Page 235 - PC2019 Program & Proceedings

PLANT CANADA 2019

P43. Do r2r3-myb transcription factors directly regulate suberin biosynthesis?
*
Garant, T. ; O. Rowland; J. Murmu
Carleton University

Suberin is a lipid heteropolymer that is deposited at plant-environment and tissue-tissue interfaces as a
protective barrier. In the young roots of Arabidopsis thaliana suberin is found in the endodermis, where
suberin prevents uncontrolled transcellular, and possibly apoplastic, movement of water and nutrients to
and from the central vasculature. Controlling the movement of water and nutrients in the roots throughout
development and in response to abiotic stress are vital to plant health. R2R3-MYB transcription factors
(TFs) promote root suberin production constitutively and in response to abiotic stress, but it is unclear if
they directly target suberin biosynthetic genes. The promoters of suberin biosynthetic genes can be
sufficient for expression in the root endodermis. These promoters are rich in potential R2R3-MYB TF
DNA binding motifs and contain many bHLH TF and WRKY TF DNA binding motifs. This suggests that
each R2R3-MYB TF may form a complex with bHLH and WRKY TFs, when regulating suberin
biosynthetic genes. Future work will use yeast-one-hybrid and promoter activation assays to confirm if
R2R3-MYB TFs, and potential interacting partners (bHLH and WRKY TF), directly bind to and activate
the transcription of suberin biosynthetic genes. Determining how suberin is regulated will improve our
understanding of suberin production and how root suberin functions. This knowledge may lead to the
development of hardier crops through improved root suberin content.

Timothy Garant (timgarant@cmail.carleton.ca)

P44. Processing strategies to reduce the level of acrylamide formation in potato chips, and their
influence on reducing sugar and asparagine concentrations
2
1
3
Liyanage, D. ; D. Yevtushenko ; M. Konschuh ; B. Bizimungu ; Z. Lu
1
3
1 University of Lethbridge
2 Alberta Agriculture and Forestry
3 Agriculture and Agri-Food Canada)
Potato chips contribute to the dietary intake of acrylamide, a probable carcinogen in heat-processed foods.
The aim of this study was to determine the effects of frying conditions and additive treatments on the
levels of reducing sugars, asparagine and acrylamide formation in fried potato chips. Three commercial
potato cultivars (Atlantic, Snowden, and Vigor) were tested using different frying time (3, 5, and 7 min)
and temperature (160, 170, 180, and 190°C) conditions. Acrylamide formation in potato chips increased
with the frying time and temperature, and was accompanied by significant losses of reducing sugars and
asparagine. The lowest acrylamide levels were detected in Snowden potato chips. Decreasing the frying
temperature from 190 to 160°C for 7 min mitigated the acrylamide formation in processed potato chips of
Atlantic, Snowden and Vigor by 84%, 67% and 78%, respectively. Acrylamide formation in potato chips
was also examined after blanching potato slices in additive treatments before frying. The highest
reduction (19-59%) was observed in potato samples that were blanched in distilled water. Among other
blanching methods, the presence of 0.1 M glycine significantly reduced the acrylamide formation in
potato chips from cultivars Atlantic and Vigor (by 49% and 27%, respectively), while 1% citric acid
lowered acrylamide level in Atlantic (by 38%), and 1% acetic acid was effective at lowering acrylamide
in Vigor potato chips (by 31%).

Dilumi Liyanage (kekulandala@uleth.ca)

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