Page 166 - Plant Canada 2024 Proceeding

PLANT CANADA 2024

phenotype genome-wide association studies, the genetic architecture for each trait was uncovered, and
the associated genes and single nucleotide polymorphic (SNP) markers identified. The reported data
suggest that the identified potato clones can be used as climate adaptation solutions for short and long
growing season agrosystems and the SNP markers used for breeding maturity and drought tolerance
traits in potatoes.

[O126] GENOMIC DISSECTION OF ISLAND SYNGAMEONS: ARBORESCENT ASTERACEAE FROM
2
1
1
ST HELENA (SOUTH ATLANTIC OCEAN). Quentin Cronk , Andreas Kolter , and Mikko Paajanen .
1 Department of Botany and Beaty Biodiversity Museum, University of British Columbia, Vancouver, BC,
2
Canada V6T 1Z4; and Centre for Biodiversity Genomics, University of Guelph, 50 Stone Road East,
Guelph, ON, N1G 2W1
Correspondence to: quentin.cronk@ubc.ca

The genera Commidendrum (4 spp.) and Melanodendron (1 sp.) from St Helena (South Atlantic Ocean)
form a single clade whose ancestor reached the island in the early Pliocene. All species have highly
divergent morphologies linked to ecology. Commidendrum and Melanodendron are known to form an
intergeneric hybrid and Commidendrum is known to form interspecific hybrids. Plant genomics can
untangle complex histories of hybridization on islands. Genomic evidence is presented that hybridization
has occurred in the Commidendrum/Melanodendron clade due to recent conservation efforts due to
planting species in proximity. Furthermore, there is genomic evidence that hybridization events may be
ancient, with the species forming a syngameon, so raising the genetic effective population sizes (Ne) of
species. A syngameon is here defined as: “a group of otherwise distinct species interconnected by limited
gene exchange, i.e. the most inclusive interbreeding evolutionary unit” (Suarez-Gonzalez et al., "Adaptive
introgression: a plant perspective" Biology Letters 2017). Such hybridization events are postulated to be a
continual source of background ‘evolutionary rescue’ of species from any small population size impacts
over geological time, a phenomenon of particular importance and impact on islands. Genomic studies are
an essential tool for the study of plant evolution on islands, and for endemic plant conservation.

[O127] NUTRIENT LIMITATION IN SUBARCTIC TERRESTRIAL PLANT COMMUNITIES. John
Markham and Emily Klapprat. Department of Biological Sciences, University of Manitoba, Winnipeg, MB,
Canada, R3T 2N2
Correspondence to: john.markham@umanitoba.ca

Nutrient limitation is increasingly being recognized as a determinant of community structure of terrestrial
communities in the subarctic. We use fox dens as natural experiments to look at the effect of nutrient
enrichment on plant communities at the subarctic treeline. Our work shows that many tundra plants show
an increase in nutrient content and specific leaf area on fox dens, but there is also a shift in plant
composition, with dens having species that are less reliant on mycorrhizae that can access organic
nitrogen in the soil. We also show that trees at the northern treeline have very poor seed production and
viability, both increasing in trees growing fox dens. This suggests that nutrient-enriched sites could be hot
spots of tree reproduction, treeline expansion and squirrel feeding. While increased soil nutrient
availability can drive changes in plant traits and composition, soil properties are partially driven by plant
properties and species composition. We test this by comparing the fertility of soil under Empetrum
nigrum, Salix planifolia and Vaccinium uliginosum growing in undisturbed woodland and an area that
experienced a severe fire 28 years ago and where vegetation had developed into monospecific patches.
As expected, soil from Salix patches was more fertile, with test plants (Elymus molis) having twice the
growth rate in this soil type. Soil from Salix patches also had twice the concentration of inorganic N and in
the burn site, a higher pH, but there was no difference in the depth of the organic layer, rate of soil
respiration, or the soil water holding capacity. These results suggest that in the subarctic climate plant
species can have an effect on soil fertility.

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