PhD Defence Sophie Lambertz – University of Copenhagen

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PhD Defence Sophie Lambertz

PhD Candidate

Sophie Lambertz

Title of PhD Thesis

Identification and characterization of jasmonate transporters: The role of jasmonate efflux in defense and development

Abstract

The presented thesis is a collection of manuscripts dealing with the role of jasmonate transport in defense and development of Arabidopsis thaliana. Jasmonates accumulate within seconds when plant are attacked by herbivores or experience mechanical damage. As signaling molecules they link damage associated signals to appropriate responses in the plant body, by inducing the plant defense systems and adapting growth and development in the plant. Loss of jasmonate biosynthesis leaves the plant almost helpless against a variety of herbivores and necrotrophic-living pathogens.

One of the most popular characteristics of jasmonates is, that they are lowly abundant under normal growth conditions but reach high levels not only at site of the stimulus but also in distal tissue of the plant. This priming effect is essential to prepare the plant for continuous attacks. The systemic accumulation has been the focus of many studies, which proposed that jasmonate is transported over long and short distances to induce defense responses. However, our knowledge of jasmonate transporting elements is marginal.

In this thesis we identify jasmonate efflux proteins (JEFFs) in a functional screen of the Nitate Peptide transporter Family (NPF) in Xenopus laevis oocytes. To investigate if the JEFFs are involved in JA efflux from the site of synthesis to distal cells or organs of plants, we tested their contribution to defense against the herbivore Spodoptora littoralis and the fungi Botrytis cinerea. Wounding assays indicate that the JEFFs are involved in systemic induction of the defense compounds glucosinolates, which may be caused by a JEFF mediated shift of jasmonate precursors to the biological active form of jasmonates. We further show that jasmonate efflux is involved in root growth and responses as well as in ability of plants to regulate leave growth.

Supervisor

Associate Professor Hussam Nour-Eldin, DynaMo Center, University of Copenhagen

Assessment Committee

Markus Geisler, University of Fribourg, Switzerland
Ivan F. Acosta, Max Planck Institute for Plant Breeding Research, Cologne, Germany
Barbara Ann Halkier, PLEN, DynaMo Center, University of Copenhagen (Chair)

Reception

The defence will be followed by a reception at Thorvaldsensvej 40, room H117

Everybody is welcome!