Page 61 - PC2019 Program & Proceedings

PLANT CANADA 2019

PS8. Wednesday, July 10, morning session at 9:20 am

Dr. Richard R. Bélanger

Université Laval, Québec, QC

A unique interaction with a biocontrol agent alters the
parasitic activity of powdery mildews on plants

Abstract: The phyllosphere harbors a diverse microbial community in which fungi occupy a predominant
space. In the course of evolution, all leaf surface fungi have acquired specific properties that enable them to
compete and survive in this restricted ecological niche in spite of the apparent limited resources on the leaf.
While we, as scientists, have been trying to ascribe a certain hierarchy among the fungi inhabiting the
phylloplane, it is nonetheless important to remember that in a balanced environment, each of these fungi
manages successfully to acquire the resources necessary for its establishment and reproduction on the leaf
surface. For instance, recent observations have highlighted that closely related organisms co-habit in this
environment with albeit quite different lifestyles. Among them, the Ustilaginaceae, including the genera
Ustilago and Pseudozyma, comprise members that can be plant pathogens, biocontrol agents, or simple
epiphytes. Comparative genomic analyses among different members of the Ustilaginaceae have revealed that
these opposite lifestyles in similar environments are seemingly associated with the presence/absence of a very
limited number of genes coding mostly for effector proteins. In the same manner, the members lacking the
effector proteins to be a plant pathogen, for example, seem to have acquired specific features, including their
own unique set of effectors, to adopt a different lifestyle. These complex and subtle evolutive processes appear
to play key roles in the adaption of fungi occupying specific ecological niches, and in their ability to extract
resources necessary for their survival in a given environment.

Bio:

Dr. Richard Bélanger is full professor in plant pathology and holder of a Canada Research Chair in plant protection
at Laval University. His research endeavors concentrate on the development of biological and non-chemical
approaches to control plant diseases. Along those lines, sustained efforts have been devoted toward biological
control of powdery mildews with natural antagonists. Belanger’s lab has pioneered the exploitation of the fungus
Pseudozyma flocculosa and its unique properties to attack powdery mildews. This research has led the way to
the development of a commercial product and to the elucidation of an unusual tritrophic interaction where the
plant, the pathogen and the biocontrol fungus each contributes coordinated factors leading to the collapse of
the pathogen.

Département de phytologie, Université Laval

2425, rue de l'Agriculture, Québec, Qc, G1V0A6, Canada

Richard.Belanger@fsaa.ulaval.ca

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