Page 157 - Plant Canada 2024 Proceeding

PLANT CANADA 2024

*[O109] IDENTIFICATION OF QUANTITATIVE TRAIT LOCI (QTL) FOR ERUCIC ACID CONTENT IN
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BRASSICA NAPUS L. Yong Liu , Genyi Li , Harmeet S. Chawla , Robert W. Duncan , and Curt
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McCartney . Department of Plant Science, University of Manitoba, 66 Dafoe Road, Winnipeg, MB, R3T
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Correspondence to: rob.duncan@umanitoba.ca

Brassica napus L., commonly known as canola or rapeseed, is an economically significant crop due to its
high oil content and quality. Erucic acid (C22:1 ω-9) is a long-chain monounsaturated fatty acid, which is
a major component of B. napus oil and plays a crucial role in determining its nutritional and industrial
properties. Erucic acid is used in a wide range of industrial applications, often as a highly effective
industrial lubricant, and is in high demand as a raw material in modern manufacturing. The objective of
this research was to identify and analyze the quantitative trait loci (QTL) responsible for high levels of
erucic acid in B. napus. Two doubled haploid (DH) populations were generated from parental genotypes
with contrasting erucic acid content. The two DH populations (CBER1 and CBER2) consisted of 183 and
182 individuals, respectively. The populations were compared in randomized complete block designs
(RCBD) in two locations in 2020, 2021 and 2022 and fatty acid analyses were conducted using gas
chromatography. DNA samples were extracted from the leaf tissues of the population individuals, and
genotyping was performed using genotyping by sequencing (GBS). Genetic maps were produced from
the detected SNPs and InDels. An inclusive composite interval QTL mapping (ICIM) approach was
employed to detect significant QTL with high statistical confidence. Multiple QTL associated with erucic
acid content were detected across multiple site-years. These QTL were distributed across different
chromosomes, indicating the polygenic nature of erucic acid regulation. In this study, 7 and 5 QTL were
found in CBER2 and CBLD2 populations, respectively. Among them, the QTL found on the A04
chromosome of the CBLD2 population reached a maximum variation of 27%. Minor QTL were also shown
on chromosomes A07, C01, C05 and C02. The identified QTL provide valuable insight into the genetic
basis of erucic acid high quantity trait in B. napus. These findings can facilitate marker-assisted selection
(MAS) programs aimed at developing B. napus genotypes with increased erucic acid content.
Furthermore, the identified QTL can serve as targets for future functional studies, enabling a deeper
understanding of the molecular mechanisms involved in erucic acid biosynthesis and metabolism.

*[O110] TOC159 RECEPTORS: THE ROLE OF PLASTID MEMBRANE GALACTOLIPIDS IN
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TARGETING TO THE CHLOROPLAST OUTER ENVELOPE. Michael Fish , George Saudan , Simon
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Chuong , Masoud Jelokhani-Niaraki , and Matthew Smith . Department of Biology, Wilfrid Laurier
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University, 75 University Avenue West, Waterloo, ON, Canada, N2L 3C5; Department of Chemistry &
Biochemistry, Wilfrid Laurier University, 75 University Avenue West, Waterloo, ON, Canada, N2L 3C5; and
3 Department of Biology, University of Waterloo, 200 University Avenue West, Waterloo, ON, Canada, N2L
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Correspondence to: fish1960@mylaurier.ca

Plastids are a dynamic group of organelles in plant cells that facilitate a variety of functions in different
tissues. They can also transition between types in response to different developmental and environmental
cues. The most well-studied plastids are the chloroplasts, which house the machinery for photosynthesis.
Chloroplast biogenesis and function rely on the targeting of chloroplast preproteins, where N-terminal
chloroplast transit peptides direct preproteins to the translocon at the outer membrane of the chloroplast
(TOC complex), where they are recognized and imported. Chloroplast preprotein targeting, recognition
and translocation through the chloroplast outer envelope by the TOC complex are well characterized
processes. However, the same processes for many outer envelope proteins remain poorly understood.
TOC159 receptors, key components of the TOC complex, represent one such example. We have shown
previously that TOC159 receptors use a novel targeting signal, composed of a highly conserved bi-partite
sequence at the C-terminus, containing β-signal-like and transit peptide-like motifs. Structural predictions
of the TOC159 receptor membrane domain using AlphaFold2, with far-UV circular dichroism (CD)
spectroscopy of the membrane domain expressed in Escherichia coli and purified from inclusion bodies
suggest a β-barrel membrane anchor in detergent and when reconstituted in liposomes. Green
fluorescent protein targeting experiments in plant cells of Arabidopsis thaliana and Allium cepa using
confocal fluorescence microscopy, cell fractionation and immunoblotting demonstrate that the β-signal-

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