Title: Quantification of trichothecene biosynthetic genes during the growth cycle of Fusarium sporotrichioides in culture Authors
Submitted to: Fungal Genetics Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: December 31, 2007
Publication Date: April 15, 2008
Citation: Alexander, N.J., Mc Cormick, S.P. 2008. Quantification of trichothecene biosynthetic genes during the growth cycle of Fusarium sporotrichioides in culture [abstract]. 9th European Conference on Fungal Genetics. p. 134. Technical Abstract: Trichothecene mycotoxins are secondary metabolites produced by several species of phytopathogenic fungi, and are potent inhibitors of protein biosynthesis. The genes involved in the biosynthetic pathway of T-2 toxin in Fusarium sporotrichioides have been characterized and are located in four identified loci. We wished to determine when these genes were turned on in the metabolic cycle, and in what quantity. RNA was harvested at 8, 12, 16, and 24 hours after inoculation with spores of F. sporotrichioides in a defined, liquid medium. Reverse transcriptase was used to form cDNA, and quantitative polymerase chain reaction (qPCR) was performed using primers specific to selected trichothecene biosynthetic genes. Trichothecene genes were transcribed between 12 and 16 hours post inoculation, typical of secondary metabolite genes, while basic metabolic genes were detected earlier at 8 hours. As the expression of the trichothecene genes rise, the expression of the basic housekeeping genes declines. FsTri4 and FsTri5 are the most highly expressed trichothecene genes, with seven-fold greater expression than FsTri1, FsTri13, and FsTri15. FsTri15, a gene involved in the negative regulation of the pathway, has a delayed profile. Together, these and other data indicate that the level of expression of each of the trichothecene pathway genes is unique. This may lead to a novel method for controlling the expression of this pathway, with the ultimate goal of reducing the presence of these mycotoxins in our food and feed supply.