ABSTRACT
The Tri5 gene encodes trichodiene synthase, which catalyzes the first reaction in the trichothecene biosynthetic pathway. In vitro, a direct relationship was observed between Tri5 expression and the increase in deoxynivalenol production over time. We developed a reverse transcription (RT)-PCR assay to quantify Tri5 gene expression in trichothecene-producing strains of Fusarium species. We observed an increase in Tri5 expression following treatment of Fusarium culmorum with fungicides, and we also observed an inverse relationship between Tri5 expression and biomass, as measured by beta-D-glucuronidase activity, during colonization of wheat (cv. Avalon) seedlings by F. culmorum. RT-PCR analysis also showed that for ears of wheat cv. Avalon inoculated with F. culmorum, there were different levels of Tri5 expression in grain and chaff at later growth stages. We used the Tri5-specific primers to develop a PCR assay to detect trichothecene-producing Fusarium species in infected plant material.
Subject(s)
Carbon-Carbon Lyases/genetics , Fusarium/enzymology , Fusarium/genetics , Gene Expression , Plant Diseases/microbiology , Reverse Transcriptase Polymerase Chain Reaction/methods , Triticum/microbiology , Antifungal Agents/pharmacology , Carbon-Carbon Lyases/biosynthesis , DNA, Fungal/analysis , Fusarium/drug effects , Fusarium/isolation & purification , Triazoles/pharmacology , Trichothecenes/metabolismABSTRACT
Ten random amplified polymorphic DNA (RAPD) markers specific to chromosome 5E(b) of Thinopyrum bessarabicum were detected. Genomic in situ hybridization and standard cytological observations revealed that six of the markers are located on the 5E(b) short arm and four are located on the 5E(b) long arm. These RAPD markers have been used to confirm the identity of putative 5E(b) (5A) and 5E(b) (5D) substitution individuals. The potential of RAPDs for the detection of wheat/alien recombinants is discussed.
