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Early patterning of organ primordia during barley meristem development uncovered by imputation of gene expression at single cell level.

A prototypic ARC that implements all specification standards accordingly

Reversible Burst of Transcriptional Changes during Induction of Crassulacean Acid Metabolism in Talinum triangulare.

Quantification of cell growth is central to any study of photoautotrophic microorganisms. However, cellular self-shading and limited CO2 control in conventional photobioreactors lead to heterogeneous conditions that obscure distinct correlations between the environment and cellular physiology. Here we present a microfluidic cultivation platform that enables precise analysis of cyanobacterial growth with spatio-temporal resolution. Since cyanobacteria are cultivated in monolayers, cellular self-shading does not occur, allowing homogeneous illumination and precise knowledge of the photon-flux density at single-cell resolution. A single chip contains multiple channels, each connected to several hundred growth chambers. In combination with an externally applied light gradient, this setup enables high-throughput multi-parameter analysis in short time. In addition, the multilayered microfluidic design allows continuous perfusion of defined gas mixtures. Transversal CO2 diffusion across the intermediate polydimethylsiloxane membrane results in homogeneous CO2 supply, with a unique exchange-surface to cultivation-volume ratio. Three cyanobacterial model strains were examined under various, static and dynamic environmental conditions. Phase-contrast and chlorophyll fluorescence images were recorded by automated time-lapse microscopy. Deep-learning trained cell segmentation was used to efficiently analyse large image stacks, thereby generating statistically reliable data. Cell division was highly synchronized, and growth was robust under continuous illumination but stopped rapidly upon initiating dark phases. CO2-Limitation, often a limiting factor in photobioreactors, was only observed when the device was operated under reduced CO2 between 50 and 0 ppm. Here we provide comprehensive and precise data on cyanobacterial growth at single-cell resolution, accessible for further growth studies and modeling.

The trace element iron is essential for life, but elevated levels can rapidly cause cellular damage through oxidative stress. Bacteria, like Corynebacterium glutamicum, tightly regulate iron and heme homeostasis via the global regulators DtxR and HrrA. This study provides the first analysis of the genome-wide binding patterns of these two regulators demonstrating significant differences in binding dependent on the tested iron regimes. Overall, we identified 25 new DtxR targets and 210 previously unknown HrrA targets, including genes with crucial roles in central metabolism and DNA repair. Notably, DtxR was shown to link iron metabolism to methionine synthesis, which might be important to protect the cell from oxidative stress. Our findings highlight the interconnected nature of DtxR and HrrA networks and underscore the value of condition-specific analysis to deepen the understanding of how bacteria adapt to environmental changes. 

The iron-containing porphyrin heme is of high interest for the food industry for the production of artificial meat as well as for medical applications, e.g. for anemia treatment. Recently, the biotechnological platform strain Corynebacterium glutamicum has emerged as a promising host for animal-free heme production. Beyond engineering of complex heme biosynthetic pathways, improving heme export offers significant yet untapped potential for enhancing production strains. In this study, a growth-coupled biosensor was designed to impose a selection pressure on the increased expression of the hrtBA operon encoding an ABC-type heme exporter in C. glutamicum. For this purpose, the promoter region PhrtB was replaced with that of the growth-regulating genes pfkA (phosphofructokinase) and aceE (pyruvate dehydrogenase), creating biosensor strains with a selection pressure for hrtBA activation. Resulting sensor strains were used for plate-based selections and for a repetitive batch f(luorescent)ALE using a robotics platform. Genome sequencing of isolated clones featuring increased hrtBA expression revealed three distinct mutational hotspots: (i) chrS, (ii) chrA, and (iii) cydD. Mutations in the genes of the ChrSA two-component system, which regulates hrtBA in response to heme levels, were identified as a promising target to enhance export activity. Furthermore, causal mutations within cydD, encoding an ABC-transporter essential for cytochrome bd oxidase assembly, were confirmed by the construction of a deletion mutant, which showed strongly increased hrtBA expression as well as increased cellular heme levels. These results further support the proposed role of CydDC as a heme transporter. Mutations identified in this study therefore underline the potential of biosensor-based growth coupling and provide promising engineering targets to improve microbial heme production.

Pangenome of Camellia sinensis

A novel biosensor for ferrous iron developed via CoBiSe - A computational method for rapid biosensor design

"QUINOA DIVERSITY- Quinoa Phenotypic and Genotypic Diversity for Yield and Composition"

This ARC is based on the research of Mönchgesang et al. 2016, who performed a metabolite profiling of 19 Arabidopsis thaliana accessions. The natural variability of root metabolic patterns was analyzed between different accessions, with the result that plant-to-plant variability is greater than natural variation between accessions and non-biological variation between experimental batches.