Page 285 - PC2019 Program & Proceedings

PLANT CANADA 2019

TOPIC 18: Molecular Host-Pathogen Interactions
(Posters P143-P154)

P143. Creation of pokeweed mosaic virus infectious clone to study host-pathogen interactions
*
Klenov, A. ; K. Hudak
York University

Potyviridae is a prolific plant virus family whose members cause significant damage to agricultural crops.
Potyviral genomes are ~10 kb ssRNA, and encode a polyprotein that is processed by viral proteases into
at least 11 multifunctional proteins. Phytolacca americana (American Pokeweed) produces pokeweed
antiviral protein (PAP) which has been shown to reduce replication of both plant and animal viruses by
depurinating RNA of the viral genomes. Curiously, pokeweed is infected in the wild by a potyvirus
known as Pokeweed mosaic virus (PkMV). To facilitate the identification of factors that overcome
pokeweed antiviral defence, the first infectious clone of PkMV was constructed by assembling sections of
the viral genome into a plant vector. Agroinfiltration of the clone into pokeweed leaves produced the
typical chlorotic mottling and systemic movement through the plant, indicative of infection by PkMV.
Viral particles isolated from plants inoculated with the infectious clone were morphologically identical to
PkMV, and presence of viral RNA and proteins were verified by RT-PCR and immunoblot assay. As
well, eGFP was cloned into the P1/HC-Pro junction to demonstrate the clone’s ability to be modified
while retaining infectious. The PkMV clone was engineered to contain PAP sequence which induced
reduction in PAP levels. After knocking down PAP, the susceptibility of the pokeweed plant to other
pathogens will be tested to expand our knowledge of PAP’s role in pokeweed.

Alexander Klenov (alexkle@yorku.ca)

P144. Monaghan Lab: Plant immunology and immune homeostasis
Monaghan, J.
Queen's University

Plants have evolved a multi-faceted immune system to fight against pathogen infection. While necessary
for survival, pathogen perception and the activation of immune responses are energetically taxing for the
host and have been linked to considerable fitness costs. Although defense signaling pathways must
therefore be tightly regulated, very little is known about the biochemical mechanisms that tailor signaling
to maintain cellular homeostasis. Our new research program at Queen’s University focuses on
understanding the basic mechanisms that allow plants to defend against a vast array of potential
pathogens while maintaining normal growth and development. To this end, our work address the
following biological questions using varied approaches: (1) What is the role of and interplay between
different post-translational modifications on proteins involved in immune homeostasis? (2) What are the
key regulators maintaining immune homeostasis and how do they function biochemically at the molecular
level? (3) What developmental pathways are affected by immune signaling? Understanding the
complexity of signaling events that underlie immune systems is integral to combating plant diseases that
threaten food security world-wide.

Jacqueline Monaghan (jm355@queensu.ca)

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