Exam jobs

Evolution of developmental processes in plants – from mosses to higher plants
Mattias Thelander 

We are studying basic fundamental processes in the moss Physcomitrella patens and by using knock-out technology and overexpression studies we answer the following questions:

• Are the same genetic frameworks used for hormonal control in higher and lower plants?
• What is the ancestral function of the plant hormones auxin and cytokinin?
• Do the hormones control analogous developmental processes in higher and lower plants?
• Are higher plant-specific inventions, such as meristems and vascular systems related by descent to seemingly analogous functions in moss?

Genetic and hormonal regulation of fruit development
Jens Sundström

Although a large number of genes regulating fruit development have been discovered, there are still significant gaps in our understanding of the coordinated development of differentiated fruit tissues. We aim at elucidating some of the fruit regulatory networks, with specific emphasis on positioning potential coordinators, such as the plant hormone auxin in the networks. We will screen from interacting partners to known fruit regulators and look for upstream transcription factors using ChIP in inducible systems.

Beneficial plant-microbe interactions
Johan Meijer

Plants are exposed to various forms of stress that hamper growth and yield. We are exploring beneficial bacteria to support growth and improve stress management of plants. These bacteria seem to stimulate the plant through growth promotion as well as priming of induced systemic resistance (ISR) and induced systemic tolerance (IST) to biotic and abiotic stress, respectively. We are using Bacillus amyloliquefasciens strains and interested in mechanisms of plant colonization, growth promotion, priming and stress tolerance in order to support durable plant protection and replace chemical fertilizers and pesticides. Plant root exudates shape the rhizosphere microbiota and it is of interest to identify compounds involved. Analysis of genotype variation is one tool to identify candidate genes for further studies. Another aspect is how plants can differentiate between beneficial and pathogenic bacteria. Functional genomics is used to define the role of various metabolites and genes in this system. The exam project will address various aspects of beneficial plant-microbe interactions.

Molecular epidemiology of plant-infecting viruses
Anders Kvarnheden

Viruses are important pathogens on many crops, and they are also common in natural plant populations. Using molecular tools, we study the molecular epidemiology of plant viruses. The aim is to determine the genetic diversity of selected plant viruses, and to find the factors influencing the composition of virus populations and host specificity. Our projects focus on geminiviruses, which are emerging as serious plant pathogens worldwide, and viruses of importance for Swedish agriculture. The crops we work with include wheat, oats, potato, sugar beet, tomato, okra and cotton. An exam project can also be carried out as a Minor Field Study (MFS) in a developing country or in collaboration with a company/authority.

Varför blir potatisknölar giftiga ibland? /  Why do potato tubers sometimes become toxic?
Folke Sitbon

Potatis innehåller låga halter av giftiga ämnen som kallas glykoalkaloider. Glykoalkaloider finns i hela växten, och halterna är särskilt höga i frökapslar och unga skott. I vanliga fall utgör halten av glykoalkaloider inte något problem för att utnyttja potatisknölen som föda. Men olika former av stress, tex. ljus och skada, kan öka glykoalkaloidhalten avsevärt och göra knölen olämplig eller farlig att äta. Man vet idag ganska litet om hur glykoalkaloiderna bildas, men steroler anses vara troliga förstadium. Inom projektet vill vi med molekylärgenetiska och biokemiska metoder förklara bl.a. hur steroler och glykoalkaloider bildas, vilka gener som samspelar, och varför olika potatissorter varierar i sin stresskänslighet. Vi söker här en examensarbetare som kan hjälpa oss en bit på vägen. 

Potato contains low levels of toxic substances, the glycoalkaloids. The glycoalkaloid level in tubers is normally low, but certain post-harvest stresses, such as light exposure and wounding, can increase levels significantly. Such stresses may render tubers usuitable, or even dangerous, for consumption. The biosynthesis of glycoalkaloids is largely unknown, but sterols are considered as main precursors. The project combines methods within molecular biology and biochemistry to explain how sterols and glycoalkaloids are made, the genes that are important, and why potato cultivars differ in their stress sensitivity. We are here looking for a student who can help us along this way.