title: CLM1 of Fusarium graminearum encodes a longiborneol synthase required for culmorin production.
abstract: Fusarium graminearum is a fungal pathogen of cereal crops (e.g., wheat, barley, maize) and produces a number of mycotoxins, including 15-acetyldeoxynivalenol, butenolide, zearalenone, and culmorin. To identify a biosynthetic gene for the culmorin pathway, an expressed-sequence-tag database was examined for terpene cyclase genes. A gene designated CLM1 was expressed under trichothecene-inducing conditions. Expression of CLM1 in yeast (Saccharomyces cerevisiae) resulted in the production of a sesquiterpene alcohol, longiborneol, which has the same ring structure as culmorin. Gene disruption and add-back experiments in F. graminearum showed that CLM1 was required for culmorin biosynthesis. CLM1 gene disruptants were able to convert exogenously added longiborneol to culmorin. Longiborneol accumulated transiently in culmorin-producing strains. The results indicate that CLM1 encodes a longiborneol synthase and is required for culmorin biosynthesis in F. graminearum.
authors.affiliation: Mycotoxin Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, U.S. Department of Agriculture, 1815 N. University, Peoria, IL 61604, USA. Susan.McCormick@ars.usda.gov
authors.forename: S P
authors.initials: SP
authors.lastname: McCormick
authors.forename: N J
authors.initials: NJ
authors.lastname: Alexander
authors.forename: L J
authors.initials: LJ
authors.lastname: Harris
mesh_terms: D053898:Biosynthetic Pathways; D003001:Cloning, Molecular; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D030541:Databases, Genetic; D020224:Expressed Sequence Tags; D005670:Fusarium / Q000201:enzymology* / Q000235:genetics; D017353:Gene Deletion; D015870:Gene Expression; D005816:Genetic Complementation Test; D008025:Ligases / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D015394:Molecular Structure; D016254:Mutagenesis, Insertional; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D012717:Sesquiterpenes / Q000378:metabolism*
chemical_list: D004271:DNA, Fungal; D012717:Sesquiterpenes; C013900:culmorin; C412581:longiborneol; D008025:Ligases