Page 153 - PC2019 Program & Proceedings

PLANT CANADA 2019

S91. Microhazels: A novel industry for Ontario agriculture
Shukla, M.; P. Saxena
University of Guelph

Hazelnut cultivation has a tremendous potential for bringing immediate and long-term benefits to Ontario
agriculture due to the rapidly increasing demand for hazelnuts by Ferrero Canada and other food
industries. Lack of disease-free plant materials coupled with time-consuming propagation technologies
have restricted the introduction of new hazelnut cultivars. In vitro technologies such as micropropagation
can be used to multiply plants from an existing population in large numbers to distribute plants with
greater expediency. Micropropagation allows plants to be multiplied exponentially and since they are
grown in aseptic culture conditions, plants are healthy and genetically uniform. We have developed
efficient protocols for large-scale micropropagation using liquid based bioreactor systems.
Cryopreservation, a process of maintaining tissues in liquid nitrogen at -196̊ C allows for disease
elimination and conservation of genetic resources. A novel approach has been developed by shifting the
emphasis on optimizing explant physiology and enabling them to withstand stresses of dehydration and
temperature changes to improve cryopreservation. The Integrated Plant Production System (IPPS), which
combines plant propagation in vitro, acclimation in the greenhouse, and field transplantation, would
facilitate delivery of certified, clean plants that are adapted to Ontario climate to satisfy local demand as
well as open new avenues of growth for the Canadian hazelnut industry.

Mukund Shukla (mshukla@uoguelph.ca)

S92. Transcriptomic analysis of the response of Brassica napus to Plasmodiophora brassicae
*
Zhou, Q. ; Galindo-González, L.; S-F. Hwang; S. Strelkov
University of Alberta

Clubroot, caused by the biotrophic parasite Plasmodiophora brassicae Wor., is an important disease of
cruciferous crops worldwide. To improve understanding of the mechanisms of resistance and
pathogenesis in the clubroot pathosystem, the transcriptomes of two rutabagas (Brassica napus var.
napobrassica (L.) Rchb.) were compared by RNAseq analysis. We challenged the cultivars
‘Wilhemsburger’ (partially resistant) and ‘Laurentian’ (susceptible), with P. brassicae pathotype 3A, and
harvested roots at 7, 14 and 21 days after inoculation (dai). Microscopy preparations showed reduced
colonization of the host roots for ‘Wilhemsburger’ relative to ‘Laurentian’. Differentially expressed genes
(DEGs) were identified by comparing inoculated plants with non-inoculated controls. At 7 dai, a greater
number of DEGs was detected in ‘Wilhemsburger’ vs. ‘Laurentian’, with a significant number of genes
showing opposite expression patterns in the two hosts. At this stage, genes associated with ethylene-
related pathways and transcriptional regulation were upregulated in ‘Wilhemsburger’. At 14 dai,
pathways related to the cell cycle and division, as well as organ development, were induced specifically in
‘Laurentian’. However, these pathways were induced in both hosts at 21 dai. Also at 21 dai, some biotic
stress related pathways were still active in ‘Wilhemsburger’ but inactive in ‘Laurentian’. The results
suggest that DEGs involved in early resistance pathways are important in limiting infection, and that
resistance responses are weaker in the susceptible host at later stages of infection.

Qinqin Zhou (qinqin@ualberta.ca)

Page 151 of 339