Plants have evolved numerous ways to escape damage by antagonists. With changing growing conditions, mainly caused by invasive species and effects of global warming, our natural habitats may be increasingly challenged. I am interested in all aspects of plant resistance that may help us under- stand how the risk of biotic stress may be reduced, including chemical and mechanical defence traits, tolerance, phenology displacement and ecological interactions that rescue plants from attack by antagonists. Currently, in my lab, we concentrate 
on studies of Populus tremula, Salix spp., and Brassica nigra.

Benedicte Albrectsen 1150 
Trait association studies and large-scale patterns in Populus
We relate a number of phenotypic traits measured on aspen (Populus tremula) genotypes in the field to assess heritability and resistance to herbivores and pathogens. The biobanks SwAsp (116 clones) and UmeAsp (450 clones) are important for these studies. Since 2004, biotic and abiotic damage to the SwAsp collection has been followed in the field in a G by E setup. We ask if geographical origin matters for resistance properties. Extreme clones (with intensive growth, early bud set, heavy damage by certain antagonists etc.) have been identified for later experimentation in bioassays. We also perform network analyses to understand the arthropod associated communities of our aspen genotypes and chemotypes.

Chemical profiling
We profile the metabolome in Populus, Salix and Brassica especially targeting natural products that may shape resistance to biotic stress. We are interested in the genetics of chemotypes within populations of aspen and between Salix species that display differences in resistance properties against arthropod herbivores and various micro-fungi. We are also interested in getting an organismal perspective on allocation responses in plants in response to various stresses including volatile emissions and induction of various metabolic pools. We use GC/MS to evaluate volatile emissions and general chemical profiles and LC/MS for profiling of specialized natural products (mainly phenolics and glucosinolates).

Studies on induced responses in aspen
We challenge genotypes that display extreme phenotypes by introducing antagonists in whole plant assays or on detached leaves. In aspen, we have for example worked with the aphid Quitophorous populetii the Chrysomela beetles, and the disease Melampsora magnusiana. The aim with these studies is to compare genotypic specific responses in the metabolome to different types of damage, and to test theories on resource allocation to growth and defence.
We have cultured the leaf beetle Chrysomela tremulae and three aphid species of the Quitophorous genus to perform these bioassays. We use choice and no-choice tests to describe preferences and performance of the insects when fed on extreme genotypes under various treatments.

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Some typical arthropods encountered in our common gardens: 1. Harmandia tremula a leaf-galling mite, 2. Bycticus sp. a leaf rolling weevil, 3. Chrysomela populi a leaf beetle that oviposits and chews on leaves, 4. Phyllocnistis labyrintella a leaf mining butterfly.

Volatile Collection Platform
benedicte_5Primary and secondary chemical compounds are extracted from aspen leaves to assess their value as feeding attractants and repellents. We use simple colorimetric analyses as well as advanced mass spectrometric separation techniques to study compounds of interest.
To study volatile responses to biotic stress and simulated stresses (MeJA, and mechanical damaged plants) we have established a volatile collection platform.This platform is created primary for studies of volatile emission in Brassica nigra, however, it is designed to also be used for other plant species.

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