The Tri4 gene of Fusarium sporotrichioides encodes a cytochrome P450 monooxygenase involved in trichothecene biosynthesis.

摘要: TheTri4 gene ofFusarium sporotrichioides was isolated from a cloned DNA fragment carrying theTri5 by complementation of aTri4− mutant. The nucleotide sequence ofTri4 determined and the locations three introns were identified. Analysis mRNA levels revealed that transcription reached maximum coincidently with onset trichothecene biosynthesis, then declined 20-fold over next 8 h. Disruption resulted in loss production both trichothecenes apotrichodiol accumulation unoxygenated pathway intermediate trichodiene. Transformants lacking functionalTri4 able to convert isotrichotriol, an early intermediate, T-2 toxin suggesting most enzymes are present inTri4− mutants. These data suggest enzyme encoded byTri4 catalyzes first oxygenation step participates biosynthesis.Tri4 encodes protein 520 residues (Mr=59 056) shows significant homology members superfamily cytochromes P450. It appears similar CYP3A subfamily (24.6% amino acid identity). Because it contains less than 40% positional identity other P450, theTri4 has been placed new cytochrome P450 family designatedCY P58.