In the proposed research I aim to explore the secondary metabolome of the newly identified fungal endophyte Cyanodermella asteris. In this regard, we have selected two in silico-predicted polyketide synthase gene clusters, which will be further examined. The selected gene clusters thereof are chosen for vector construction in Escherichia coli and subsequently the heterologous expression in fungal hosts (Aspergillus niger or Aspergillus nidulans) will be performed. Afterwards, the engineered expression strains will be examined in a combined effort applying mass spectrometry and nuclear magnetic resonance experiments to identify the newly produced compounds. Additional metabolomics-based tools and molecular networking will be employed. Moreover, the biosynthetic pathways of the isolated natural products of the respective gene clusters will be fully delineated.

Diatoms are a large group of unicellular, eukaryotic microalgae that biosynthesize SiO2 (silica)-based cell walls (frustules). They are ubiquitously present in aquatic habitats and key primary producers in the oceans, contributing 20% of the annual photosynthetic CO2 fixation on earth. The architectures of frustules are species specific, displaying intricate patterns of nano- and microscale features, and are believed to be of prime importance for the ecological success of diatoms. Furthermore, in biomineralization research, diatoms serve as model systems to reveal the mechanisms by which organisms are able to generate inorganic materials with complex architectures. Such insight holds the promise of gaining advanced capabilities to synthesize minerals with tailored properties using an environmentally benign processes. During the past two decades, numerous candidate proteins potentially involved in diatom silica biogenesis have been put forward, but only a small number of these have been confirmed to be required for this process. The DiaMorphy project aims to identify the complete set of proteins required for silica morphogenesis in the model diatom Thalassiosira pseudonana. To achieve this, the project will inverse the conventional approach by analyzing silica biogenesis in induced morphological mutants of T. pseudonana rather than in the wild-type. For the first time, single-cell transcriptomics will be applied to study gene expression at specific stages during silica biogenesis. Comparative analysis of the resulting, highly refined transcriptomics datasets, is expected to 'crystallize' a comprehensive core set of silica morphogenesis genes. In proof-of-principle experiments, selected proteins from this core set, will then be functionally characterized in vivo using state-of-the art genetic engineering techniques.