Laport, M. S. | bioRxiv Science

bioRxiv2026

Genome Mining and Pangenome Analysis of the Stutzerimonas Genus: a Novel Source of Plastic-Degrading Enzymes

Nowadays, finding new sustainable ways to combat plastic pollution is a pressing challenge. Here, we provide a comprehensive genome mining analysis of 284 publicly available Stutzerimonas genomes for potential PET-active enzymes (PETases). While Stutzerimonas is a relatively newly established genus, it emerges as an interesting candidate in the search for novel biocatalysts. Hence, the first pangenome assessment of this genus based on its high-quality publicly available genomes was performed. An increasingly open pangenome was revealed, suggesting the versatility and adaptability of these strains to a variety of ecological niches. Moreover, functional characterisation of a new isolate, Stutzerimonas frequens VG-9, was carried out, confirming that enzymes found via in silico analyses may indeed display activity towards different polyesters. In summary, this study provides insights into the diversity of PETase homologues within still underexplored bacterial hosts, offering new perspectives for enzyme discovery in the Pseudomonadaceae family. Impact StatementMicrobial enzymes known as PETases have emerged as promising candidates for the biological degradation of PET. This study investigated the potential of underexplored bacterial genera by genome mining of PETase homologues. Our findings provide new insights into the distribution of PETase-like enzymes in the Pseudomonadaceae family, offering a more comprehensive view of their plastic degradation capacity. These results hold practical implications for the development of optimized enzyme discovery strategies, while also highlighting the vast genetic plasticity of Pseudomonadaceae. We also provided the first report on the Stutzerimonas pangenome and insights into the enzymatic activity towards polyesters of a newly isolated strain. Hence, the role of this genus as a highly adaptable and versatile entity was reinforced, further disclosing it as a potential source of novel biocatalysts. Data SummaryThe genome of S. frequens VG9 has been deposited in Genbank under the accession number SAMN49487720. The accession numbers of all analyzed genomes are listed in Tables S2 and S3 (available in the online Supplementary Material).

microbiology↗

bioRxiv2025

Loss of Vitellogenin Receptor Function Results in Yolk Depletion, Virome Expansion and Reduced Bacterial Load Within the Oocytes of Rhodnius prolixus

The vitellogenin receptor (VgR) mediates yolk protein uptake during oogenesis and is essential for embryogenesis in oviparous species. Here we characterize the single Rhodnius prolixus VgR isoform and uncover an unexpected role in microbial regulation within the reproductive system. The receptor displays a conserved LDLR-like structure and is highly expressed in early oocytes. RNAi-mediated VgR silencing caused defective yolk granule biogenesis, leading to the accumulation of the main yolk protein precursors, Vg and RHBP, in the hemolymph, yet oviposition and fertilization proceeded normally. The resulting eggs were yolk-depleted and non-viable. Remarkably, VgR knockdown reduced bacterial 16S rRNA levels in oocytes while promoting the expansion of several members of the core virome, a phenotype not reproduced by Vg silencing. Neither purified Vg nor changes in immune (defensin) or RNA interference pathways explained the microbial shifts. These findings indicate that VgR governs not only yolk endocytosis but also the trafficking of microbial components into developing oocytes. We propose that VgR contributes to the linking of yolk endocytic dynamics and microbial homeostasis, influencing the balance of microbial components within developing oocytes. This connection broadens the functional scope of the VgR and provides new insight into how vertical transmission processes are shaped in this major Chagas disease vector. Author summaryEgg-laying animals must load their eggs with enough nutrients to support early development. In insects, this process depends on a receptor that brings yolk proteins into the growing egg. Here, we studied this receptor in Rhodnius prolixus, a major vector of Chagas disease, and uncovered an unexpected link between yolk uptake and the microorganisms that enter the egg. When we blocked the receptor, females continued to produce and lay eggs, but these eggs failed to accumulate yolk and could not support embryonic development. Strikingly, the absence of the receptor also shifted the microbial community inside the oocyte: bacterial levels dropped, while several viruses expanded. These changes did not result from differences in yolk proteins, immune activation, or direct antimicrobial effects, indicating that the receptor itself influences microbial entry or persistence in the egg. Our findings reveal that this yolk receptor plays a dual role, providing nutrients and shaping the microbial community that is passed from mother to offspring. This work highlights an unrecognized layer of interaction between reproduction and microbial transmission in an important disease vector, offering new perspectives for understanding and potentially disrupting vertical transmission pathways.

cell biology↗