Publications

4478

AbstractBACKGROUNDCitrus huanglongbing (HLB) is a devastating disease caused by Candidatus Liberibacter asiaticus (CLas) that affects the citrus industry. In nature, CLas relies primarily on Diaphorina citri Kuwayama as its vector for dissemination. After D. citri ingests CLas‐infected citrus, the pathogen infiltrates the insect's body, where it thrives, reproduces, and exerts regulatory control over the growth and metabolism of D. citri. Previous studies have shown that CLas alters the composition of proteins in the saliva of D. citri, but the functions of these proteins remain largely unknown.RESULTSIn this study, we detected two proteins (DcitSGP1 and DcitSGP3) with high expression levels in CLas‐infected D. citri. Quantitative PCR and Western blotting analysis showed that the two proteins were highly expressed in the salivary glands and delivered into the host plant during feeding. Silencing the two genes significantly decreased the survival rate for D. citri, reduced phloem nutrition sucking and promoted jasmonic acid (JA) defenses in citrus. By contrast, after overexpressing the two genes in citrus, the expression levels of JA pathway‐associated genes decreased.CONCLUSIONOur results suggest that CLas can indirectly suppress the defenses of citrus and support feeding by D. citri via increasing the levels of effectors in the insect's saliva. This discovery facilitates further research into the interaction between insect vectors and pathogens. © 2024 Society of Chemical Industry.

AbstractThe roles of Asgard archaea in eukaryogenesis and marine biogeochemical cycles are well studied, yet their contributions in soil ecosystems remain unknown. Of particular interest are Asgard archaeal contributions to methane cycling in wetland soils. To investigate this, we reconstructed two complete genomes for soil-associated Atabeyarchaeia, a new Asgard lineage, and a complete genome of Freyarchaeia, and predicted their metabolism in situ. Metatranscriptomics reveals expression of genes for [NiFe]-hydrogenases, pyruvate oxidation and carbon fixation via the Wood-Ljungdahl pathway. Also expressed are genes encoding enzymes for amino acid metabolism, anaerobic aldehyde oxidation, hydrogen peroxide detoxification and carbohydrate breakdown to acetate and formate. Overall, soil-associated Asgard archaea are predicted to include non-methanogenic acetogens, highlighting their potential role in carbon cycling in terrestrial environments.

The aim of this work was to report the molecular diagnosis of Mycoplasma haemofelis and 'Candidatus Mycoplasma haemominutum' in a domestic feline. Mycoplasma spp. are pleomorphic bacteria that parasitize the surface of red blood cells in several domestic species, mainly cats, being responsible for feline mycoplasmosis, which can cause hemolytic anemia. Cats can become infected through blood transfusions, social interactions via fights and flea bites. In this report, the patient exhibited in the clinical exam, pale and icteric mucous membranes, and enlargement of the popliteal and submandibular lymph nodes. Based on the symptoms presented, a blood sample was collected to search for hemoparasites using blood smears and also molecular examination by polymerase chain reaction (PCR). The blood smear revealed inclusions characteristic of Mycoplasma spp. Observed in red blood cells, and the diagnosis of mycoplasmosis was confirmed by PCR. This report highlights the importance of screening for hemoparasites in the feline clinical routine, with molecular tests being the most recommended due to their high sensitivity and specificity.

AbstractMembers of the phylum Gemmatimonadota can account for up to 10% of the phylogenetic diversity in bacterial communities. However, a detailed investigation of their cell biology and ecological roles is restricted by currently only six characterized species. By combining low-nutrient media, empirically determined inoculation volumes and long incubation times in a 96-well plate cultivation platform, we isolated two strains from a limnic sponge that belong to this under-studied phylum. The characterization suggests that the two closely related strains constitute a novel species of a novel genus, for which we introduce the name Pseudogemmatithrix spongiicola. The here demonstrated isolation of novel members from an under-studied bacterial phylum substantiates that the cultivation platform can provide access to axenic bacterial cultures from various environmental samples. Similar to previously described members of the phylum, the novel isolates form spherical appendages at the cell poles that were believed to be daughter cells resulting from asymmetric cell division by budding. However, time-lapse microscopy experiments and quantitative image analysis showed that the spherical appendages never grew or divided. Although the role of these spherical cells remains enigmatic, our data suggests that cells of the phylum Gemmatimonadota divide via FtsZ-based binary fission with different division plane localization patterns than in other bacterial phyla.

ABSTRACT The complete genome of “ Candidatus Phytoplasma fraxini” AshY1, originating from Fraxinus americana in North America, was assembled using long reads from single-molecule real-time sequencing technology. The chromosome of 598 kb provides insights into the effector repertoire of a phytopathogenic bacterium from the 16SrVII phytoplasma group.

ABSTRACT This study reports a circular metagenome-assembled genome (cMAG) of Candidatus Cloacimonadota recovered from a mesophilic full-scale food waste treatment plant. The cMAG spans 2,298,113 bp, with 980× coverage and 1 contig.

AbstractPsyllid species, including the potato psyllid (PoP) Bactericera cockerelli (Sulc) (Triozidae) serve as host and vector of “Candidatus Liberibacter spp.” (“Ca. Liberibacter”), which also infects diverse plant hosts, including citrus and tomato. Psyllid transmission of “Ca. Liberibacter” is circulative and propagative. The time of “Ca. Liberibacter” acquisition and therefore vector life stage most competent for bacterial transmission varies by pathosystems. Here, the potato psyllid-“Ca. Liberibacter solanacearum” (CLso) pathosystem was investigated to dissect CLso-prophage interactions in the tomato plant and PoP-psyllid host by real-time quantitative reverse transcriptase amplification of CLso genes/loci with predicted involvement in host infection and psyllid-CLso transmission. Genes/loci analyzed were associated with (1) CLso-adhesion, -invasion, -pathogenicity, and -motility, (2) prophage-adhesion and pathogenicity, and (3) CLso-lysogenic cycle. Relative gene expression was quantified by qRT-PCR amplification from total RNA isolated from CLso-infected 1st–2nd and 4th–5th nymphs and teneral adults and CLso-infected tomato plants in which CLso infection is thought to occur without SC1-SC2 replication. Gene/loci expression was host-dependent and varied with the psyllid developmental stage. Loci previously associated with repressor-anti-repressor regulation in the “Ca Liberibacter asiaticus”-prophage pathosystem, which maintains the lysogenic cycle in Asian citrus psyllid Diaphorina citri, were expressed in CLso-infected psyllids but not in CLso-infected tomato plants.

Objective/Background. Bocconia frutescens (Papaveraceae) is a small tree distributed naturally from Mexico to Argentina and the Caribbean Bassin. Bocconia trees showing symptoms resembling phytoplasmas infection, such as little leaves and witches´-broom, were found in Cartago province, Costa Rica. Detection and identification of the potential phytoplasmas associated with B. frutescens little leaf symptoms was the objective out of this study. Materials and Methods. Evaluation of leaves tissue using transmission electron microscopy (TEM), nested PCR using universal and specific primers to amplify phytoplasmas 16S rRNA and secA genes. Nucleotidic sequences (Sanger method) were obtained from amplicons, and used for BLASTn, phylogenetic analyses, and in silico RFLP’s. Results. Presence of phytoplasmas into phloem tissue, only in symptomatic trees, was evidenced by TEM. Comparison of partial sequences (16Sr and secA genes) by BLASTn, in silico RFLP´s and phylogenetic analyses, showed the occurrence of a ´Candidatus Phytoplasma pruni´ related strain in the samples evaluated. Conclusion. Phytoplasmas were found only in the symptomatic B. frutescens trees evaluated. The phytoplasmas were identified as a ´Ca. Phytoplasma pruni´ related strain. This is the first report of B. frutescens as a natural host of ´Ca. Phytoplasma pruni´.