Multiple metabolic pathways for metabolism of L-tryptophan in Fusarium graminearum

Fusarium graminearum is a plant pathogen that can cause the devastating cereal grain disease fusarium head blight (FHB) in temperate regions of the world. Previous studies have shown that F. graminearum can synthetize indole-3-acetic acid (auxin) using L-tryptophan (L-TRP)-dependent pathways. In the present study, we have taken a broader approach to examine the metabolism of L-TRP in F. graminearum liquid culture. Our results showed that F. graminearum was able to transiently produce the indole tryptophol when supplied with L-TRP. Comparative gene expression profiling between L-TRP-treated and control cultures showed that L-TRP treatment induced the up-regulation of a series of genes with predicted function in the metabolism of L-TRP via anthranilic acid and catechol towards the tricarboxylic acid cycle. It is proposed that this metabolic activity provides extra energy for 15-acetyldeoxynivalenol production, as observed in our experiments. This is the first report of the use of L-TRP to increase energy resources in a Fusarium species.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author