Characterization and mRNA expression profile of the TbNre1 gene of the ectomycorrhizal fungus Tuber borchii

• Published in: Current genetics Vol. 55; no. 1; pp. 59 - 68
• Main Authors: Guescini, Michele, Stocchi, L., Sisti, D., Zeppa, S., Polidori, E., Ceccaroli, P., Saltarelli, R., Stocchi, V.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.02.2009; Springer Nature B.V
• Subjects: Amino Acid Sequence; Ammonium; Ascomycota - genetics; Ascomycota - growth & development; Ascomycota - metabolism; Biochemistry; Biomedical and Life Sciences; Blotting, Southern; Cell Biology; Cloning; Cloning, Molecular; Complementation; Data processing; DNA, Fungal; Ectomycorrhizas; Fungal Proteins - genetics; Gene expression; Gene Expression Profiling; Gene Expression Regulation, Fungal - physiology; Glutamine; Life Sciences; Microbial Genetics and Genomics; Microbiology; Molecular Sequence Data; Mycelium - cytology; Mycelium - metabolism; Mycorrhizae - genetics; Neurospora crassa; Nitrate; Nitrogen; Nitrogen - metabolism; Nitrogen sources; PII Nitrogen Regulatory Proteins - genetics; Plant Sciences; Polymerase chain reaction; Protein turnover; Proteinase; Proteomics; Recombinant Proteins - genetics; Recombinant Proteins - isolation & purification; Recombinant Proteins - metabolism; regulatory proteins; Research Article; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger - metabolism; Sequence Homology, Amino Acid; Transcription factors; Tuber borchii; Tubers; Up-Regulation; Zinc-finger transcription factor; Ectomycorrhizae; Nitrogen limitation; Gene regulation
• ISSN: 0172-8083; 1432-0983
• DOI: 10.1007/s00294-008-0222-x

This study focuses on the cloning and characterization of the major nitrogen regulator element from the ectomycorrhizal fungus Tuber borchii, TbNre1 . Sequence analysis of the predicted protein and complementation experiments in Neurospora crassa demonstrated that the cloned gene is orthologous to areA/nit-2 gene. Transcriptional expression investigations by real-time RT-PCR showed TbNre1 up-regulation in the presence of nitrate or in the absence of nitrogen during free-living mycelium growth. On the contrary, TbNre1 mRNA levels remained at basal values in the presence of preferred nitrogen sources like ammonium and glutamine. Furthermore, TbNre1 mRNA was found to be up-regulated during T. borchii and T. platyphyllos interaction. All these data suggest that the regulatory protein TBNRE1 could play a major role in regulating N metabolism genes of T. borchii in the free living mycelium and in T. borchii – T. platyphyllos interaction. Finally, the possible role of the transcription factor TBNRE1 in the induction of proteases and virulence-like genes, necessary in ectomycorrhizal establishment, was also discussed.