RT Journal Article SR Electronic T1 Conservation of a gene cluster reveals novel cercosporin biosynthetic mechanisms and extends production to the genus Colletotrichum JF bioRxiv FD Cold Spring Harbor Laboratory SP 100545 DO 10.1101/100545 A1 Ronnie de Jonge A1 Malaika K. Ebert A1 Callie R. Huitt-Roehl A1 Paramita Pal A1 Jeffrey C. Suttle A1 Rebecca E. Spanner A1 Jonathan D. Neubauer A1 Wayne M. Jurick II A1 Karina A. Stott A1 Gary A. Secor A1 Bart P.H.J. Thomma A1 Yves Van de Peer A1 Craig A. Townsend A1 Melvin D. Bolton YR 2017 UL http://biorxiv.org/content/early/2017/07/25/100545.abstract AB Species in the genus Cercospora cause economically devastating diseases in sugar beet, maize, rice, soy bean and other major food crops. Here we sequenced the genome of the sugar beet pathogen C. beticola and found it encodes 63 putative secondary metabolite gene clusters, including the cercosporin toxin biosynthesis (CTB) cluster. We show that the CTB gene cluster has experienced multiple duplications and horizontal transfers across a spectrum of plant pathogenic fungi, including the wide host range Colletotrichum genus as well as the rice pathogen Magnaporthe oryzae. Although cercosporin biosynthesis has been thought to-date to rely on an eight gene CTB cluster, our phylogenomic analysis revealed gene collinearity adjacent to the established cluster in all CTB cluster-harboring species. We demonstrate that the CTB cluster is larger than previously recognized and includes cercosporin facilitator protein (CFP) previously shown to be involved with cercosporin auto-resistance, and four additional genes required for cercosporin biosynthesis including the final pathway enzymes that install the unusual cercosporin methylenedioxy bridge. Finally, we demonstrate production of cercosporin by Colletotrichum fioriniae, the first known cercosporin producer within this agriculturally important genus. Thus, our results provide new insight into the intricate evolution and biology of a toxin critical to agriculture and broaden the production of cercosporin to another fungal genus containing many plant pathogens of important crops worldwide.Significance Statement Species in the fungal genus Cercospora cause diseases in many important crops worldwide. Their success as pathogens is largely due to the secretion of cercosporin during infection. We report that the cercosporin toxin biosynthesis (CTB) cluster is ancient and was horizontally transferred to diverse fungal pathogens on an unprecedented scale. Since these analyses revealed genes adjacent to the established CTB cluster, we evaluated their role in C. beticola to show that four are necessary for cercosporin biosynthesis. Finally, we confirmed that the apple pathogen Colletotrichum fioriniae produces cercosporin, the first case outside the family Mycosphaerellaceae. Other Colletotrichum plant pathogens also harbor the CTB cluster, which points to a wider concern that this toxin may play in virulence and human health.