The Parniske laboratory (www.genetik.biologie.uni-muenchen.de) is situated in the Biocenter of the University of Munich (LMU), Germany. The Biocenter is equipped with state of the art instrumentation to carry out molecular, biochemical and cell biological research, and can be conveniently reached by public transport from the city center of Munich.
please send your application via email to Martin Parniske (email@example.com) withe a referral to this advert ("Positions offered August 2021") in your cover letter.
Ideally, your application includes all materials required for an application at the LSM at LMU (this list applies also to postdoctoral applicants) but at the very least your curriculum vitae, names of two referees, a motivation letter and a qualification statement. The motivation letter must include an explanation why you are interested in this particular project and the content must thus go beyond general non-project related statements like "the LMU is a great university".
Please also explain in a qualification statement on a separate page what makes you particularly qualified to carry out the project you applied for.
If you found this page by searching for a PhD student position, you should apply for one of the doctoral candidate positions we offer, leading to the german degree "Dr. rer. nat." which is at least as good as - but legally not idential to - a "Ph.D.".
Project for a doctoral candidate:
Sequence adaptations in the symbiosis receptor-like kinase (SymRK) enabeling nitrogen-fixing root nodule development
Plant root symbioses with arbuscular mycorrhiza (AM) fungi and nitrogen-fixing bacteria bear huge potential for sustainable agriculture by reducing the chemical fertilizer input required to maintain high crop yields. The regulation and signal transduction mechanism leading to AM and the nitrogen-fixing root nodule symbiosis (RNS) share a genetic toolkit largely conserved across land plants. It contains a set of signal transduction components including the Symbiosis Receptor-like Kinase SymRK. During evolution, SymRK appears to have acquired novel molecular features that facilitated the development of the nitrogen-fixing root nodule symbiosis, while maintaining its conserved function for AM. In this project, we will explore sequence diversity among SymRK orthologs and paralogs with the goal to narrow down and identify critical sequence adaptations that underlie the rhizobial infection of plant cells. The doctoral student will investigate the mechanistic consequences of these adaptations at the cell biological and biochemical level with a focus on interacting proteins. The relevance of SYMRK paralogs and interacting proteins will be explored by reverse genetics utilizing transposon insertion populations or CRISPR/CAS genome editing technology and quantitative binding studies in vivo using advanced light microscopy and in vitro using a range of state-of-the-art technologies. We expect novel insights into the molecular mechanisms facilitating the symbiotic infection process of plant cells by nitrogen fixing bacteria.
Project for a postdoc or doctoral candidate:
The impact of plant antibiotic metabolites and bacterial multidrug resistance genes on the root microbiota composition
Plant species differ widely in the chemical spectrum of phytochemicals with antimicrobial properties (“antibiotics”) they produce. This may be one of the reasons, why soil bacteria are a major reservoir of antibiotic resistance genes. This project aims to explore to what extend such resistance genes contribute to bacterial survival and competitiveness in and on toxin-producing roots. To this end, we will identify a) toxic compounds from root exudates and b) bacterial resistance genes that protect against these in collaboration with experts in a) plant metabolite analysis and chemistry (Corinna Dawid, TUM) and b) microbiome analysis (Michael Schloter, HMGU). To determine the impact of specific compounds with antibiotic activity on the root microbiome composition, the project will, among other tools, employ plant mutants defective for their biosynthesis. On the bacterial side, we will study the contribution of bacterial multidrug resistance (MDR) genes to increased resistance against specific plant-derived toxins and thus to successful root colonization and competition with other microbiota. We aim to determine whether specific antibiotic compounds within the host root exudate in combination with cognate rhizobial antibiotic resistance genes contributes to the host specificity of the legume-rhizobium symbiosis. The knowledge gained in this project will help informed selection of plant beneficial bacterial inoculants for sustainable agricultural practises.
Spatio-temporal dynamics in the composition and function of the CCaMK/CYCLOPS complex
Plant root symbioses with arbuscular mycorrhiza (AM) fungi and nitrogen-fixing bacteria bear huge potential for sustainable agriculture by reducing the chemical fertilizer input required to maintain high crop yields. The regulation and signal transduction mechanism leading to AM and the nitrogen-fixing root nodule symbiosis (RNS) share common components including the calcium and calmodulin dependent protein kinase (CCaMK) and its phosphorylation target CYCLOPS, a DNA binding transcriptional activator (Tirichine et al., 2006; Yano et al., 2008; Singh et al., 2014). The CCaMK/CYCLOPS complex is a central regulatory hub in symbiosis signaling. It controls the expression of three transcriptional regulators of three distinct developmental programs. NIN controls nodule organogenesis and, together with ERN1, infection thread formation while RAM1 is indispensable for arbuscule development (Singh et al., 2014; Pimprikar et al., 2016; Cerri et al., 2017). The corresponding promoters control distinct timing, expression domains and response to different stimuli. The promoter choice and activity of CCaMK/CYCLOPS must therefore be coordinated at a spatio-temporal and a stimulus-specific level to trigger appropriate cell developmental programs. In the past, we identified additional putative complex components that may contribute to binding of diverse cis regulatory elements within the known target promoters of CCaMK/CYCLOPS. We will study the relevance of the identified additional complex components using a range of techniques, including reverse genetics utilizing transposon insertion populations or CRISPR/CAS genome editing technology. The spatio-temporal composition of the complex and its structural rearrangement will be studied via in vivo FRET-FLIM in root hair nuclei in response to signals emanating from arbuscular mycorrhiza fungi or nitrogen-fixing bacteria. Biochemical in vitro measurements will be used to quantify protein-protein and protein-DNA binding affinities. We expect to unravel key steps in the molecular dynamics of the CCaMK/CYCLOPS complex underlying the specific activation of the appropriate and distinct developmental programs in response to fungi and bacteria and thus the establishment of AM and root nodule symbioses. Further details can be found here