|ALEXANDER, NANCY - RETIRED ARS EMPLOYEE|
|VILANI, ALESSANDRA - INSTITUTE OF FOOD SCIENCE AND TECHNOLGOY|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 9/15/2017
Publication Date: N/A
Technical Abstract: Fusarium is a species-rich genus of fungi that causes disease on most crop plants and produces diverse secondary metabolites (SMs), including some of the mycotoxins of greatest concern to food and feed safety. To determine the potential SM diversity within Fusarium as well as the distribution and evolution of mycotoxin biosynthetic gene clusters, we have assessed the presence and absence of SM biosynthetic gene clusters in genome sequences of >200 isolates representing 22 multi-species lineages (species complexes) and four single-species lineages of Fusarium. The results indicate that collectively Fusarium species have the genetic potential to produce hundreds of structurally distinct families of SMs, but that there is tremendous variation in distribution of SM clusters among species and lineages. Some clusters occur in one or a few lineages, while others occur in most lineages. Also, some SM clusters occur in most or all species within lineages, while others occur more sporadically in fewer species. Phylogenetic analyses suggest that differences in distribution have resulted from variation in vertical inheritance, horizontal transfer, and loss of clusters during the evolutionary diversification of Fusarium. Functional characterization of selected biosynthetic genes in Fusarium and other fungi indicate that variability in production of analogs of the same mycotoxin family can arise through acquisition, loss, and changes in functions of genes in the corresponding gene cluster. These findings add to a growing body of evidence that qualitative differences in mycotoxin production is affected by variation in presence and absence of clusters as well as variation in content and functions of genes within clusters.