|LARABA, IMANE - Orise Fellow|
|AIME, CATHERINE - Purdue University|
|KOCH, RACHEL - Purdue University|
|WURDACK, KENNETH - Smithsonian Institute|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 8/15/2019
Publication Date: 8/15/2019
Citation: Laraba, I., Kim, H.-S., Vaughan, M.M., Busman, M., Proctor, R.H., O'Donnell, K., Aime, M.C., Koch, R.A., Wurdack, K.J. 2019. A novel Fusarium induces putative pseudoflowers on yellow-eyed grass (Xyris spp.) in Guyana [abstract].
Technical Abstract: We discovered a novel Fusarium species that produces putative pseudoflowers on three perennial species of Xyris (yellow-eyed grass) growing in the remote Cuyuni-Mararuni Region of Guyana. Fungal pseudoflowers were also found on herbarium specimens of Xyris collected in Venezuela and Columbia. A rosette of ultraviolet reflective petaloid structures that mimic host flowers in color, shape and size were produced on infected plants. This is the first report of a Fusarium producing pseudoflowers. Compared with pseudoflowers produced by Monilinia and Puccinia, those in Fusarium are unique in that they are entirely fungal. Multilocus molecular phylogenetic analyses of data mined from whole genome sequences resolved the novel Fusarium pathogen as sister to F. pseudocircinatum within the African clade of the F. fujikuroi species complex. The Xyris pathogen is phenotypically distinct from all other Fusarium species in that it produces abundant erect 0-septate microconidia-bearing synnemata up to 2 mm in height on carnation leaves. The potential of this pathogen to produce biologically active compounds, including phytohormones, pigments and mycotoxins, was assessed by conducing BLASTn searches of whole genome sequence data. Mycotoxin production was also assessed by liquid chromatography–mass spectrometry (LC-MS) analyses of strains cultivated in vitro on a solid medium. Results of a PCR assay for mating type revealed that MAT1-1 and MAT1-2 idiomorphs were both present on the flower-like rosettes on X. surinamensis and X. setigera; however, single conidial isolates only possessed one of the idiomorphs. We speculate that this putatively heterothallic fungus is deceiving unknown plant pollinators into vectoring microconidia of mating compatible strains to the same host plant. SEM images and results of a species-specific PCR assay revealed that the fungus had established a systemic infection in the sterilized plants that were producing floral mimics.