Page 151 - Plant Canada 2024 Proceeding

PLANT CANADA 2024

higher proportion of PPT passed through the soil than PPD, with the majority of ginsenosides eluted
within the first four weeks. At lower concentrations of applied ginsenosides, PPD bound more readily to
the upper portion of the soil column, whereas at higher concentrations, PPD was found throughout the
entire column. In summary, PPD exhibits stronger binding to soil than PPT, while PPT showed greater
mobility in ginseng garden soil. These findings provide insight into ginsenoside dynamics in soil and allow
a better understanding of their potential role in ginseng garden soils and their contribution to GRD.

[O98] INTERACTIONS BETWEEN APHANOMYCES EUTEICHES AND FUSARIUM AVENACEUM
1
2
2
AND GRAMINEARUM. Michelle Hubbard , Olivia Zajac , Anas Eranthodi , Syama Chatterton , David
1
3
2 1
Overy , and Nora Foroud . Swift Current Research and Development Centre, Agriculture and Agri-Food
Canada, 1 Airport Rd, Swift Current, SK, Canada, S9H 3X2; Lethbridge Research and Development
2
st
Centre, Agriculture and Agri-Food Canada, 5403 1 Ave S, Lethbridge, AB, Canada, T1K 6M5; and
3 Ottawa Research and Development Centre, Agriculture and Agri-Food Canada, 960 Carling Avenue,
Ottawa, ON, Canada, K1A 0C6
Correspondence to: michelle.hubbard@agr.gc.ca

Root rot can severely limit pea and lentil production. This disease is caused by a complex of pathogens,
including Aphanomyces euteiches (Ae), Fusarium avenaceum (Fa) and F. graminearum, (Fg) as well as
other Fusarium species, Pythium species and Rhizoctonia solani. Root rot tends to be more severe when
Ae and F. redolens or F. solani are present, relative to any of the three alone. However, co-infection with
Ae and Fa has not been shown to increase root rot severity and the impact of Fg on Ae root rot has not
been explored. Both Fa and Fg produce various mycotoxins (secondary metabolites) that include the
enniatins from Fa and deoxynivalenol (DON) from Fg. We aimed to explore the impacts of co-occurrence
of Fa and Fg and their fore mentioned mycotoxins on the growth of Ae in vitro and on root rot of peas.
Mutant strains of Fa that overexpress (OX) or are deficient (KO) for enniatin production (FaOX and FaKO,
respectively), and a mutant strain of Fg that is deficient in DON production (Fgtri5-) and wildtype (WT)
strains of both organisms (FaWT and FgWT) were used. From in vitro experiments using Petri plate
cultures where Ae was placed in the centre of the plate, and four agar plugs of the Fusarium isolate in
question were placed equidistant from Ae, FaWT and FaOX reduced Ae radial growth, while the FaKO
(loss of enniatin production) did not. In vitro assays involving commercially available enniatins reduced Ae
radial growth and oospore production. The FgWT strain also reduced Ae growth; surprisingly, the FgTri5-
mutant (deficient in DON production) had an even stronger impact, suggesting that other factors likely
also contribute to the Fg/Ae interaction. However, when culture filtrate from FgTri5- was added to solid
media on which Ae was grown, Ae growth was not inhibited. The reverse was true of culture filtrate from
FgWT. In vermiculite, but not in soil, Ae+FgWT and Ae+Fgtri5- both reduced root rot severity relative to Ae
inoculation alone. Thus, it appears that interactions between Ae and Fa and Fg are complex, and largely,
but not entirely, dependant on secondary metabolites.

[O99] PRESCREENING AND MONITORING EVALUATION USING SEQUENCING TECHNOLOGIES
2
1
FOR PHYTOPHTHORA AND OOMYCETES. Guillaume J. Bilodeau and Hervé Van der Heyden .
1 Canadian Food Inspection Agency, Ottawa Laboratory Fallowfield, Ottawa plant laboratory, Ottawa, On,
2
Canada, K2H 8P9; and Agriculture and Agrifood Canada, Saint-Jean-sur-Richelieu Research and
Development Centre, 430 Gouin Blvd, Saint-Jean-sur-Richelieu, Qc, Canada, J3B 3E6
Correspondence to: Guillaume.Bilodeau@inspection.gc.ca

Metagenomics can provide insightful information on species diversity and improve surveillance of
introduced species. While isolation and bating could underestimate species diversity, high throughput
sequencing can be used as a new tool for early detection of oomycetes, including Phytophthora species,
endemic or regulated and invasive alien species, that can cause major diseases in agricultural and forest
ecosystems. High throughput sequencing (HTS) technologies allow us to investigate different sample
types, process large numbers of samples, and produce even greater volumes of genomic data.
Metabarcoding tools on different genetic regions and combining Ion Torrent or Oxford Nanopore
sequencing and custom bioinformatics pipelines can be used to evaluate potential sampling schemes for
pathogens in forestry and agriculture and help identify dispersal and spreading pathways. Sampling
methods exploiting eDNA isolated from air, soil, and tissues revealed sources of oomycetes likely to
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