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Biochemical and molecular characterization of NADP-glutamate dehydrogenase from the ectomycorrhizal fungus Tuber borchii
Article first published online: 6 JUN 2002
DOI: 10.1046/j.1469-8137.2002.00409.x
1469-8137/asset/cover.gif?v=1&s=570a3a280b205b8cd6b43e7a8ee052e7536c7006 "New Phytologist")
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How to Cite
Vallorani, L., Polidori, E., Sacconi, C., Agostini, D., Pierleoni, R., Piccoli, G., Zeppa, S. and Stocchi, V. (2002), Biochemical and molecular characterization of NADP-glutamate dehydrogenase from the ectomycorrhizal fungus Tuber borchii. New Phytologist, 154: 779–790. doi: 10.1046/j.1469-8137.2002.00409.x
Publication History
- Issue published online: 6 JUN 2002
- Article first published online: 6 JUN 2002
- Received: 13 September 2001 Accepted: 21 January 2002
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Keywords:
- Tuber borchii;
- glutamate dehydrogenase;
- purification;
- gene cloning;
- expression analysis
Summary
• NADP-glutamate dehydrogenase (NADP-GDH) from Tuber borchii was purified and the corresponding gene was cloned in order to elucidate the physiological role of the enzyme in this ectomycorrhizal fungus.
• NADP-GDH was purified using an anion-exchange column followed by affinity chromatography. The complete gene was cloned from a 30-d-old-mycelium cDNA library and characterized.
• T. borchii NADP-GDH appears to be physically and kinetically similar to those from other fungi and the deduced amino acid sequence of the gdh gene showed a significant similarity to other fungal NADP-dependent GDHs. Biochemical and Northern blotting analyses carried out with mycelia grown on different nitrogen sources clearly showed that the regulation of T. borchii NADP-GDH in response to different nitrogen sources was markedly different from the responses of the NADP-GDHs of other ascomycetes. Northern blotting analyses highlighted that the gdh gene was also expressed in the symbiotic phase.
• The biochemical and molecular data suggest that the fungal NADP-GDH contributes to the primary nitrogen metabolism in the ectomycorrhizal tissues.