Page 182 - Plant Canada 2024 Proceeding

PLANT CANADA 2024

relatively simple, reduced morphology. Trees in the genus Populus further separate the production of
male and female organs onto different individuals. This mode of reproduction differs from the mixed
anatomy of bisexual flowers that is observed in plants such as Arabidopsis and allows to tease apart sex-
specific pathways.

Our work provides mechanistic insights into the regulatory mechanisms of sex determination and sex
expression, and it provides valuable information to ensure reproductively healthy forests.

[O153] FORMATION OF A STABLE TUBULAR ER NETWORK REQUIRES A LOCALIZED
PHOSPHATIDYLCHOLINE SYNTHESIS IN ARABIDOPSIS. Weina Wang. McGill University
Correspondence to: weina.wang@mail.mcgill.ca

Phosphatidylcholine (PC) is a major component of phospholipid to constitute bilayers of the endoplasmic
reticulum (ER) membrane. Membrane fusion of different ER tubules driven by RHD3 in Arabidopsis
functions to form and maintain the interconnected ER network, whilst synthesis and rearrangement of
membrane lipid is required to form and remodel the ER during continuous membrane fusion. However, it
is still unclear how the role of PC affects the ER formation and remodeling, especially in the process of
membrane fusion mediated by RHD3. Through forward genetics, a genetic enhancer of rhd3-1 named
ren10 was identified. In this study, the REN10 gene was cloned by map-based cloning, which encodes
phosphorylcholine cytidylyltransferase (CCT1) which is the rate-limiting enzyme in the biosynthesis of PC.
The deletion or mutation of CCT1 leads to short root hairs and aggregated ER network. And CCT1 is
partially localized in the ER and is involved in the regulation of ER formation. The membrane targeting of
CCT1 in ER is reduced in the absence of RHD3 although there is no physical interaction between CCT1
and RHD3. The localized PC synthesis in the ER is reduced in ren10 mutant. We conclude that the
localized PC synthesis is required to form and maintain a tubular ER network.

[O154] TESTING THREE ALTERNATIVE TECHNOLOGIES AGAINST POWDERY AND DOWNY
MILDEWS ON WINE GRAPE, GREENHOUSE CUCUMBER, FIELD ZUCCHINI AND STRAWBERRY.
1
1
1 1
Andrew C. Wylie , Irina Perez-Valdes , and Rose Buitenhuis . Vineland Research and Innovation Centre,
4890 Victoria Avenue North, Box 4000, Vineland Station, ON, Canada, L0R 2E0
Correspondence to: andrew.wylie@vinelandresearch.com

Powdery and downy mildews are perennial diseases that cause economically significant damage across
horticulture. These diseases, caused by a variety of pathogens, are managed with a combination of
strategies including fungicides, to which these organisms develop resistance. Effective and safe
strategies that also manage fungicide resistance continue to be sought. Alternatives to conventional
treatments for mildews need to be carefully tested for efficacy, phytotoxicity, practicality and other
considerations. We were interested in performing field and greenhouse trials to investigate three
alternative controls for mildews: a photodynamic inactivation application (SUN-D-06, Suncor
AgroScience), a hydroxyl radical treatment (Clean Works), and an air purification/enzymatic degradation
reactor process (Clean Air Zone Ag). The photodynamic inactivator treatment was tested in naturally
inoculated field trials on powdery mildew of zucchini (Podosphaera xanthii) where it demonstrated
efficacy. The hydroxyl radical treatment was tested on hoophouse strawberry inoculated with
Podosphaera aphanis. Infections were eliminated but preliminary results were inconclusive. This
treatment was tested at pilot scale on hoophouse-grown grapes inoculated with Erysiphe necator,
demonstrating suppression of powdery mildew, and at commercial scale with natural Erysiphe necator
and Plasmopara viticola infection showing suppression of powdery mildew as well as reduction of downy
mildew. The air capture and enzymatic degradation reactor was tested in greenhouse cucumber
inoculated with Podosphaera xanthii where it reduced powdery mildew disease severity. With efficacy
demonstrated for these three technologies, future efforts are considered including further validation of
these results, calibration of the treatments and engineering applications. The three alternative methods
for suppression of mildews tested show promise for disease suppression and fungicide resistance
management, adding potential management strategies to reduce crop damage from these pests.

181