Magnesium represses trichothecene biosynthesis and modulates Tri5, Tri6, and Tri12 genes expression in Fusarium graminearum.
Growth and production of type-B trichothecenes mycotoxins by the Fusarium graminearum strain CBS 185.32 were compared in GYEP medium supplemented with Mg(2+) at different concentrations (0-4 mM). Mg(2+) led to a strong decrease in toxin accumulation without affecting the mycelial growth, suggesting a specific Mg(2+) effect on fungal secondary metabolism. Expression of Tri5, Tri6, and Tri12 genes was followed throughout the time courses of type-B trichothecenes (TCTB) yield in standard and 2 mM Mg(2+)-supplemented GYEP media. Mg(2+) addition significantly decreased Tri5, Tri6, and Tri12 expression. The inhibition of toxin production by Mg(2+ )was shown to be highly correlated with inhibition of Tri5 transcription and, to a lesser extend, of Tri6 and Tri12. This is the first report of a transcriptional control of TCTB production by Mg(2+).
Pinson-Gadais
Laetitia
L
INRA-Mycologie et Sécurité des Aliments, BP 81, 33883 Villenave D'Ornon, France. lpinson@bordeaux.inra.fr
Richard-Forget
Florence
F
Frasse
Pierre
P
Barreau
Christian
C
Cahagnier
Bernard
B
Richard-Molard
Daniel
D
Bakan
Bénédicte
B
D005656:Fungal Proteins / Q000235:genetics*; D005670:Fusarium / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects*; D008274:Magnesium / Q000494:pharmacology*; D012331:RNA, Fungal / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014255:Trichothecenes / Q000096:biosynthesis*
D005656:Fungal Proteins; D012331:RNA, Fungal; D014255:Trichothecenes; D008274:Magnesium