Publications

4509

Abstract Background Rare species, especially of the marine sedimentary biosphere, have long been overlooked owing to the complexity of sediment microbial communities, their sporadic temporal and patchy spatial abundance, and challenges in cultivating environmental microorganisms. In this study, we combined enrichments, targeted metagenomic sequencing, and extensive data mining to uncover uncultivated members of the archaeal rare biosphere in marine sediments. Results In protein-amended enrichments, we detected the ecologically and metabolically uncharacterized class Candidatus Penumbrarchaeia within the phylum Thermoplasmatota. By screening more than 8000 metagenomic runs and 11,479 published genome assemblies, we expanded the phylogeny of Ca. Penumbrarchaeia by 3 novel orders. All six identified families of this class show low abundance in environmental samples characteristic of rare biosphere members. Members of the class Ca. Penumbrarchaeia were predicted to be involved in organic matter degradation in anoxic, carbon-rich habitats. All Ca. Penumbrarchaeia families contain high numbers of taxon-specific orthologous genes, highlighting their environmental adaptations and habitat specificity. Besides, members of this group exhibit the highest proportion of unknown genes within the entire phylum Thermoplasmatota, suggesting a high degree of functional novelty in this class. Conclusions In this study, we emphasize the necessity of targeted, data-integrative approaches to deepen our understanding of the rare biosphere and uncover the functions and metabolic potential hidden within these understudied taxa.

AbstractBACKGROUNDAlthough it is known that Candidatus Liberibacter asiaticus (CLas), the agent of citrus Huanglongbing, circulates and multiplies within the insect vector Diaphorina citri, the specific factors enabling CLas transmission remain unclear. Previous studies have shown that ATPSyn‐β facilitates phytoplasma movement in vector insects, and functions as a transport protein in D. citri. In this study, the role of ATPSyn‐β was expected to be unveiled in CLas transmission in D. citri.RESULTSThe interaction between ATPSyn‐β of D. citri and the outer membrane protein A (OmpA) of CLas was identified using glutathione S‐transferase pull‐down and yeast two‐hybrid assays. No interactions existed between OmpA and vitellogenin (Vg). Bioinformatics analysis revealed that ATPSyn‐β contained two conserved domains, ATP‐synt_ab_N and ATP‐synt_ab. Notably, ATP‐synt_ab_N interacted with both OmpA and Vg, indicating a competitive relationship between Vg and OmpA for binding to ATPSyn‐β. After silencing ATPSyn‐β expression using RNAi, the feeding behavior of D. citri decreased, resulting in a lower acquisition of CLas. Subsequently, this inhibited CLas movement within D. citri and reduced the inoculation of CLas to healthy citrus plants.CONCLUSIONATPSyn‐β was involved in the acquisition, movement in vivo, and inoculation of CLas by interacting with OmpA, thus offering a novel target to prevent the spread of citrus Huanglongbing. © 2025 Society of Chemical Industry.

Abstract Aim Candidatus Methanoperedens-related archaea have recently been identified as anaerobic methane oxidizers in paddy soils. Fertilization practices, including the application of inorganic and organic fertilizers (e.g. chicken manure), may significantly influence their community dynamics and the associated methane cycling processes. However, the comparative effects of inorganic and chicken manure fertilization on these archaeal community in paddy fields remain unclear. This study aimed to examine the diversity, community composition, and abundance of Methanoperedens-related archaea at three representative soil layers of 0–10, 20–30, and 40–50 cm under three fertilization treatments (no fertilizer, inorganic fertilizer, chicken manure fertilizer). Methods and results High-throughput sequencing revealed significant differences in community composition among treatments, while overall diversity showed minimal changes. Quantitative Polymerase Chain Reaction indicated that archaeal abundance under inorganic (2.3 × 106 copies g−1) and chicken manure fertilization (2.2 × 106 copies g−1) treatments was significantly greater than that under no fertilization (1.8 × 106 copies g−1) in upper 30 cm soils, with no significant difference at 40–50 cm depth. Inorganic fertilization more strongly promoted archaeal abundance, whereas chicken manure had a greater effect on community structure. Soil ammonium, nitrate, and organic carbon contents were significantly correlated with archaeal community patterns. Conclusion Both inorganic and organic fertilization can substantially influence the community structure and abundance of Methanoperedens-related archaea in paddy soils.

Ticks spread pathogens that affect both human and animal health and often cause significant economic losses to the livestock industry. However, there is limited data on the distribution of ticks and tick-borne pathogens, particularly those affecting cattle in Cameroon. In this study, ticks were collected from cattle in Buea, the capital of the South West Region of Cameroon, to determine their diversity and identify tick-borne pathogens through PCR and sequencing. The tick samples were screened for pathogens using assays that target the rOmpA gene (ompA) of Rickettsia, the ssrRNA gene of Babesia and Theileria and the Ehrlichia genus 16SrRNA gene. A total of 458 ticks were collected with Rhipicephalus annulatus (65.6%) as the predominant species. From 68 tick pools screened, 26 (38.2%) were positive for pathogen/ symbiont DNA. The pathogen identified was Rickettsia africae (22.1%). This study reports the first molecular detection of the symbiont Candidatus Midichloria mitochondrii (22.1%) in the sampled tick species. It was observed that male ticks were significantly more likely to test positive for R. africae (OR = 208, 95% CI = 28.6 - 4553, p<0.001). Animal handlers may face the risk of these zoonotic infections and as such, there is a need to employ protective measures to prevent or reduce pathogen spread.