Publications

4869

Candidatus Saccharibacteria (TM7) is an underexplored bacterial group within the human oral microbiome. These ultra-small, host-dependent organisms, despite their reduced genomes, significantly influence microbial balance and host immunity, exhibiting dual roles in oral health and disease and emerging as a key focus in microbiome research. This systematic review aimed to synthesize evidence on the prevalence, host interactions, genomic features, and ecological roles of TM7 in the oral cavity. A total of 13 peer-reviewed studies published between 2020 and 2025 were selected for detailed review based on predefined inclusion criteria, including clinical, laboratory, and metagenomic analyses focusing on TM7 detection, isolation, host specificity, and interactions with oral microbial communities. TM7 was found to be predominantly oral-adapted, exhibiting site-specific colonization with higher abundance in saliva. Coculture experiments demonstrated strict host dependence, particularly on Actinomyces, Schaalia, and Arachnia species, with strain-specific variations affecting host viability and microbial networks. TM7 genomes are highly reduced, with specialized adaptations including type IV pili and arginine deiminase pathways. Interactions with the immune system were context-dependent, with both immunomodulatory and pro-inflammatory outcomes observed. Detection methods significantly influenced TM7 prevalence and functional interpretation. Overall, TM7 represents a host-dependent, ecologically influential oral bacterium with genomic specialization, strain-level variability, and complex interactions within microbial communities. These findings highlight its potential roles in oral health and disease and emphasize the need for advanced multi-modal analytical approaches.

Abstract The pear psyllid Cacopsylla pyri is the main vector of ‘ Candidatus Phytoplasma pyri’, the causal agent of pear decline, a disease associated with severe yield losses in pear production. Phytoplasmas are further known to interfere with their vectors metabolism; therefore, we investigated whether an infection with ‘ Ca. P. pyri’ is associated with changes in nutrient storage of the pear psyllids. Additionally, we measured whether the phytoplasma infection is associated with differences in flight performance in C. pyri , as the flight activity of the vector is a key component of phytopathogen spread. Using a flight mill, we quantified flight distance, duration, and speed, and combined qPCR-based infection detection with colorimetric assays to determine protein, carbohydrate, and lipid content from the same individual. Infected psyllids contained significantly higher levels of soluble carbohydrates than uninfected individuals. Lipid content was not affected by the phytoplasma infections but was found to be consistently higher in males than in females, while protein levels did not vary with sex or infection status. Despite infection-related differences in carbohydrate levels, phytoplasma infection did not significantly affect flight duration, distance, or speed. These results indicate that infection-associated shifts in bulk carbohydrate storage do not translate into altered flight motivation or performance, suggesting a functional decoupling between metabolic state and realised dispersal capacity under standardised laboratory conditions.

Abstract Since 2025, EFSA has conducted expert knowledge elicitations to estimate survey parameters for the detection of EU priority pests listed in Commission Delegated Regulation (EU) 2019/1702, in cases where pest‐specific information is lacking in the scientific literature. The design and implementation of statistically sound and risk‐based surveys require quantitative parameters such as sampling effectiveness, design prevalence and relative risk. This report presents the estimated values for Bactericera cockerelli and ‘Candidatus Liberibacter solanacearum’, together with the supporting evidence and expert rationale. These values will be integrated into the EFSA Plant Pest Survey Toolkit to guide EU Member States in designing harmonised pest surveys across the EU.

Candidatus Liberibacter solanacearum (CLso), a pathogen of concern to the potato industry, which causes zebrachip disease, is vectored by the tomato/potato psyllid [ Bactericera cockerelli (Šulc)]. This study investigated whether Lycium ferocissimum acts as an overwintering green bridge enabling pathogen survival, while potatoes are absent. The potential of L. ferocissimum to act as a green bridge for other pathogens was also investigated. African boxthorn leaf samples were taken in Feb, Mar, and Apr 2023 in Canterbury, New Zealand, and endophytes were isolated and cultured. DNA was extracted from these pure-cultured endophytes as well as from leaves. Molecular methods were used to identify the cultured endophytes and to determine the presence of CLso. This study found several potentially pathogenic endophytes including Alternaria porri, Stemphylium eturmiunum , Stemphylium vesicarium, Pseudomonas spp., Erwinia spp. , Pantoea sp. , and Candidatus Liberibacter solanacearum. The percentage of leaves which tested positive for CLso increased from 2% in Feb 2023 to 39% in Apr 2023. CLso was found in leaves without evidence of psyllid feeding, which may indicate systemic infection of African Boxthorn, suggesting the plant acts as a green bridge plant. It is highly recommended that this plant be eradicated within the vicinity of potatoes and other Solanaceous crops.

ABSTRACT Leptothrix mechoopdaensis BB-3 and BB-4 are metal-oxidizing, sheathed, filamentous bacteria that were isolated from a woodland iron seep near Centerville, Chico, CA, USA. Here, we report a closed circular genome sequence for each strain, assembled from reads sequenced on an Oxford Nanopore FLO-MIN114 flow cell.