Molecular Biology

Host acquisition of a new microbial species can readily perturb the dynamics of preexisting microbial associations. Molecular cross talk between microbial associates may be necessary for efficient resource allocation and enhanced survival. Classic examples involve quorum sensing (QS), which detects population densities and is both used and coopted to control expression of bacterial genes, including host adaptation factors. We report that a 56-amino-acid repressor protein made by the resident psyllid endosymbiont Wolbachia can enter cells of Liberibacter crescens , a cultured proxy for the uncultured psyllid endosymbiont “ Ca . Liberibacter asiaticus” and repress “ Ca . Liberibacter asiaticus” phage lytic cycle genes. Such repression in “ Ca . Liberibacter asiaticus” may be critical to survival of both endosymbionts, since phage-mediated lysis would likely breach the immunogenic threshold of the psyllid, invoking a systemic and nonspecific innate immune reaction.

ABSTRACT Here, we report the genome of “ Candidatus Carsonella ruddii” strain BC, a nutritional endosymbiont of the tomato psyllid Bactericera cockerelli . The 173,802-bp genome contains 198 protein-coding genes, with a G+C content of 14.8%.

ABSTRACT We report here four draft genome sequences belonging to clade F of the cyanobacterium “ Candidatus Synechococcus spongiarum” of the marine sponge Aplysina aerophoba , which were collected from two nearby locations in the northern Adriatic Sea. The sequences provide the basis for within-clade comparisons between members of this widespread group of cyanobacterial sponge symbionts.

Bacteria that directly use electrodes as metabolic electron donors (biocathodes) have been proposed for applications ranging from microbial electrosynthesis to advanced bioelectronics for cellular communication with machines. However, just as we understand very little about oxidation of analogous natural insoluble electron donors, such as iron oxide, the organisms and extracellular electron transfer (EET) pathways underlying the electrode-cell direct electron transfer processes are almost completely unknown. Biocathodes are a stable biofilm cultivation platform to interrogate both the rate and mechanism of EET using electrochemistry and to study the electroautotrophic organisms that catalyze these reactions. Here we provide new evidence supporting the hypothesis that the uncultured bacterium “ Candidatus Tenderia electrophaga” directly couples extracellular electron transfer to CO 2 fixation. Our results provide insight into developing biocathode technology, such as microbial electrosynthesis, as well as advancing our understanding of chemolithoautotrophy.

ABSTRACT We report here the draft genome sequence of “ Candidatus Liberibacter asiaticus” strain TX2351, collected from Asian citrus psyllids in south Texas, USA. The TX2351 genome has a size of 1,252,043 bp, a G+C content of 36.5%, 1,184 predicted open reading frames, and 52 RNA genes.

ABSTRACT “ Candidatus Synechococcus spongiarum” represents the widespread cyanobacterial symbionts found in marine sponges with relatively high genomic variability and likely important ecological roles. We present here the draft genome sequence of “ Candidatus Synechococcus spongiarum” m9, which was assembled from a metagenome of Theonella swinhoei sampled in the South China Sea.