Title of the PhD thesis
Genetic and epigenetic regulation of freezing tolerance in woodland strawberry (Fragaria vesca)
Main research findings
Frost damage is a major challenge to perennial crops like strawberries. The duration and intensity of cold winters can destroy plants, leading to economic losses for farmers and reduced availability for consumers. This PhD thesis employed genetics and epigenetics methods to investigate why some strawberry plants survive severe frost, and others do not, a question especially relevant for Nordic agriculture.
Three ecotypes of woodland strawberry (Fragaria vesca) were used in this thesis: ‘Alta,’ ‘NCGR1363,’ and ‘FDP817.’ An initial study found that the magnitude and duration of the expression of known cold-responsive genes through a culmination of transcriptional and post-transcriptional mechanisms was associated with enhanced cold hardiness in 'Alta', the most cold-tolerant genotype characterized.
The second stage of the study identified a genomic region controlling freezing tolerance in F2 progeny from a cross between ‘Alta’ and the moderately cold-tolerant ‘NCGR1363’ ecotype. Within this region, novel candidate genes as well as genes previously linked to cold survival were found to be differentially expressed in response to cold.
Finally, a global characterization of differential DNA methylation and gene expression in response to cold found that ‘Alta’ exhibited both the greatest diversity in differential transcript accumulation and epigenetic plasticity as measured by DNA methylation in response to cold stress compared with ‘NCGR1363’ and ‘FDP817,’ the least cold-tolerant ecotype in the study.
Overall, this work increases understanding of cold acclimation in strawberries. It also identified genetic components and epigenetic modifications that could be developed into molecular markers to assist in breeding octoploid strawberry varieties better adapted to increasingly unpredictable winters in the Nordic region and other temperate regions.
Trial lecture
The candidate will first give a trial lecture on the following topic:
To what extent can epigenetic variation contribute to plant adaptation and crop improvement in a changing climate?
Adjudication committee
- Principal Investigator / Research Director Etienne Bucher, Agroscope, Switzerland
- Research Professor Anita Sønsteby, NIBIO, Norway
- Professor Pål Falnes, Department of Biosciences, University of Oslo, Norway
Chair of the defense
- Professor Rein Aasland, Department of Biosciences (IBV), University of Oslo, Norway
Supervisors
- Professor Paul Eivind Grini, Department of Biosciences (IBV), University of Oslo, Norway
- Professor Robert C. Wilson, Department of Biotechnology, University of Inland Norway
- Professor Wenche Johansen, Department of Biotechnology, University of inland Norway
- Head of Research and Development Muath Alsheikh, Graminor AS, Norway