Fischer, S. E. J. | bioRxiv Science

bioRxiv2023

Bacteria Are a Major Determinant of Orsay Virus Transmission and Infection in Caenorhabditis elegans

The microbiota is a key determinant of the physiology and immunity of animal hosts. The factors governing the transmissibility of viruses between susceptible hosts are incompletely understood. Bacteria serve as food for Caenorhabditis elegans and represent an integral part of the natural environment of C. elegans. We determined the effects of bacteria isolated with C. elegans from its natural environment on the transmission of Orsay virus in C. elegans using quantitative virus transmission and host susceptibility assays. We observed that Ochrobactrum species promoted Orsay virus transmission, whereas Pseudomonas lurida MYb11 attenuated virus transmission relative to the standard laboratory bacterial food Escherichia coli OP50. We found that pathogenic Pseudomonas aeruginosa strains PA01 and PA14 further attenuated virus transmission. We determined that the amount of Orsay virus required to infect 50% of a C. elegans population on P. lurida MYb11 compared with Ochrobactrum vermis MYb71 was dramatically increased, over three orders of magnitude. Host susceptibility was attenuated even further in presence of P. aeruginosa PA14. Genetic analysis of the determinants of P. aeruginosa required for attenuation of C. elegans susceptibility to Orsay virus infection revealed a role for regulators of quorum sensing. Our data suggest that distinct constituents of the C. elegans microbiota and potential pathogens can have widely divergent effects on Orsay virus transmission, such that associated bacteria can effectively determine host susceptibility versus resistance to viral infection. Our study provides quantitative evidence for a critical role for tripartite host-virus-bacteria interactions in determining the transmissibility of viruses among susceptible hosts.

microbiology↗

bioRxiv2021

Neuronal control of maternal provisioning in response to social cues

Mothers contribute cytoplasmic components to their progeny in a process called maternal provisioning. Provisioning is influenced by the parental environment, but the molecular pathways that transmit environmental cues from mother to progeny are not well understood. Here we show that in C. elegans, social cues modulate maternal provisioning to regulate gene silencing in offspring. Intergenerational signal transmission depends on a pheromone-sensing neuron and neuronal FMRF (Phe-Met-Arg-Phe)-like peptides. Parental FMRF signaling promotes the deposition of mRNAs for translational components in progeny, which in turn reduces gene silencing. Previous studies had implicated FMRF signaling in short-term responses such as modulated feeding behavior in response to the metabolic state1,2, but our data reveal a broader role, to coordinate energetically expensive processes such as translation and maternal provisioning. This study identifies a new pathway for intergenerational communication, distinct from previously discovered pathways involving small RNAs and chromatin, that links sensory perception to maternal provisioning.

genetics↗