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Hur försvarar sig växter mot insekter?/How do plants defend themselves against insects?
Johan Meijer
En växt utsätts för många olika stressmoment under sin livscykel, t.ex. patogener och skadeinsekter. Eftersom växter är stationära så kan de inte undvika sina fiender utan har istället utvecklat olika mekanismer för att försvara sig mot angrepp. Vi studerar den naturliga variation inom försvar, primärt myrosinas-glukosinolat systemet, som olika kål-/senaps-växter (Brassicas) uppvisar vid insektsangrepp. Du kommer att screena genetiskt olika varianter av Arabidopsis thaliana för känslighet mot insektslarver. De mest känsliga/resistenta typerna kommer sedan att karakteriseras ytterligare. Tekniker som kan komma att användas inom projektet är bl.a. bio-imaging, qPCR, uttryck av reportergener, uttryck av rekombinanta proteiner i Pichia pastoris, proteinrening och Western blot. Studien kommer att ge oss ny information om hur resistens mot insekter har utvecklats och hur vi kan förbättra växtskydd.
Plants encounter a variety of abiotic and biotic stresses, e.g. microorganisms and insect pests, during their lifetime. Being sessile organisms they cannot avoid their attackers but have instead developed different defence mechanisms. We investigate the natural genetic variation of the Brassicaceae plant family in insect defence, especially the myrosinase-glucosinolate system. You will screen genetically different types of Arabidopsis thaliana for resistance/susceptibility to insects. Selected variants will be further characterized. In the project a variety of techniques will be used, such as bio-imaging, qPCR, reporter gene expression, recombinant protein expression in Pichia pastoris, protein purification and Western blot. The study will provide us with new insights on how insect resistance has evolved and how we can improve plant protection.
Finemapping of QTL in Salix genomes
Sofia Berlin Kolm and Anki Rönnberg-Wästljung
We work in the SAMBA program (Salix Molecular Breeding Activities) with the general aim of developing molecular markers for marker assisted selection in Salix. Salix is grown as a bioenergy crop and the need for new varieties adapted to different environments is of major importance as the demand is growing. The main focus is on developing molecular markers in QTL (quantitative trait loci) that have been identified for several traits with effects on biomass production. We are focusing on rust and insect resistance, different phenology traits and heat- and water stress tolerance. In some of the QTL, we need to increase the marker density (i.e. finemapping) in order to identify individual genes responsible for the traits of interest. We therefore propose a project where QTL will be finmapped. The first step in such a project is to design primers by the use of the poplar genome and to use these in PCRs with DNA of parents of mapping populations. The successful ones will then be sequenced and analysed for informative SNPs (single nucleotide polymorphisms). When a suitable number of SNPs have been identified we will genotype a number of individuals in our experimental populations. Finally linkage maps will be created. This project is a mix of bioinformatics, lab- and field work.
Programmed cell death in plants
Peter Bozhkov
All nucleated organisms (eukaryotes), from simple fungi to animals and plants, require that certain cells die after fulfilling their function. This death process is well-coordinated and occurs in the right time and place. It is genetically controlled by the organism itself and therefore called programmed cell death (PCD). PCD contributes to the formation of new organs and tissues, and to the elimination of excess and damaged cells. The genes that govern PCD in the animal kingdom are highly conserved, from the tiny worm Caenorhabditis elegans to man, a discovery that was awarded the Nobel Prize in Physiology or Medicine in 2002. However, many of these animal genes have no direct homologs in plants. We therefore lack a clear understanding of how PCD is regulated in plants. We are studying mechanisms of PCD in plants using well-characterised model systems, where PCD is an integral part of plant development. This knowledge is important for the better understanding of the evolution of PCD machinery and for growing plants with improved yield and resistance.
Hur regleras utvecklingen av växtembryon? / How is embryo development regulated in plants?
Sara von Arnold
Tidigt under embryoutvecklingen hos växter anläggs skott- och rotanlag. Från dessa anlag utvecklas hela plantan/trädet. Vi kan också stimulera vanliga kroppsceller att bilda embryon (somatisk embryogenes). En metod som används för kloning av växter. Inom ramen för detta examensarbete får du studera hur utvecklingen av embryon regleras.
Most morphogenic events in plants occur in the sporophyte following seed germination, however, the embryonic phase is crucial as it is then the meristems and the shoot-root plant body pattern are specified. For correct growth a constant flow of cells through the meristems must be maintained, where the input of dividing pluripotent stem cells offsets the output of differentiating cells. One extra cell division once a year would make the meristem 1000 times larger than normal after 10 years. Within the framework of this exam project you will study the regulation of embryo development in plants.
Evolution of developmental processes in plants – from mosses to higher plants
Eva Sundberg and 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
Eva Sundberg and 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.
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.
Functionalization of Renewable Material for Industrial scale in vitro Propagation
MSc Project at SweTree Technologies AB
SweTree Technologies (www.swetree.com) is a plant and forest biotechnology company providing products and technologies to improve the productivity and performance properties of plants, wood and fiber for forestry, pulp & paper, packaging, hygiene, textile and other fiber related industries. SweTree Technologies has 32 employees in offices and laboratories in Stockholm, Uppsala and Umeå.
The section of SweTree technologies in Uppsala focuses on biotechnology- enhanced propagation of Elite trees. The main effort is to start up the industrial scale in vitro propagation system for Norway spruce. Part of the propagation process requires control of microbial growth in a non-sterile growth environment. In this MSc project, the student will work with the SweTree technologies team of chemists and biologists on developing a novel, functionalized product based on renewable materials that meet the needs for microbial control and developmental support of the spruce propagules.
We are looking for a motivated student that has experience of sterile techniques and/or cell- and tissue culture procedures. Some background knowledge of plant developmental processes is desirable. The project involves various laboratory tasks associated with in vitro propagation, and basic level chemistry procedures. Excellent communication and documentation skills in English are required.
The project can start ASAP from April 2012 at our site located in Uppsala Business Park in Fyrislund Uppsala.
For more information, please email Ulrika Egertsdotter (ulrika.egertsdotter@swetree.com) or Sven-Erik Sköld (sven- erik.skold@swetree.com), or call +46 706 395 013.
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