Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/22/2015
Publication Date: 3/22/2015
Citation: Proctor, R., Lee, T., Ward, T.J., Brown, D.W. 2015. Contributions of vertical descent, horizontal transfer and gene loss to the distribution of mycotoxin biosynthetic gene clusters in Fusarium [abstract].
Technical Abstract: The genus Fusarium produces a diverse array of mycotoxins and other secondary metabolites, but individual species contribute to only a small fraction of this diversity. Here, we employed comparative genomic and phylogenetic analyses to investigate the distribution and evolution of gene clusters responsible for production of four mycotoxin families (fumonisins, fusaric acid, fusarins, and trichothecenes) among species of Fusarium. The results indicate, not surprisingly, that the presence of a functional biosynthetic gene cluster is the major contributor to whether a species can produce the corresponding mycotoxin(s). The fusarin (FUS) cluster is widely but not uniformly distributed among Fusarium species, whereas the trichothecene (TRI) and fusaric acid (FUB) clusters have more limited distributions and their presence is more uniform within the multispecies lineages in which they occur. The fumonisin (FUM) cluster also exhibits a narrow distribution, but its presence within lineages is highly discontinuous. The results also indicate that vertical descent and independent cluster loss in lineages/species have been major contributors to the distribution of mycotoxin biosynthetic gene clusters among fusaria, whereas horizontal transfer (HT) between fusaria has had a more limited impact. We obtained evidence that HT between fusaria re-introduced the FUS cluster into a lineage that had lost the cluster relatively recently and introduced the FUB and FUM clusters into lineages that never had the clusters or had undergone ancient losses of them. Finally, the presence of distantly related homologs of the clusters in other genera of Hypocreales suggests that Fusarium acquired the clusters by vertical descent from a hypocrelean ancestor or by HT from another genus rather than by de novo cluster assembly in Fusarium after it diverged from other fungi.