Acquisition and Loss of Secondary Metabolites Shaped the Evolutionary Path of Three Emerging Phytopathogens of Wheat

Elisha Thynne, Oliver L. Mead, Yit Heng Chooi, Megan C. McDonald, Peter S. Solomon

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Abstract

White grain disorder is a recently emerged wheat disease in Australia, caused by Eutiarosporella darliae, E. pseudodarliae, and E. tritici-australis. The disease cycle of these pathogens and the molecular basis of their interaction with wheat are poorly understood. To address this knowledge gap, we undertook a comparative genomics analysis focused on the secondary metabolite gene repertoire among these three species. This analysis revealed a diverse array of secondary metabolite gene clusters in these pathogens, including modular polyketide synthase genes. These genes have only been previously associated with bacteria and this is the first report of such genes in fungi. Subsequent phylogenetic analyses provided strong evidence that the modular PKS genes were horizontally acquired from a bacterial or a protist species. We also uncovered a secondary metabolite gene cluster with three polyketide/nonribosomal peptide synthase genes (Hybrid-1, -2, and -3) in E. darliae and E. pseudodarliae. In contrast, only remnant and partial genes homologous to this cluster were identified in E. tritici-australis, suggesting loss of this cluster. Homologues of Hybrid-2 in other fungi have been proposed to facilitate disease in woody plants, suggesting a possible alternative host range for E. darliae and E. pseudodarliae. Subsequent assays confirmed that E. darliae and E. pseudodarliae were both pathogenic on woody plants, but E. tritici-australis was not, implicating woody plants as potential host reservoirs for the fungi. Combined, these data have advanced our understanding of the lifestyle and potential host-range of these recently emerged wheat pathogens and shed new light on fungal secondary metabolism.

Original languageEnglish
Pages (from-to)890-905
Number of pages16
JournalGenome Biology and Evolution
Volume11
Issue number3
DOIs
Publication statusPublished - 1 Mar 2019

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secondary metabolite
plant pathogens
secondary metabolites
Triticum
wheat
gene
Genes
woody plants
genes
woody plant
Fungi
Host Specificity
Multigene Family
multigene family
host range
fungi
pathogen
pathogens
fungus
Polyketide Synthases

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Thynne, Elisha ; Mead, Oliver L. ; Chooi, Yit Heng ; McDonald, Megan C. ; Solomon, Peter S. / Acquisition and Loss of Secondary Metabolites Shaped the Evolutionary Path of Three Emerging Phytopathogens of Wheat. In: Genome Biology and Evolution. 2019 ; Vol. 11, No. 3. pp. 890-905.
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Acquisition and Loss of Secondary Metabolites Shaped the Evolutionary Path of Three Emerging Phytopathogens of Wheat. / Thynne, Elisha; Mead, Oliver L.; Chooi, Yit Heng; McDonald, Megan C.; Solomon, Peter S.

In: Genome Biology and Evolution, Vol. 11, No. 3, 01.03.2019, p. 890-905.

Research output: Contribution to journalArticle

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T1 - Acquisition and Loss of Secondary Metabolites Shaped the Evolutionary Path of Three Emerging Phytopathogens of Wheat

AU - Thynne, Elisha

AU - Mead, Oliver L.

AU - Chooi, Yit Heng

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AU - Solomon, Peter S.

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