Page 157 - PC2019 Program & Proceedings

PLANT CANADA 2019

S99. Control of plant fungal pathogens using exogenous RNA
E. Liu; U. Hemraz; S. Dodard; Y. Liu; S. Hrapovic; Clark, S.
National Research Council Canada

Fungal pathogens represent one of the greatest threats to the global food supply. While some pathogens
can be effectively controlled through plant based resistance fungicides are required to control several
prominent fungi. The wide spread use of fungicides has adverse environmental consequences and can
lead to fungicide resistance. Plant RNAi expression can silence genes in closely associated pathogenic
fungi in a phenomenon known as host induced gene silencing. While this strategy has been demonstrated
for a wide range of fungi it requires the use of genetic modification that is not accepted in many important
crop species. Here we explored the use of exogenous RNA applications to provide plant protection
without the need for genetic modification. Data will be presented for the control of Fusarium
graminearum and Botrytis cinerea. We have found that the targeting of essential chitin synthase genes
can significantly reduce infection with quantitative real-time PCR confirming silencing of target fungal
transcripts. The data for targeting additional fungal genes will also be presented. We are also evaluating
the use of nanomaterials for the encapsulation of RNA to improve stability and uptake and progress in
this area will be discussed. The development of RNA based fungicides will provide a new tool for the
control fungi that would allow precise targeting of fungal pathogens.

Shawn Clark (Shawn.Clark@nrc.ca)

S100. Multi-omic studies reveal the insertion of new mycotoxin virulence factors in Fusarium poae.
1
3
1
1
2
1
Overy, D. ; T. Witte ; A. Sproule ; A. Hermans ; A. Johnston ; A. Xue ; J. Dettman ;
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H. Nguyen ; L. Harris 1
1
1 Ottawa Research and Development Centre
2 Ottawa Research and Development Centre
3 AAFC
Fusarium poae (Peck) Wollenweber is cosmopolitan, occurring on a range of hosts and associated with
Fusarium Head Blight (FHB) in cereals. Extensive sampling of oat, barley, and wheat heads infected with
FHB from Ontario, Quebec and Saskatchewan fields (from 2006 – 2016) confirmed that F. poae and F.
graminearum Schwabe are the main Fusaria isolated from barley while F. poae is predominant
contaminating oats. Historically, mycotoxin production associated with F. poae in Europe is quite
variable and little is known about the mycotoxigenic potential of Canadian isolates. Several researchers
hypothesize that the variation in mycotoxin expression observed in F. poae results from the presence of
supernumerary chromosomes and the abundance of transposable elements (TEs) within its
genome. Supernumerary chromosomes act as evolutionary cradles for pathogen virulence factors and
transposon facilitated translocations into core chromosomes can accelerate genome evolution and
therefore present a considerable challenge towards a durable disease management strategy. In depth
metabolomic profiling and genome sequencing was carried out on 46 monosporic Canadian F. poae
isolates demonstrating a degree of chemotypic diversity. Metabolomic profiling revealed consistent
production of multiple “core genome” associated metabolites including the emerging mycotoxins
diacetoxyscirpenol and beauvericin. Of particular interest, strain specific production of new mycotoxins
and potential virulence factors were also observed and linked with horizontal gene transfer through
supernumerary insertions into the F. poae genome.

David Overy (david.overy@canada.ca)

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