title: BcAtf1, a global regulator, controls various differentiation processes and phytotoxin production in Botrytis cinerea.
abstract: Atf1-homologous basic region leucine zipper (bZIP) transcription factors are known to act downstream of the stress-activated mitogen-activated protein kinase (SAPK) cascade in mammals, as well as in several fungi; they regulate the transcription of genes involved in the general stress response. Functional analyses of BcAtf1 in Botrytis cinerea show that it is also connected to the SAPK BcSak1, as it shares several stress response target genes. However, Δbcatf1 mutants are not hypersensitive to osmotic or oxidative stress, as are Δbcsak1 mutants. Both BcSak1 and BcAtf1 are regulators of differentiation, but their roles in these processes are almost inverse as, in contrast with Δbcsak1, Δbcatf1 mutants are significantly impaired in conidia production and do not differentiate any sclerotia. They show extremely vigorous growth in axenic culture, with a thick layer of aerial hyphae and a marked increase in colonization efficiency on different host plants and tissues. In addition, the sensitivity to cell wall-interfering agents is increased strongly. Microarray analyses demonstrate that the loss of BcAtf1 leads to extensive transcriptional changes: apart from stress response genes, the expression of a broad set of genes, probably involved in primary metabolism, cell wall synthesis and development, is affected by BcAtf1. Unexpectedly, BcAtf1 also controls secondary metabolism: the mutant contains significantly elevated levels of phytotoxins. These data indicate that BcAtf1 controls a diversity of cellular processes and has broad regulatory functions.
authors.affiliation: Institut für Biologie und Biotechnologie der Pflanzen, Westf. Wilhelms-Universität, Hindenburgplatz 55, D-48143 Münster, Germany.
authors.forename: Nora
authors.initials: N
authors.lastname: Temme
authors.forename: Birgitt
authors.initials: B
authors.lastname: Oeser
authors.forename: Michelli
authors.initials: M
authors.lastname: Massaroli
authors.forename: Jens
authors.initials: J
authors.lastname: Heller
authors.forename: Adeline
authors.initials: A
authors.lastname: Simon
authors.forename: Isidro González
authors.initials: IG
authors.lastname: Collado
authors.forename: Muriel
authors.initials: M
authors.lastname: Viaud
authors.forename: Paul
authors.initials: P
authors.lastname: Tudzynski
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects / Q000235:genetics; D000595:Amino Acid Sequence; D020171:Botrytis / Q000166:cytology* / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism*; D007887:Fabaceae / Q000187:drug effects / Q000382:microbiology; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D020869:Gene Expression Profiling; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects; D005800:Genes, Fungal / Q000235:genetics; D006861:Hydrogen Peroxide / Q000494:pharmacology; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D008954:Models, Biological; D008969:Molecular Sequence Data; D009183:Mycotoxins / Q000096:biosynthesis*; D010641:Phenotype; D016415:Sequence Alignment; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics
chemical_list: D005656:Fungal Proteins; D009183:Mycotoxins; D006861:Hydrogen Peroxide; D020929:Mitogen-Activated Protein Kinase Kinases