Page 224 - PC2019 Program & Proceedings

PLANT CANADA 2019

P21. Screening for heat stress resistant genotypes and evaluating heat stress effect on yield in hard
red spring wheat when exposed to heat stress during flowering
*
Abeysingha, D. ; J. Ozga; D. Spaner; D. Reinecke
University of Alberta

The reproductive phase of wheat (Triticum aestivum L.) is highly sensitive to high-temperature stress.
Temperatures above the growth optimum (23 C) interfere negatively with the reproductive development
0
processes, resulting in poor seed set and weight in wheat. The growing season temperatures are predicted
o
to rise in the future by at least 0.2 C per decade, which will affect wheat crop growth and
development. Therefore, we are screening a recombinant inbred (RI) population (173 RI lines) derived
from the cross between parental lines ‘Attila’ and ‘CDC Go’ that vary in their high temperature sensitivity
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with respect to seed yield. High temperature treatment (35 C for 6 hrs for 6 days) was imposed at an
early reproductive growth stage (BBCH 41-45) to the RIL population in a growth chamber environment.
Results from an analysis of variance (ANOVA) found that heat stress significantly reduced the grain
number per spike (by 23%), grain weight per spike (by 20%), plant height (by 6%), and flag leaf width
(by 2%) in the RIL population. A significant interaction between RIL lines and temperature treatment
main effect means for grain number per spike indicates that the RIL population varies in this trait with
respect to temperature at flowering. We will determine if specific gene markers within the RIL population
are associated with heat stress sensitivity on grain yield.

Dhanuja Abeysingha (abeysing@ualberta.ca)

P22. Expression and localization of the Arabidopsis thaliana HOTHEAD protein in response to
stress.
Francom, T. ; S. Lolle
*
University of Waterloo

Plants live in constantly changing, often unpredictable environments and have evolved diverse strategies
to adapt to these changes. The first line of defense for land plants is the cuticle – a layer which covers the
epidermis on above ground organs and serves to protect them from desiccation, irradiation, and
pathogens. In addition to playing a key role in defense, the cuticle mediates organ separation and
expansion. Many genes involved in regulating cuticle formation and function have been identified
through forward genetic screens and one such gene is HOTHEAD (HTH). Plants harboring mutant hth
alleles show ectopic organ fusion, a phenotype resulting from changes in cuticle permeability. Transgenic
plants expressing HTH translationally fused to fluorescent reporter gene constructs fully restore hth
mutants to wild type and show that the HTH protein is associated with the endoplasmic reticulum (ER).
Our studies show that HTH is localized to a specific set of stress inducible ER-derived organelles known
as “ER bodies” and can be isolated from cell fractions enriched for ER bodies. These findings suggest that
HTH plays a role in both cuticle formation and stress responses. To further investigate the role of HTH in
stress response pathways, HTH transcript and protein expression patterns were examined under stress
conditions and were found to respond to both wounding and salt stress.

Therese Francom (tm2francom@uwaterloo.ca)

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