Graduate Students Mini Symposium V - 2026

13:15 h Agnieszka Nurek - AG Bode
Studying regulation of natural products biosynthesis in Xenorhabdus doucetiae by the CRP transcription factor

Bacteria of the genus Xenorhabdus live in symbiosis with Steinernema nematodes and produce diverse natural products with signaling, antibiotic, and insecticidal activities. While many biosynthetic pathways have been identified, the regulatory mechanisms controlling their production remain incompletely understood. It was previously described in our lab that small RNA ArcZ plays important role in regulation of natural products. In my presentation, I will discuss the role of global transcriptional factor CRP in regulating secondary metabolism in X. doucetiae and how it connects to ArcZ-dependent regulation pathway.

13:45 h Grgo Marijan - ENG Rebelein
Nitrogen fixation by diazotrophic bacteria of the leaf microbiota

My study combines two projects on terrestrial nitrogen fixation. First, we analyse diazotrophs in the oak phyllosphere, detecting essential metals (Fe, Mo, V) and nifH genes, yet no significant acetylene reduction. Functional nitrogenase activity was confirmed in Rhodobacter capsulatus expressing a novel Mo-nitrogenase from Yersinia. Second, we determine the minimum Mo concentration triggering the switch from Fe- to Mo-nitrogenase in R. capsulatus under nanomolar Mo, using acetylene reduction, protein expression, and isotopic fractionation. Together, these projects reveal nitrogen fixation potential in temperate plant microbiomes and Mo-dependent regulation in terrestrial diazotrophs.