Ancient horizontal transfer of a toxin biosynthesis cluster reveals novel mechanisms in the cercosporin biosynthesis pathway

M. Bolton, R. de Jonge, M.K. Ebert, B.P.H.J. Thomma

Research output: Chapter in Book/Report/Conference proceedingAbstract


Cercospora leaf spot (CLS) caused by the fungus Cercospora beticola is considered to be the most destructive foliar disease of sugarbeet worldwide. The ability of the fungus to cause disease relies primarily on the production of a toxin called cercosporin during infection. Cercosporin is a photo-activated secondary metabolite toxic to a wide array of organisms including bacteria, mice, and plants but not to cercosporin-producing Cercospora species. The cercosporin biosynthesis pathway has been well-characterized and thought to consist of eight cercosporin toxin biosynthesis (CTB) genes. We used phylogenomics to show that the CTB cluster is not limited to Cercospora species and has experienced an unprecedented number of duplications, losses, and horizontal transfers across a spectrum of plant pathogenic fungi during evolution. Since comparative genomic analysis revealed extensive gene collinearity adjacent to the established CTB cluster in all CTB-harboring species, we confirmed that CTB is larger than previously recognized and includes at least five additional genes, three of which are required for cercosporin biosynthesis. Additionally, the expanded cluster encodes the major facilitator superfamily transporter CFP, which contributes to cercosporin auto-resistance in C. beticola. Together, our results give new insight on the intricate evolution of the CTB cluster.
Original languageEnglish
Title of host publicationAbstract Book 29th Fungal Genetics Conference Asilomar 17, Pacific Grove, CA, USA 14-19 March 2017
PublisherGenetics Society of America
Publication statusPublished - 2 May 2017
Event29th Fungal Genetics Conference - Asilomar Conference Center, Pacific Grove, CA, United States
Duration: 14 Mar 201719 Mar 2017


Conference29th Fungal Genetics Conference
Country/TerritoryUnited States
CityPacific Grove, CA
Internet address


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