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Dissociation of immune responses from pathogen colonization supports pattern recognition in C. elegans.

ABSTRACT: Caenorhabditis elegans has been used for over a decade to characterize signaling cascades controlling innate immune responses. However, what initiates these responses in the worm has remained elusive. To gain a better understanding of the initiating events we delineated genome-wide immune responses to the bacterial pathogen Pseudomonas aeruginosa in worms heavily-colonized by the pathogen versus worms visibly not colonized. We found that infection responses in both groups were identical, suggesting that immune responses were not correlated with colonization and its associated damage. Quantitative RT-PCR measurements further showed that pathogen secreted factors were not able to induce an immune response, but exposure to a non-pathogenic Pseudomonas species was. These findings raise the possibility that the C.elegans immune response is initiated by recognition of microbe-associated molecular patterns. In the absence of orthologs of known pattern recognition receptors, C. elegans may rely on novel mechanisms, thus holding the potential to advance our understanding of evolutionarily conserved strategies for pathogen recognition.

SUBMITTER: Twumasi-Boateng K

PROVIDER: S-EPMC3325959 | biostudies-literature |

REPOSITORIES: biostudies-literature

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The Arabidopsis miR396 mediates pathogen-associated molecular pattern-triggered immune responses against fungal pathogens

Project description:A first line of defense against pathogen infections is the recognition of pathogen-associated molecular patterns (PAMPs), leading to PAMP-triggered immunity (PTI). MicroRNAs (miRNAs) are primarily known as central regulators of plant development, but a few have also been connected to immunity. We have found that several fungal pathogens lead to a reduction in miR396 levels, suggesting that miR396 are negative regulators of downstream defense responses. In agreement with such as scenario, constitutive attenuation of miR396 activity enhances resistance to infection by fungal pathogens, while increased miR396 activity reduces pathogen resistance. We conclude that constitutive reduction of miR396 levels confer a primed state for enhanced defense reactions

2017-02-28 | GSE76819 | GEO

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