Page 133 - Plant Canada 2024 Proceeding

PLANT CANADA 2024

However, RNA-Seq and hormone profiling data revealed that jasmonate rather than salicylate
biosynthesis is upregulated in C. harknessii-inoculated lodgepole and jack pine. Interestingly, levels of
jasmonate-isoleucine, the active form of jasmonate, did not increase in these plants. Drawing from recent
research in angiosperm pathosystems, we speculate that C. harknessii may act to upregulate jasmonate
biosynthesis, possibly as a means to suppress salicylate signalling and thereby decrease host immunity
against this biotroph.

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*[O63] DO GINSENOSIDES ALTER THE PATHOGENICITY OF ILYONECTRIA? Anka Colo and Mark
A. Bernards . Department of Biology, Western University, 1151 Richmond Street, London, ON, Canada,
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N6A 3K7
Correspondence to: acolo@uwo.ca

American ginseng, Panax quinquefolius L., is an economically valuable crop used in Traditional Chinese
Medicine; however, yield of ginseng is negatively impacted by ginseng replant disease (GRD). GRD is
characterized by a severe root rot, primarily caused by the fungus Ilyonectria mors-panacis (Imp)
(formerly Cylindrocarpon destructans), in ginseng planted in a former-ginseng garden. While Imp is
typically present in ginseng garden soils during the first cultivation of a ginseng crop, Imp-associated root
rot is more extensive during subsequent crop plantings. Furthermore, the bioactive ginsenoside
compounds produced by ginseng accumulate in ginseng garden soils during cultivation and are known to
be fungitoxic toward some soil-borne fungi, while growth stimulants of others, including Imp. Presently, it
is not clear if (1) prior exposure to ginsenosides enhances Ilyonectria virulence, (2) different Ilyonectria
isolates can metabolize ginsenosides equally effectively, and (3) there is a relationship between
Ilyonectria virulence and the metabolism of ginsenosides. To address these issues, twelve independent
Ilyonectria isolates that differ in their geographic and host plant origins, were screened for their
pathogenicity toward American ginseng. For this, one-year old American ginseng seedlings were
inoculated separately with twelve Ilyonectria isolates and monitored for disease onset using non-invasive
chlorophyll fluorescence detection over 28-days. Disease load was scored at 28-days. Five Ilyonectria
isolates displayed low virulence while seven Ilyonectria isolates displayed high virulence. To address the
question of whether prior exposure to ginsenosides affects Ilyonectria virulence on ginseng, two-year old

American ginseng roots were inoculated with different isolates of Ilyonectria from both the low and high
virulence groups that had been cultivated on media with and without ginsenosides. After 16-days, lesions
were measured. Two low virulent isolates showed increased virulence (i.e., greater lesion size) after
being grown on ginsenoside containing media for a minimum of four transfers, while the virulence of high
virulent isolates remained unchanged by ginsenoside treatment. These data suggest that exposure to
ginsenosides increase the virulence of Ilyonectria toward American ginseng. Lastly, to determine whether
Ilyonectria isolates can metabolize ginsenosides equally effectively, we are currently growing Ilyonectria
isolates in liquid minimal media supplemented with ginsenosides and will use liquid chromatography–
mass spectrometry (LCMS) used to quantify the ginsenosides remaining after seven days. Understanding
whether exposure to ginsenosides enhances virulence will further our understanding of Ilyonectria and its
implications in GRD.

[O64] PLANT IMMUNE RESILIENCE: FROM GENE REGULATORY NETWORKS TO BIOMOLECULAR
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CONDENSATES. Christian Danve M. Castroverde , Jong Hum Kim , Alyssa Shields , Lingya Yao , Shuai
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6
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Huang , Eric J.R. Marchetta , Richard Hilleary , Adam Seroka , John D. MacMicking , Xiu-Fang Xin , and
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Sheng Yang He . Department of Biology, Wilfrid Laurier University, Waterloo, ON, Canada, N2L 3C5;
2 Department of Life Sciences, Pohang University of Science and Technology, Pohang, 37673, Republic of
3
Korea; National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular
Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai
200032, China; Department of Molecular Genetics, The Ohio State University, Columbus, OH, USA
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43210; Howard Hughes Medical Institute, Department of Biology, Duke University, Durham, NC, USA
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27708; and Howard Hughes Medical Institute, Departments of Immunobiology and Microbial
Pathogenesis, Yale University School of Medicine, New Haven, CT, USA 06477
Correspondence to: dcastroverde@wlu.ca

Climate warming negatively affects diverse aspects of plant life, including effective immune signaling and
responses. Two central plant immune-activating signals are salicylic acid (SA) and N-hydroxypipecolic
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