Examensarbeten

Title: Investigating evolution of tolerance to chemical fungicides and biocontrol in Botrytis cinerea

Supervisors: Johan A. Stenberg, Esther Kuper (Esther.Kuper@slu.se) 

Department of Plant Protection Biology, Campus Alnarp, SLU

Unit of Integrated Plant Protection

Brief description: The pathogenic fungus Botrytis cinerea is causing severe losses in the cultivation of many horticultural crops, including strawberries. Management of the disease relies to large extent on the use of chemical fungicides, which can have negative impacts on the environment on non-target organisms. Besides, B. cinerea has the capacity to evolve quickly and fungicide resistant strains can appear after few years of fungicide application in the field. 

An emerging field to replace chemical fungicides is microbial biological control. Here, living beneficial microbes are sprayed on the crop that can compete with and kill the pathogen. It is generally expected that evolution of resistance to those biocontrol microbes will take longer time than evolution to chemical products. 

In this thesis project we want to study the time scale of B. cinerea resistance evolution to chemical and biological products. For that we will use methods in microbiology and molecular biology.

Tasks (these can also be discussed, and new experiments can be added)

1.      Testing fungicide resistance in B. cinerea after 2-4 years of fungicide treatment 

a.      In-vitro screening of mycelial growth

b.     Screening of known resistance genes

c.      Implementing new protocols for screening fungicide resistance e.g. sporulation assays

2.      Testing B. cinerea resistance to biocontrol after 2-4 years of biocontrol treatment 

a.      In-vitro antagonistic assay

b.     Write a script for ImageJ to analyse antagonistic assay computationally

c.      Implementing new protocols for screening biocontrol resistance e.g. culture filtrate assay

3.      Confirming isolate resistance in-planta or on detached fruits

Time frame:

6 months thesis, starting November 2025. Dates can be discussed.

Title: Enhancing pollination precision by honey bees to garden strawberry

Supervisors: Hanna Thosteman (hanna.thosteman@slu.se), Department of Plant Protection, SLU

Paul Egan, Department of Plant Protection, SLU

Brief description: Increasing pollination precision by honey bees to target crops is a major target for agricultural pollination research. Honey bees are generalist pollinators and may show low affinity for certain crops such as pear and strawberry. To mitigate this, farmers typically increase honey bee hive stocking densities, which can have adverse effects on the surrounding natural environment. Our goal is to find solutions where pollinations effectiveness is increased in relation to hive stocking density.

What you will be doing:

You will be working with western honey bees (Apis mellifera), garden strawberry (Fragaria x annanassa) and several strains of beneficial yeasts and yeast-like fungi in an experiment where we aim to increase the visitation rate to strawberry flowers by manipulating honey bee foraging behaviour. 

This project entails:

Maintenance of live honey bee hives (field)
Maintenance of yeast cultivations (laboratory)
Field experiments in Alnarp

Time frame:

The experimental period runs from early summer (May) and throughout the typical flowering period of strawberry (roughly end of June) in 2026. It’s beneficial to enter the project slightly before experiments start, but the exact arrangement is flexible and can be discussed. Suitable for bachelor and master projects. For master projects, we recommend >30 credit theses, but this is not a requirement.

Title: Genetic mapping and phenotypic characterization of Fragaria vesca (wild strawberry)

Supervisors:
Sebastián Arenas (sebastian.arenas@slu.se), ), Department of Plant Protection, Campus Alnarp, SLU
Carolina Diller, ), Department of Plant Protection, Campus Alnarp, SLU

Brief description: Understanding the genetic architecture of agronomic traits in Fragaria vesca is essential for advancing strawberry breeding programs. In this project, we will combine phenotyping of diverse plant material, statistics analysis with DNA extraction and preparation for downstream genetic analyses (e.g. GWAS and QTL mapping). By integrating phenotypic and genomic data, we aim to identify genetic variants underlying key adaptive and agronomic traits in this important model crop.

What you will be lerning:

• Bioinformatics
• Statistics (R-language)
• Laboratory work

What you will be doing:

• Phenotypic characterization of Fragaria vesca plants under controlled conditions. 
• Recording morphological and agronomic traits (e.g. flowering time, growth, yield-related traits).
• Laboratory work, including leaf sampling, DNA extraction and quality control. 
• Preparation of samples for sequencing and genotyping. 
• Data entry and organization to support genetic mapping analyses.