Page 146 - PC2019 Program & Proceedings

PLANT CANADA 2019

S77. Age of divergence among subgenomes determines gene expression between paralogs in
Camelina species
*1
2
4
4
3
3
Chaudhary, R. ; S. Kagale ; C.S. Koh ; E.E. Higgins ; A.G. Sharpe ; I.A.P. Parkin
1 University of Saskatchewan
2
National Research Council Canada
3
Global Institute for Food Security
Agriculture and Agri-Food Canada
4
Camelina sativa, an oilseed crop, is a hexaploid and based on comparison of its genome structure with
those of its wild relatives was formed through step-wise hybridization events. The subgenomes of C.
sativa have undergone limited changes post-hybridization, irrespective of the age of divergence for these
subgenomes. The underlying subtle variations in the subgenomes are important for subsequent
hybridization success of the crop. This study determined the overall subgenome dominance observed in
Camelina species and identified the relationship between the age of divergence of each subgenome and
the expression pattern among the gene paralogs. A linear relationship between the age of divergence and
the dominance of the subgenomes was discovered. We found the basal subgenome of Camelina had a
lower number of expressed genes compared to an earlier diverged subgenome. The third subgenome
shared by C. sativa, C. alyssum and C. microcarpa that resulted from the oldest divergence event was
found to be dominant in comparison to the other two subgenomes. In contrast, in C. neomicrocarpa, a
hexaploid with one unique subgenome compared to C. sativa, the second subgenome, which showed the
earliest divergence age among the three subgenomes, was again dominant. This suggests irrespective of
the species the subgenome dominance has a relationship with the age of the divergence of the
subgenomes in Camelina species.

Raju Chaudhary (raju.chaudhary@usask.ca)

S78. Transcriptome changes associated with phytoglobin expression during germination of barley
seeds
*1
Zafari, S. ; K.H. Hebelstrup ; A. Igamberdiev 1
2
1 Memorial University of Newfoundland; Aarhus University
2

To understand how the class 1 phytoglobin (Pgb) manages the energy crisis and supports the embryo
growth via nitric oxide (NO) metabolism modulation, we performed the analysis of physiological and
molecular parameters in the embryos of transgenic barley (Hordeum vulgare L. cv Golden Promise)
plants differing in expression levels of the Pgb gene (Pgb+ and Pgb–) during germination. The genes
encoding the proteins involved in the Pgb-NO cycle (Pgb, nitrate reductase) and S-nitrosoglutathione
reductase (GSNOR) were highly expressed to control the level of NO and generate growth potential in the
Pgb+ embryos. Lactate and alcoholic fermentation were activated in all tested samples, but more
significantly in Pgb– embryos, which indicated that lactate and alcohol dehydrogenase are involved in the
anaerobic step of germination more actively when Pgb is underexpressed. The up-regulation of genes
encoding the fermentative enzymes contributed to a higher ratio of ATP/ADP in the anaerobic step of
germination. The overexpression of succinate dehydrogenase and pyruvate dehydrogenase in Pgb+
embryos after radicle protrusion highlighted a substantial role of the Pgb-NO cycle in enhancing TCA for
provision of metabolic intermediates and ATP during germination. These results offer an invaluable
picture of how the efficient Pgb-NO cycle affects the dynamic gene expression and protein turnover for
the maintenance of redox and energy balance in germinating seeds.

Somaieh Zafari (szafari@mun.ca)

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