic life and potential carcinogenic effects on humans. This study explores the removal of CV through photocatalysis driven by visible light, as well as examining the antibacterial and antibiofilm characteristics of zinc oxide nanoparticles (ZnO NPs) synthesized from the aerial roots of Ficus benghalensis. Various characterization techniques were employed to confirm the optical properties, crystal lattices, and morphology of ZnO NPs.
View Article and Find Full Text PDFFront Antibiot
August 2024
The Medical School, University of Jordan, Amman, Jordan.
Objectives: To evaluate the antimicrobial susceptibilities of Gram-positive and Gram-negative isolates from patients in Jordan between 2010 and 2021, through the Antimicrobial Testing Leadership and Surveillance (ATLAS) programme.
Methods: Medical centres in Jordan collected bacterial isolates from hospitalised patients with defined infection sources between 2010 and 2021 (no isolates collected in 2014). Antimicrobial susceptibility was interpreted using CLSI standards.
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