Bourlaye Fofana, Ph.D.

Toward evidence that homologs of RPW8 act through salicylic acid signaling in powdery mildew resistance in flax
Vanessa Clemis1,2, Mohsin Zaidi, Frank You3, Chunfang Zheng3, Sylvie Cloutier3, and Bourlaye Fofana1
1Charlottetown Research and Development Centre, Agriculture and Agri-Food Canada, 440 University Avenue, Charlottetown, Prince Edward Island, C1A 4N6, Canada
2University of Prince Edward Island, 550 University Avenue, Charlottetown, Prince Edward Island, C1A 4P3, Canada
3Ottawa Research and Development Centre, Agriculture and Agri-Food Canada, 960 Carling Avenue, Ottawa, Ontario, K1A 0C6, Canada
*bourlaye.fofana@agr.gc.ca
Powdery mildew (PM) is an obligate biotrophic fungus (Podosphaera lini) causing high yield loss to flax (Linum usitatissimum L.). To date, no PM resistance genes have been fully functionally characterized. Using GWAS, we identified a locus harboring three flax homologs of the Arabidopsis RPW8 genes that confer broad-spectrum resistance to powdery mildew. Here, we characterized the gene expression profile of the three RPW8 candidate genes following PM inoculation. The data showed that, similar to RPW8.2 acting through the salicylic acid (SA) signaling pathway, the RPW8 homologs Lus10000835 and Lus10000836 are highly expressed in resistant flax lines compared to the suscpetible lines. In contrast, the flax RPW8 homolog Lus10009328 was highly expressed in the susceptible lines, suggesting a different signaling pathway from the other two homologs. RPW8.1 has been shown to activate ethylene signaling through aminocyclopropane-1-carboxylate oxidase gene isoform 4 (ACO4) and, this elevated ethylene negatively regulates the expression of RPW8.1, thereby attenuating its mediated-cell death and disease resistance when no disease is present to avoid unnecessary defense responses. We conclude that PM resistance induced by RPW8 in flax may mainly be activated through SA signaling pathways, and perhaps similarly to the ethylene signaling in Arabidopsis.

Flax Genomic Workshop - Workshop organizer

Fighting against potato greening
Louis G. Sebarese LG1, Mohsin Zaidi1, Christian Lacroix2, Fatima Mitterboek3, Benoit Bizimungu3, and Bourlaye Fofana1
1Charlottetown Research and Development Centre, Agriculture and Agri-Food Canada, 440 University Avenue, Charlottetown, Prince Edward Island, C1A 4N6, Canada
2University of Prince Edward Island, 550 University Avenue, Charlottetown, Prince Edward Island, C1A 4P3, Canada
3Fredericton Research and Development Centre, Agriculture and Agri-Food Canada, Fredericton, New Brunswick, E3B 4Z7, Canada
Potato is the largest vegetable crop in Canada, with an export value of $1.8B in 2019. As a major food source, potato nutritional quality and safety are critical for the public health. Potato greening, also known as potato sunburn, causes 2-3% loss at the farm gate and up to 17% during postharvest and retail storage. It results from a de novo synthesis of chlorophyll in the cortical parenchyma cells under the periderm after light exposure and leads to a simultaneous formation of toxic steroidal glycoalkaloids (SGAs). Whereas chlorophyll itself is not a health hazard, SGAs are toxic to humans and animals. Development of potato cultivars that are resistant to light-induced greening is a viable strategy for an economic and environmental sustainability. We will present and discuss our approach and preliminary results towards an understanding of the tuber greening phenomenon in potato.

Potato greening: gaining an understanding through ‘omics approaches
K. Dougherty1, T. F. Mitterboeck1*, M. Lague1, M. Zaidi2, B. Bizimungu1, and B. Fofana2. 1Agriculture and Agri-Food Canada, Fredericton, New Brunswick, Canada E3B 4Z7 (e-mail:fatima.mitterboeck@agr.gc.ca); and 2Agriculture and Agri-Food Canada, Charlottetown, Prince Edward Island, Canada C1A 4N6.

Potato ‘greening’ occurs when tubers are exposed to light, and results from a de novo synthesis of chlorophyll and a simultaneous formation of steroidal glycoalkaloids, which are toxic to humans and animals. Potato is the largest vegetable crop in Canada, and this greening causes substantial loss of products. Currently, there are no potato cultivars that are resistant to light–induced greening available on the market. The goal of this study is to understand the genetic components and molecular mechanisms of light-induced greening, and to use this knowledge to develop gene-editing tools to generate cultivars resistant to greening. From a core germplasm collection of over 800 mutant potato clones, two clones were observed to be tolerant to light-induced greening. These two non-greening clones, along with a greening control, underwent whole genome sequencing as well as transcriptomic sequencing after light exposure. Here, we will show our findings on single nucleotide polymorphisms (SNPs) and structural variants (SV) that differentiate the non-greening from greening clones. Deploying the non-greening trait into popular potato cultivars would be of high interest to the industry and stakeholders both for tuber appearance, quality, safety, marketability, and food waste reduction.

Gene expression study of the flax-powdery mildew interaction

The Search for Powdery Mildew Resistance Genes in Flax

PhD Thesis of Ashok Somalraju - Non disclosure agreement

https://pag.confex.com/pag/xxvii/meetingapp.cgi/Session/5691

https://www.eventscribe.com/2018/ASPB/searchbyposterbucket.asp?pfp=PosterBucket