title: The transcriptional response to nonself in the fungus Podospora anserina.
abstract: In fungi, heterokaryon incompatibility is a nonself recognition process occurring when filaments of different isolates of the same species fuse. Compatibility is controlled by so-called het loci and fusion of strains of unlike het genotype triggers a complex incompatibility reaction that leads to the death of the fusion cell. Herein, we analyze the transcriptional changes during the incompatibility reaction in Podospora anserina. The incompatibility response was found to be associated with a massive transcriptional reprogramming: 2231 genes were up-regulated by a factor 2 or more during incompatibility. In turn, 2441 genes were down-regulated. HET, NACHT, and HeLo domains previously found to be involved in the control of heterokaryon incompatibility were enriched in the up-regulated gene set. In addition, incompatibility was characterized by an up-regulation of proteolytic and other hydrolytic activities, of secondary metabolism clusters and toxins and effector-like proteins. The up-regulated set was found to be enriched for proteins lacking orthologs in other species and chromosomal distribution of the up-regulated genes was uneven with up-regulated genes residing preferentially in genomic islands and on chromosomes IV and V. There was a significant overlap between regulated genes during incompatibility in P. anserina and Neurospora crassa, indicating similarities in the incompatibility responses in these two species. Globally, this study illustrates that the expression changes occurring during cell fusion incompatibility in P. anserina are in several aspects reminiscent of those described in host-pathogen or symbiotic interactions in other fungal species.
authors.affiliation: Université de Paris Sud, Institut de Génétique et Microbiologie, UMR8621 Orsay, France.
authors.forename: Frédérique
authors.initials: F
authors.lastname: Bidard
authors.forename: Corinne
authors.initials: C
authors.lastname: Clavé
authors.forename: Sven J
authors.initials: SJ
authors.lastname: Saupe
mesh_terms: D015825:Chromosomes, Fungal / Q000235:genetics; D016000:Cluster Analysis; D015536:Down-Regulation / Q000187:drug effects / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D020869:Gene Expression Profiling; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects; D005800:Genes, Fungal / Q000235:genetics; D007700:Kinetics; D058977:Molecular Sequence Annotation; D009183:Mycotoxins / Q000633:toxicity; D009492:Neurospora crassa / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D048468:Podospora / Q000187:drug effects / Q000235:genetics* / Q000502:physiology*; D014158:Transcription, Genetic / Q000187:drug effects; D015854:Up-Regulation / Q000187:drug effects / Q000235:genetics
chemical_list: D005656:Fungal Proteins; D009183:Mycotoxins
keywords: HET domain; Podospora anserina; STAND proteins; heterokaryon incompatibility; nonself recognition