title: ProA, a transcriptional regulator of fungal fruiting body development, regulates leaf hyphal network development in the Epichloë festucae-Lolium perenne symbiosis.
abstract: Transcription factors containing a Zn(II)2 Cys6 binuclear cluster DNA-binding domain are unique to fungi and are key regulators of fungal growth and development. The C6-Zn transcription factor, Pro1, in Sordaria macrospora is crucial for maturation of sexual fruiting bodies. In a forward genetic screen to identify Epichloë festucae symbiosis genes we identified a mutant with an insertion in proA. Plants infected with the proA mutant underwent premature senescence. Hyphae of ΔproA had a proliferative pattern of growth within the leaves of Lolium perenne. Targeted deletion of proA recapitulated this phenotype and introduction of a wild-type gene complemented the mutation. ΔproA was defective in hyphal fusion. qPCR analysis of E. festucae homologues of S. macrospora genes differentially expressed in Δpro1 identified esdC, encoding a glycogen-binding protein, as a target of ProA. Electrophoretic mobility shift assay analysis identified two binding sites for ProA in the intergenic region of esdC and a divergently transcribed gene, EF320. Both esdC and EF320 are highly expressed in a wild-type E. festucae-grass association but downregulated in a proA-mutant association. These results show that ProA is a key regulator of in planta specific growth of E. festucae, and therefore crucial for maintaining a mutualistic symbiotic interaction.
authors.affiliation: Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya, 464-8601, Japan; Institute of Fundamental Sciences, Massey University, Private Bag 11222, Palmerston North, 4442, New Zealand.
authors.forename: Aiko
authors.initials: A
authors.lastname: Tanaka
authors.forename: Gemma M
authors.initials: GM
authors.lastname: Cartwright
authors.forename: Sanjay
authors.initials: S
authors.lastname: Saikia
authors.forename: Yuka
authors.initials: Y
authors.lastname: Kayano
authors.forename: Daigo
authors.initials: D
authors.lastname: Takemoto
authors.forename: Masashi
authors.initials: M
authors.lastname: Kato
authors.forename: Takashi
authors.initials: T
authors.lastname: Tsuge
authors.forename: Barry
authors.initials: B
authors.lastname: Scott
mesh_terms: D001665:Binding Sites; D055329:Epichloe / Q000145:classification / Q000254:growth & development / Q000378:metabolism* / Q000502:physiology; D048690:Fruiting Bodies, Fungal; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D025301:Hyphae / Q000254:growth & development*; D008129:Lolium / Q000254:growth & development / Q000382:microbiology* / Q000502:physiology; D016254:Mutagenesis, Insertional; D018515:Plant Leaves / Q000382:microbiology*; D013559:Symbiosis
chemical_list: D005656:Fungal Proteins