African Journal of
Microbiology Research

  • Abbreviation: Afr. J. Microbiol. Res.
  • Language: English
  • ISSN: 1996-0808
  • DOI: 10.5897/AJMR
  • Start Year: 2007
  • Published Articles: 5230

Characterization of a cytochrome P450 monooxygenase gene involved in the biosynthesis of geosmin in Penicillium expansum

Muhammad Hussnain Siddique1,2, Thierry Liboz1,2, Nafees Bacha3, Olivier Puel4, Florence Mathieu1,2 and Ahmed Lebrihi1,2,5*      
1Université de Toulouse, INPT-UPS, Laboratoire de Génie Chimique, avenue de l’Agrobiopole, 31326 Castanet-Tolosan Cedex, France. 2Le Centre national de la recherche scientifique (CNRS), Laboratoire de Génie Chimique, 31030 Toulouse, France. 3Centre of Biotechnology and Microbiology, University of Peshawar, Pakistan. 4Institut National de la Recherche Agronomique (INRA), Laboratoire de Pharmacologie Toxicologie, 31931 Toulouse, France. 5Université Moulay Ismail, Marjane 2, BP 298, Meknes, Morocco.  
Email: [email protected]

  •  Accepted: 14 February 2012
  •  Published: 23 May 2012


Geosmin is a terpenoid, an earthy-smelling substance associated with off-flavors in water and wine. The biosynthesis of geosmin is well characterized in bacteria, but little is known about its production in eukaryotes, especially in filamentous fungi. The origin of geosmin in grapevine is largely attributable to the presence of Penicillium expansum on grapes. Herein, we describe the characterization of “gpe1”, a gene encoding a cytochrome P450 monooxygenase probably involved in the biosynthesis of geosmin in this species. A gpe1knockout mutant of P. expansum M2230 lost the capacity to produce geosmin, while the genetically complemented mutant restored it. The deduced gpe1 protein sequence shows identities with other cytochrome P450 monooxygenases involved in diterpene biosynthesis. These enzymes catalyze the addition of hydroxyl groups to the diterpene compounds. gpe1protein could work in the same way, with sesquiterpenes as substrates. This gene seems to be only present in geosmin-producing Penicillium species. To our knowledge, this is the first characterization of a fungal gene encoding an enzyme involved in geosmin biosynthesis.


Key words: Penicillium expansum, cytochrome P450 monooxygenase, geosmin.