Page 244 - Plant Canada 2024 Proceeding

PLANT CANADA 2024

*[P81] DORMANCY RELEASE AND TRANSCRIPTIONAL REGULATION OF ABSCISIC ACID AND
GIBBERELLIN METABOLISM GENES IN WHEAT SEEDS. Riya Kalota , Pham Anh Tuan , Deepak
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Sharma , Santosh Kumar , and Belay T. Ayele . Department of Plant Science, University of Manitoba,
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Winnipeg, Manitoba, Canada; and Brandon Research and Development Centre, Agriculture and Agri-
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Food Canada, Brandon, Manitoba, Canada
Correspondence to: kalotar@myumanitoba.ca

Seed dormancy is an adaptive trait that influences the occurrence of preharvest sprouting (PHS), which is
the germination of physiologically mature seeds on the spike before harvest. The presence of low
dormancy in wheat seeds can result in PHS, leading to substantial losses in both yield and quality. The
degree of dormancy in seeds is primarily regulated by two hormones, abscisic acid (ABA) and gibberellin
(GA). To gain better insights into the molecular mechanisms regulating seed dormancy in wheat, this
study conducted a comparative targeted transcriptomic analysis of ABA and GA metabolism genes
between dormant and non-dormant (after-ripened) seeds derived from a highly dormant wheat genotype.
After-ripening of the dormant seeds resulted in release of seed dormancy. The study revealed that genes
involved in ABA biosynthesis such as NCED1 and NCED3 were significantly upregulated during
imbibition of dormant seeds relative to the corresponding after-ripened seeds. On the other hand, genes
involved in ABA catabolism such as CYP707A1 and CYP707A3 exhibited downregulation in the dormant
seed samples. Moreover, genes involved in ABA signaling such as SnRK3, SnRK10, and ABI5 exhibited
higher expression levels during imbibition of dormant seeds relative to that found in after-ripened seeds.
In contrast, genes involved in GA biosynthesis such as GA3ox and GA20ox were downregulated in the
dormant seeds. The expression patterns of GA signaling genes including GID1 and GAMYB was not
consistent with the dormancy phenotype, and this might reflect post-transcriptional regulation of these
genes.

*[P82] UNLOCKING NATURE'S PHARMACY: EXPLORING THE HIDDEN POTENTIAL OF
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LESPEDEZA CAPITATA. Puneet Kaur and Mehran Dastmalchi . Department of Plant Science, McGill
University, 21111 Lakeshore Road, Ste-Anne-de-Bellevue, QC, Canada, H9X3V9
Correspondence to: puneet.kaur2@mail.mcgill.ca

The use of plant natural products for medicine, potions, and ointments predates human civilization and
has profoundly influenced our very existence. The indigenous peoples of North America, including the
Comanche, the Meskwaki, and the Pawnee, have made use of the plants from the Lespedeza genus,
notably L. capitata. Significant uses include treating ailments such as rheumatism and neuralgia and as
an antidote for poisoning. Metabolic profiling of Lespedeza spp. over two decades ago showed the
presence of unique and obscure derivatives of the isoflavonoid scaffold. This class of compounds is
associated, physiologically, with signalling to beneficial bacteria and protection against pathogenic
microbes. Furthermore, they have immense potential in pharmacological applications as antioxidants and
reno-protective and tissue regenerative medicines. Despite these promising findings, there is a notable
gap in our understanding of the metabolic pathways and genetic underpinnings involved in the
biosynthesis of these compounds. To fill this knowledge gap, I have undertaken a spatiotemporal
approach to describing the metabolic profile and identifying the corresponding transcripts at various
stages and tissue types of L. capitata. Tissues were harvested from early and mature roots, three stages
of leaf development, stems, and nodules, homogenized and split into two samples: one for RNA and one
for metabolite extraction. RNA isolation was challenging due to the high concentrations of phenolics and
other recalcitrant compounds in the leaf samples, which required lengthy troubleshooting. These samples
have been submitted to Génome Québec for RNA-sequencing using Illumina NovaSeq6000 and will be
subsequently de novo assembled and annotated; followed by differential gene expression analysis to
follow spatiotemporal trends. In parallel, I have used untargeted metabolomics (LC-QTOF/MS) to identify
molecular features (predicted compounds) within these tissues, followed by fragmentation and
comparison to authentic standards to quantify known peaks. This comprehensive transcriptomic-
metabolomic dataset will be probed by a guilt-by-association approach, whereby genes co-expressed
with metabolites, or their intermediates, are presumed to play roles in their biosynthesis, transport, or
storage. Pinpointing these genes will provide an understanding of the complex and unique metabolic
profile of the understudied Lespedeza genus, particularly of the biosynthesis of isoflavonoids.

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