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TOLs, Regulierer bei abiotischen Stressreaktionen

Korbei Barbara, Projektleiter/in
Art der Forschung
Beteiligte BOKU-Organisationseinheiten
Institut für Molekulare Pflanzenbiologie
Gefördert durch
Fonds zur Förderung der wissenschaftlichen Forschung (FWF) , Sensengasse 1, 1090 Wien, Österreich
Wider research context / theoretical framework
Climate change and its effects on the adaptability of plants to withstand longer drought periods is a highly topical research field. This project deals with the cellular response of higher plants to drought stress, with a special focus on the downregulation of PM associated key components of the absisic acid (ABA) signaling machinery. We intend to functionally characterize the involvement of the TOL (TOM1-like) protein family in degradative sorting of important ABA signaling components via the vacuolar pathway and the involvement of potential trans acting factors, like E3 ligases capable of the formation of K63-linked poly-ubiquitin chains. TOLs functions in the initial steps of ESCRT (Endosomal Sorting Complex Required for Transport)- dependent protein degradation and are thought to be responsible for initiating the pathway for guiding
ubiquitinated PM proteins to the vacuole for their degradation.

Hypotheses/research questions /objectives
Recently a role for the ESCRT pathway in ABA signaling has been described and higher order tol mutant plant line, which resembles a wild type plant line of the same ecotype under standard conditions, is hypersensitive to the plant hormone ABA. In the next 3 years we intend to assess the crosstalk between the TOLs genes and the ABA signaling pathway.

To link the function of TOL genes to the regulation of ABA responses we will assess genetic interaction of the TOLs with ABA-biosynthesis and signaling mutants. Subunits of the ESCRT complex involved in endosomal degradation of ABA receptors will be analyzed for interaction with the TOLs to reveal functional links. ABA transporters and receptors as well as TOL-reporter lines will be assessed with respect to their localization and abundance in different tol mutant backgrounds under drought stress or ABA signaling. The role of TOLs in the downregulation of ABA transporters and ABA receptors will be analyzes as well as indepth systematic localization study of all TOLs. Potential trans acting determinants affecting the role of TOLs in the ABA pathway will include the analysis of an E3 Ligase family capable of catalyzing K63 polyubiquitin chains. Thus, this project will elucidate how the TOL proteins, as initial components of the ESCRT machinery, function in modulating ABA signaling in plants.

Level of originality/innovation
In summary, this project will help to allow us to understand how TOLs, next to their general role in the endosomal degradation pathway, play a more differentiated role in diverse signaling pathways, allowing plants to fine-tune their responses. It will contribute to the question of how plants manage to adapt to their ever-changing environment, with a special focus on drought tolerance.

Primary researchers involved
This project will be used to fund two PhD students for three years each as well as a technician, who will mainly be responsible for the extensive plant work.

Genetik; Molekularbiologie; Zellbiologie (301114);
ABA Signaltransduktionsweg; Arabidopsis thaliana; Endosomaler Pathway; ESCRT; Ubiquitin ;
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