Page 142 - PC2019 Program & Proceedings

PLANT CANADA 2019

S69. Global insights into duplicated gene expression and alternative splicing in polyploid Brassica
napus (canola) in response abiotic stress by transcriptome sequencing
Adams, K.
University of British Columbia

Polyploidy has made a major impact on plant genomes and several crop plants are polyploids. There is
considerable interest in characterizing expression of genes duplicated by polyploidy in various polyploid
plants using RNA-sequencing approaches. In this study, we conducted comprehensive transcriptome
analyses of Brassica napus, an allotetraploid derived from B. rapa(AT) and B. oleracea(CT), by
transcriptome sequencing (RNA-Seq) of strand specific libraries made from plants subjected to drought,
cold, and heat stress treatments. Analyses of 27,360 pairs of homoeologs (genes duplicated by
polyploidy) revealed ATsubgenome biases in gene expression and CTsubgenome biases in the extent of
alternative splicing under all four treatments. For all types of alternative splicing events, significant
negative correlations were found between expression level and alternative splicing frequency. Cold stress
resulted in the greatest changes in gene expression and alternative splicing changes when compared to the
control. Cold-induced alternative splicing changes were more likely to be shared with those generated by
drought than by heat stress. Our results indicate that divergence in gene expression and alternative
splicing patterns among homoeologs may increase the flexibility of polyploids when responding to
multiple abiotic stressors.

Keith Adams (keitha@mail.ubc.ca)

S70. Linking RNA processing and kinase signaling in the Arabidopsis stress response
Mehta, D.
University of Alberta

Protein phosphorylation via protein kinases is the predominant post-translational protein modification in
Eukaryotes, playing a major role in transmitting extracellular signals such as stress perception to the cell
nucleus. Kinase signaling cascades thereby permit the transcriptional and post-transcriptional machinery
of a cell to sense and respond to external stresses. However, recent proteomics studies in Arabidopsis
thaliana in our lab as well as results in other organisms suggest a new mechanism by which protein
kinase-mediated signaling is linked to RNA processing during cellular responses to stress. Using a
combination of mass-spectrometry based proteomics, transcriptomics and biochemistry to study
proteome, phospho-proteome and iso-transcriptome level changes in Arabidopsis cells, we describe how
nuclear RNA processing machinery intersects with protein phosphorylation in the context of abiotic
stress. The results presented aim to both advance our understanding of how plant cells can diversify their
proteomes upon stress-perception and generate new targets for agricultural applications.

Devang Mehta (devangmehta@ualberta.ca)

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