Page 25 - CSHS 2022 Book of Abstracts - 2022-08-22 web version

CSHS 2022 Conference

Abstracts – Poster Presentations

(FP.1) Pool-seq GWAS of ripening, softening and phenolics in apples [presentation withdrawn]
Thomas Davies*, Tayab Soomro, Sean Myles
Faculty of Agriculture, Dalhousie University, Bible Hill, NS
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Harvest date, softening, and phenolic content are important traits in apple fruit. Identifying causal alleles controlling
these traits not only improves the efficiency of traditional breeding programs, but is an essential step for the
application of gene editing technologies. We examined allele frequency differences between groups of
phenotypically extreme individuals from Canada’s Apple Biodiversity Collection using pooled whole genome
sequencing (pool-seq). For each phenotype, we identified >20 million variants and curated candidate genes within
20kb of the variants with the 0.001% most extreme allele frequency differences between pools. We identified loci on
chromosomes 3 and 4 associated with harvest date, the former containing a ripening related transcription factor
NAC18.1. We identified regions on chromosomes 17 and 10 associated with softening. Further, we identified loci on
chromosomes 8 and 16 associated with phenolic content, and suggest a UDP-Glycosyltransferase family gene as a
candidate for phenolic content production. Finally, we list the potential candidate genes in the regions most
associated with each trait.

(FP.2) In vitro elimination of raspberry viruses using thermotherapy, chemotherapy, cryotherapy
and their combination
Véronique Plante 1,2* , Allison K. Walker , Beatrice Amyotte , Shawkat Ali
2
1
1
1. AAFC, Kentville, NS; 2. Department of Biology, Acadia University, Wolfville, NS
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The Pacific Northwest (PNW), which includes the province of British Columbia (Canada) and the states of Oregon
and Washington (United States), is one of the leading producers of red raspberries (Rubus idaeus) in the world. The
PNW raspberry industry is served by the British Columbia berry breeding program based out of the Agassiz
Research and Development Centre of Agriculture and Agri-Food Canada. A total of 161 germplasms from the
breeding program required remediation from infection with Rubus Yellow Net Virus (RYNV), Raspberry Leaf Mottle
Virus (RLMV) and Raspberry Latent Virus (RpLV), which are vectored by the large raspberry aphid, Amphorophora
agathonica. To complete this remediation, in vitro raspberry cultures were subjected to shoot tip dissection
followed by thermotherapy, chemotherapy, cryotherapy or their combination, then a second meristem dissection
post treatment. The meristems were transferred onto different media until they were fully regenerated and
produced roots, from there the plants were transferred to soil. Leaf extracts were collected after 3 and 6 months in
the greenhouse. Virus screening was done using an RT-qPCR on crude extracts. Results suggest that raspberry
plants infected with a single virus become virus-free after shoot tip and meristem dissection only. However plants
infected with a combination of the RYNV and a second virus are still virus-positive after going through all three
treatments. This suggests that there could be a synergic interaction between virus combinations.

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