30/03/2023 Sven SAUPE UMR5095, IBGC, CNRS & Université de Bordeaux
Non-self recognition in fungi, mechanisms and evolution
| In filamentous fungi, cell fusions between conspecifics occur spontaneously and lead to the formation of heterokaryons. Yet, in most cases, such fusions trigger an incompatibility reaction that corresponds to the regulated cell death of the fusion cell. Incompatibility is controlled by so-called het-genes and limits the transmission of mycovirures between strains. Therefore, the adaptive value of incompatibility is thought to be related to its function as a prophylactic anti-viral defense system. Het-genes have been isolated in a handfull of model species including Podospora anserina, our main working model. A number of studies have revealed some remarkable similarities between the defense pathways operating in fungi and those found in other phyla in particular in animal and plant immunity and bacterial antiphage systems. The receptors controlling non-self recognition and cell death execution thus show deep evolutionary conservation. We will outline some of these similarities in particular in the case of NLRs, amyloid signaling, gasdermines, HET/TIR domains and HeLo-cell death execution domains. We will propose that het-systems derive by exaptation from pathways with general functions in immune defense and control of biotic interaction. Our intention is to contribute to a comparative immunology to define the similarity and differences between immune pathways in plants, animals, bacteria and fungi. |
Publiée : 22/02/2023