Biology subjects

Heinemann, B.

Publications and source records attributed to Heinemann, B..

6 recordsLinked to original sources

bioRxiv2026

A Neuronally Active Bacterial Siderophore Manipulates Host Behavior and Longevity

Aging populations face a growing burden of neurodegenerative disease and behavioral decline. The microbiota is increasingly implicated in host physiology, highlighting an urgent need to understand how gut microbes modulate brain function and late life health. Here, we develop a high-throughput microbe-host screening platform to systematically dissect how bacterial genes shape organismal behavior. Using the Escherichia coli Keio library of 3,985 distinct non-essential single-gene deletion mutants in combination with Caenorhabditis elegans, we quantitatively profiled 768 behavioral features per bacterial clone and uncovered a coherent module of bacterial genes involved in iron homeostasis that robustly reprogrammed host behavior. Bacterial omics analyses revealed that alterations in iron homeostasis amplify siderophore production in a TCA cycle-dependent manner, and loss of enterobactin biosynthesis abolished the bacteria-induced changes in worm movement. Transcriptional, molecular and functional studies demonstrated that bacterial enterobactin activates host neuromuscular responses to shape both lifespan and healthspan in a manner dependent on the mitochondrial unfolded protein response. Thermal proteome profiling identified mitochondrial glutaryl-CoA dehydrogenase and the electron-transfer flavoproteins A and B as enterobactin-binding targets that control mitochondrial function. Finally, genetic manipulation of neuronal mitochondrial and cytosolic reactive oxygen species via superoxide dismutase and catalase revealed that redox state modulates enterobactin-driven changes in movement and lifespan through the secretin-family GPCR neuropeptide receptor PDFR-1. Together, these findings establish microbial enterobactin as a non-canonical neurotransmitter regulating neuronal mitochondrial function, behavior and aging, defining a gut bacteria-brain axis with broad implications for maintaining late-life health.

animal behavior and cognition↗

bioRxiv2026

Prion-like domains control plastid targeting of PEPSI effectors and PEPSI6-mediated modulation of DXR during root symbiosis

Microbial effectors often act in the apoplast or cytosol, but how they reach host organelles during beneficial plant-fungal interactions remains poorly understood. Here, we identify a class of secreted prion-like effector proteins from the mutualistic root endophyte Serendipita indica, termed PEPSIs. These proteins contain prion-like domains (PrLDs) embedded within intrinsically disordered regions, and three tested PEPSIs require these domains for plastid localization. Focusing on PEPSI6, we show that plastid targeting depends on its PrLD and is associated with engagement of plastid import and proteostasis machinery. In plastids, PEPSI6 associates with 1-deoxy-D-xylulose 5-phosphate reductoisomerase (DXR), promotes DXR accumulation, alters methylerythritol phosphate pathway metabolites, and enhances tolerance to the DXR inhibitor fosmidomycin. PEPSI6 also undergoes apoplastic C-terminal CAP-domain processing, and its colonization-promoting activity persists after PrLD deletion, indicating a plastid-targeting-independent function. Overall, this work identifies PrLDs as noncanonical plastid-targeting elements in PEPSI effectors and reveals DXR as a target of fungal manipulation during root symbiosis. HighlightsO_LIPrion-like domains control plastid targeting of selected PEPSI effectors. C_LIO_LIPEPSI6 associates with DXR and promotes its accumulation in plastids. C_LIO_LIPEPSI6 alters MEP-pathway metabolites and increases tolerance to fosmidomycin. C_LIO_LIApoplastic processing reveals a plastid-independent PEPSI6 activity during root symbiosis. C_LI

plant biology↗

bioRxiv2025

Thermal proteome profiling identifies mitochondrial aminotransferases involved in cysteine catabolism via persulfides in plants

Cysteine is a central metabolite in plant sulfur metabolism, with key roles in biosynthesis, redox regulation, and stress responses. While a mitochondrial cysteine degradation pathway has been described, the enzyme catalyzing its initial transamination step remained unidentified. Here, we applied thermal proteome profiling (TPP) to Arabidopsis mitochondria to uncover cysteine-interacting proteins. TPP successfully detected known cysteine-utilizing enzymes, validating its utility in plant metabolic research. Among newly identified targets were two aminotransferases annotated as alanine and aspartate aminotransferases that catalyze the transamination of cysteine to 3-mercaptopyruvate in vitro. These enzymes, together with the sulfurtransferase STR1 and the persulfide dioxygenase ETHE1, reconstituted a complete mitochondrial cysteine catabolic pathway. Kinetic data indicate that alanine aminotransferase, in particular, may function in vivo under physiological cysteine levels. Additionally, GABA aminotransferase was inhibited by cysteine, suggesting a regulatory role in stress metabolism. Beyond enzyme identification, the dataset provides a resource for exploring cysteine-mediated regulation of transporters, RNA-editing factors, and respiratory components. Given cysteines emerging role as a metabolic signal in stress responses, and the importance of allosteric regulation in amino acid metabolism, these findings highlight the broader regulatory potential of cysteine-protein interactions in plants. This study demonstrates the utility of TPP for elucidating metabolite-protein networks and advancing our understanding of plant mitochondrial metabolism.

plant biology↗

bioRxiv2025

Balancing nutrient remobilization and photosynthesis: the dual role of lupin cotyledons after germination

Efficient nutrient mobilization from seed storage tissues is essential for seedling establishment, particularly in legumes such as Lupinus albus (white lupin), which thrive in nutrient-poor soils. This study investigates the role of cotyledons in nitrogen (N) and mineral remobilization after germination during their transition from storage organs to photosynthetically active tissues including the metabolic challenges posed by coexistence of these two functions in epigeal germination. We cultivated white lupin seedlings under nitrogen-deficient conditions, analyzing cotyledon composition and function over 28 days. Our results indicate that 60 % of cotyledon-stored proteins are degraded within the first eight days, with free amino acids transiently accumulating before being redistributed to support growth. The progressive depletion of cotyledon reserves was accompanied by structural and metabolic changes, including an increase in photosynthetic proteins. However, cotyledon photosynthetic capacity remained lower than that of true leaves, suggesting a transient role in energy metabolism. The loss of cotyledons before day 12 significantly impaired seedling development, emphasizing their critical contribution to nitrogen, phosphate, and micronutrient supply during early growth. Comparative proteomic analysis revealed dynamic shifts in nutrient transport, amino acid metabolism, and stress response pathways following cotyledon removal. These findings underscore the significance of cotyledon nutrient remobilization in legume adaptation to low-fertility soils and highlight potential targets for breeding strategies aimed at improving nutrient use efficiency. By optimizing cotyledon nutrient composition and function, future breeding efforts could enhance seedling vigor, reduce fertilizer dependency, and improve the nutritional value of lupin-based foods. Significance statementThis study uncovers how white lupin cotyledons balance nutrient storage and photosynthesis during early seedling development, ensuring sustained nitrogen and mineral supply under nutrient-deficient conditions. By detailing the proteome reorganization and consequences of premature cotyledon loss, it identifies key mechanisms supporting seedling resilience and adaptation to low-fertility soils.

plant biology↗

bioRxiv2025

Cysteine signaling in plant pathogen response

The amino acid cysteine is the precursor for a wide range of sulfur-containing functional molecules in plants, including enzyme cofactors and defense compounds. Due to its redox active thiol group cysteine is highly reactive. Synthesis and degradation pathways are present in several subcellular compartments to adjust the intracellular cysteine concentration. However, stress conditions can lead to a transient increase in local cysteine levels. Here we investigate links between cysteine homeostasis and metabolic signaling in Arabidopsis thaliana. The systemic proteome response to cysteine feeding strongly suggests that Arabidopsis seedlings interpret accumulation of cysteine above a certain threshold as a signal for a biotic threat. Cysteine supplementation of Arabidopsis plants via the roots increases their resistance to the hemibiotrophic bacterium Pseudomonas syringae confirming the protective function of the cysteine induced defense pathways. Analysis of mutant plants reveals that the balance of cysteine synthesis between the cytosol and organelles is crucial during Arabidopsis immune response to Pseudomonas syringae. The induction profile of pathogen responsive proteins by cysteine provides insight into potential modes of action. Our results highlight the role of cysteine as a metabolic signal in the plant immune response and add evidence to the emerging concept of intracellular organelles as important players in plant stress signaling.

plant biology↗

bioRxiv2020

Estimating the number of protein molecules in a plant cell: a quantitative perspective on proteostasis and amino acid homeostasis during progressive drought stress

During dehydration cellular proteostasis as well as amino acid homeostasis are severely challenged, since the decrease in photosynthesis induces massive proteolysis. Thus, we selected progressive drought stress in Arabidopsis thaliana as a model to investigate the balance between protein and free amino acid homeostasis on a quantitative level. We analyze the mass protein composition of rosette leaves and estimate, how many protein molecules are present in a plant cell and its subcellular compartments. Under control conditions, an average Arabidopsis mesophyll cell contains about 25 billion protein molecules and 80% of them are localized in the chloroplasts. Severe water deficiency leads to degradation of more than 40% of the leaf proteome and thus causes a drastic shift towards the free amino acid pool. Stress induced proteolysis of half of the 400 million RubisCO hexadecamers present in the chloroplasts of an individual mesophyll cell alone doubles the cellular content in free amino acids. A major fraction of the amino acids released from proteins is channeled into the synthesis of proline as a compatible osmolyte. Complete oxidation of the remaining part as an alternative respiratory substrate can fully compensate the lack of carbohydrates derived from photosynthesis for several hours.

plant biology↗