Screening of putative oxygenase genes in the Fusarium graminearum genome sequence database for their role in trichothecene biosynthesis.
In the biosynthesis of type B trichothecenes, four oxygenation steps remain to have genes functionally assigned to them. On the basis of the complete genome sequence of Fusarium graminearum, expression patterns of all oxygenase genes were investigated in Fusarium asiaticum (F. graminearum lineage 6). As a result, we identified five cytochrome P450 monooxygenase (CYP) genes that are specifically expressed under trichothecene-producing conditions and are unique to the toxin-producing strains. The entire coding regions of four of these genes were identified in F. asiaticum. When expressed in Saccharomyces cerevisiae, none of the oxygenases were able to transform trichodiene-11-one to expected products. However, one of the oxygenases catalyzed the 2beta-hydroxylation rather than the expected 2alpha-hydroxylation. Targeted disruption of the five CYP genes did not alter the trichothecene profiles of F. asiaticum. The results are discussed in relation to the presence of as-yet-unidentified oxygenation genes that are necessary for the biosynthesis of trichothecenes.
Tokai
Takeshi
T
Laboratory for Remediation Research, and Plant and Microbial Metabolic Engineering Unit-Laboratory, Plant Science Center (PSC1) and Discovery Research Institute, RIKEN, Wako, Saitama 351-0198, Japan.
Koshino
Hiroyuki
H
Kawasaki
Tsuneomi
T
Igawa
Tomoko
T
Suzuki
Yoshikatsu
Y
Sato
Masayuki
M
Fujimura
Makoto
M
Eizuka
Takayoshi
T
Watanabe
Hidenori
H
Kitahara
Takeshi
T
Ohta
Kunihiro
K
Shibata
Takehiko
T
Kudo
Toshiaki
T
Inoue
Hirokazu
H
Yamaguchi
Isamu
I
Kimura
Makoto
M
D004271:DNA, Fungal / Q000032:analysis / Q000235:genetics; D030541:Databases, Genetic; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D005670:Fusarium / Q000145:classification / Q000201:enzymology* / Q000235:genetics; D016681:Genome, Fungal; D010105:Oxygenases / Q000235:genetics* / Q000378:metabolism; D014255:Trichothecenes / Q000096:biosynthesis* / Q000737:chemistry / Q000378:metabolism
D004271:DNA, Fungal; D005656:Fungal Proteins; D014255:Trichothecenes; D010105:Oxygenases