Addressing the challenges of symbiont-mediated RNAi in aphids.

Because aphids are global agricultural pests and models for bacterial endosymbiosis, there is a need for reliable methods to study and control their gene function. However, current methods available for aphid gene knockout and knockdown of gene expression are often unreliable and time consuming. Techniques like CRISPR-Cas genome editing can take several months to achieve a single gene knockout because they rely on aphids going through a cycle of sexual reproduction, and aphids often lack strong, consistent levels of knockdown when fed or injected with molecules that induce an RNA interference (RNAi) response.

Elucidation of host and symbiont contributions to peptidoglycan metabolism based on comparative genomics of eight aphid subfamilies and their Buchnera.

Pea aphids (Acyrthosiphon pisum) are insects containing genes of bacterial origin with putative functions in peptidoglycan (PGN) metabolism. Of these, rlpA1-5, amiD, and ldcA are highly expressed in bacteriocytes, specialized aphid cells that harbor the obligate bacterial symbiont Buchnera aphidicola, required for amino acid supplementation of the host's nutrient-poor diet. Despite genome reduction associated with endosymbiosis, pea aphid Buchnera retains genes for the synthesis of PGN while Buchnera of many other aphid species partially or completely lack these genes.

Strong within-host selection in a maternally inherited obligate symbiont: and aphids.

Numerous animal lineages have maternally inherited symbionts that are required for host reproduction and growth. Endosymbionts also pose a risk to their hosts because of the mutational decay of their genomes through genetic drift or to selfish mutations that favor symbiont fitness over host fitness. One model for heritable endosymbiosis is the association of aphids with their obligate bacterial symbiont, We experimentally established heteroplasmic pea aphid matrilines containing pairs of closely related haplotypes and used deep sequencing of diagnostic markers to measure haplotype frequencies in successive host generations.

Vertical Transmission at the Pathogen-Symbiont Interface: Serratia symbiotica and Aphids.

Many insects possess beneficial bacterial symbionts that occupy specialized host cells and are maternally transmitted. As a consequence of their host-restricted lifestyle, these symbionts often possess reduced genomes and cannot be cultured outside hosts, limiting their study. The bacterial species was originally characterized as noncultured strains that live as mutualistic symbionts of aphids and are vertically transmitted through transovarial endocytosis within the mother's body.

Division of labor in honey bee gut microbiota for plant polysaccharide digestion.

Bees acquire carbohydrates from nectar and lipids; and amino acids from pollen, which also contains polysaccharides including cellulose, hemicellulose, and pectin. These potential energy sources could be degraded and fermented through microbial enzymatic activity, resulting in short chain fatty acids available to hosts. However, the contributions of individual microbiota members to polysaccharide digestion have remained unclear.

Correction: Longitudinal microbiome profiling reveals impermanence of probiotic bacteria in domestic pigeons.

[This corrects the article DOI: 10.1371/journal.pone.

Longitudinal microbiome profiling reveals impermanence of probiotic bacteria in domestic pigeons.

Probiotics are bacterial species or assemblages that are applied to animals and plants with the intention of altering the microbiome in a beneficial way. Probiotics have been linked to positive health effects such as faster disease recovery times in humans and increased weight gain in poultry. Pigeon fanciers often feed their show pigeons probiotics with the intention of increasing flight performance.

Decomposing parasite fitness reveals the basis of specialization in a two-host, two-parasite system.

The ecological specialization of parasites-whether they can obtain high fitness on very few or very many different host species-is a determining feature of their ecology. In order to properly assess specialization, it is imperative to measure parasite fitness across host species; to understand its origins, fitness must be decomposed into the underlying traits. Despite the omnipresence of parasites with multiple hosts, very few studies assess and decompose their specialization in this way.