Grants and Contracts Details
Description
Tall fescue (Schedonorus arundinaceus) is an agronomical important cool season
grass that typically possesses the systemic symbiont, Epichloë coenophiala, a seed-borne fungal
endophyte that significantly increases plant resistance to insects, nematodes, drought and
stresses. The endophyte produces a cocktail of alkaloids that deter insects and perhaps
nematodes, but includes ergot alkaloids that cause episodes of toxicosis to cattle, horses and
other livestock. The resulting “fescue toxicosis” causes economic losses of ca. $1 billion
annually in the U.S. Genome sequencing of E. coenophiala has revealed two largely duplicate
clusters of ergot alkaloid biosynthesis genes, one of which (EAS1) is linked to the telomere at a
chromosome end, whereas the other (EAS2) is not. This information prompted us to develop a
chromosome-end “knockoff” technique that we used to trim off the EAS1 cluster. This technique
involved transiently incorporating a selectable marker, which was then lost from the
chromosome end to give a non-transgenic mutant. However, because some ergot alkaloids are
still produced by that mutant, we propose to employ the CRISPR approach to eliminate the key
gene for the first step in the pathway. Because E. coenophiala is asexual, doing so without
leaving any transgene presents a challenge, which may be addressed using our “knockoff”
technique with a destabilized selectable marker. If successful, the result will be precisely mutated
but non-transgenic E. coenophiala strains for new tall fescue cultivars that are suitable for
livestock while continuing to provide advantages to the plant. Furthermore, such a technique will
be widely applicable to other fungi.
Status | Finished |
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Effective start/end date | 1/1/19 → 6/30/20 |
Funding
- Mycological Society of America: $4,667.00
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