Publications

4681

Abstract Background ‘ Candidatus Liberibacter solanacearum’ (Lso) is a phloem-limited bacterial pathogen causing significant diseases in solanaceous crops. In the United States, haplotypes A and B are transmitted by the potato psyllid Bactericera cockerelli . We previously identified differences in their acquisition and transmission between adults and nymphs. The present study characterized the dynamics of LsoA and LsoB acquisition and transmission by nymphs and examined the transcriptional responses of the nymphal gut upon their acquisition. Methods and results Nymphs were exposed to LsoA- or LsoB-infected plants for 1, 3, 5, or 7 days to measure the bacterial accumulation and for 8 days to assess the transmission efficiency following sequential inoculation of tomato plants. Quantitative PCR showed that LsoB accumulated to higher levels than LsoA after 3 days of acquisition. Following the sequential inoculation, LsoB was transmitted earlier than LsoA indicating a shorter latency period. RNA-seq analysis of the guts following a 1- and 5-day acquisition access periods revealed a greater transcriptional regulation at 5 days than at 1 day. Furthermore, the responses were haplotype-specific: LsoA primarily affected genes involved in protein translation, ER stress, and cell cycle regulation, whereas LsoB regulated genes involved in autophagy, apoptosis, and immune pathways. Conclusions This study revealed haplotype-specific gene regulation potentially leading to LsoB being transmitted more efficiently by psyllid nymphs.

Abstract Bovine hemoplasmas, including Mycoplasma wenyonii (M. wenyonii) and Candidatus Mycoplasma haemobos (C. M. haemobos) , are vector-borne pathogens that can cause significant clinical diseases in cattle. This case report from Türkiye describes the clinical findings, hematological analysis, and serum biochemistry results of a cow presenting with hemoglobinuria caused by C. M. haemobos . Blood samples from the infected animal were analyzed using hematological, biochemical, microscopic, and molecular methods. Multiplex polymerase chain reaction assay confirmed the infection, and microscopic analysis revealed a parasitemia rate of 6.99%. Clinical signs included hemoglobinuria, icterus, and anemia. The treatment included fluid therapy, antibiotic (oxytetracycline), and antianemic drugs. The cattle died 1 month post-treatment, reportedly due to a lower respiratory tract infection. This case report describes the diagnostic methods, clinical findings, and laboratory results. A widescale molecular survey of C. M. haemobos in cattle is warranted, with investigation of its pathogenicity and pathogenies.

Background: The Asian Haemaphysalis longicornis is capable of transmitting a wide range of zoonotic pathogens. This study aimed to investigate the prevalence and characteristics of major pathogens in questing H. longicornis ticks collected from two geographically and ecologically distinct regions in China. Methods: A total of 1004 questing H. longicornis ticks were collected from Liaoning Province (Northeast China; n = 882) and Anhui Province (Central and Eastern China; n = 122) and pooled into 670 mixed samples. Tick species were identified by mitochondrial cytochrome oxidase I gene sequencing. Nucleic acid samples from all pools were first screened for Dabie bandavirus using RT-PCR and for bacteria using universal 16S rRNA primers. Bacteria-positive samples were further tested using polygenic seminested PCR for Rickettsia spp. and Coxiella -like endosymbionts (CLEs). Phylogenetic analyses, including polygene sequence analysis, were performed to ensure the accuracy of species identification and to explore genetic relationships. Results: No Dabie bandavirus was detected in any samples. Among the 670 tick pools, 14 were positive for spotted fever group rickettsiae (SFGR), with an overall minimum infection rate (MIR) of 1.4% (14/1004). Notably, the detected SFGR species showed clear geographic segregation: Candidatus Rickettsia jingxinensis was detected only in Liaoning Province (MIR of 1.4%), while Rickettsia heilongjiangensis was found exclusively in Anhui Province (MIR of 1.6%). Additionally, CLEs (overall MIR of 2.0%) were identified in 20 tick pools, with a significantly higher prevalence in Anhui Province (10.7%) than in Liaoning Province (0.8%; p < 0.001). Conclusions: This surveillance revealed a distinct geographical distribution pattern of SFGR species in H. longicornis populations in China and confirmed the presence of Ca . R. jingxinensis in the northeast and R. heilongjiangensis in the central and eastern regions. These findings, supported by polygenic evidence, provide essential epidemiological data for understanding regional tick-borne disease risks and highlight the need for continued region-specific surveillance.

Abstract The demand for D-amino acids is increasing as their unique physiological role continues to be elucidated. meso-Diaminopimelate dehydrogenase catalyzes the reversible NADP+-dependent oxidative deamination of meso-diaminopimelate to produce L-2-amino-6-oxopimelate. Moreover, a few enzymes show a broad range of reductive amination activity toward 2-oxo acids, synthesizing D-amino acids. Here, we report the identification and characterization of a novel NADP+-dependent meso-diaminopimelate dehydrogenase from Candidatus Syntrophocurvum alkaliphilum (CSaDAPDH). The purified enzyme exhibited oxidative deamination activity toward meso-diaminopimelate, as well as reductive amination activity toward several 2-oxo acids to produce the corresponding D-amino acids. The optimum pH and temperature for oxidative deamination of meso-diaminopimelate were 9.0 and 45°C, respectively. The optimum pH for reductive amination of pyruvate was 6.5, which was the lowest optimum pH among known enzymes, and thus, may lead to the development of new enzymatic methods for D-amino acid production. CSaDAPDH retained more than 60% of its activity after incubation for 30 min at 50°C (pH 7.0) or at pHs ranging from 5.5 to 7.0 (50°C). Moreover, using known enzymes as comparisons, the coenzyme and substrate recognition mechanisms of CSaDAPDH were elucidated based on a multiple sequence alignment and the homology model.

Bambusa multiplex, one of the most acclimatized clumping-bamboo species, has been broadly cultivated in China and has significant economical, ecological and ornamental importance (Yuan et al. 2009). In November 2025, more than 30% of B. multiplex plants exhibiting typical witches’ broom, internode shortening, leaf proliferation and clustering of leaves were observed in a horticultural landscaping field in Zhangjiang city, Guangdong Province, China. To confirm the presence of a phytoplasma, total DNA was extracted from fresh leaves of ten symptomatic and four asymptomatic plants using the CTAB method. Conventional nested PCR was performed using primer pairs P1/P7 followed by R16F2n/R16R2 (Gundersen and Lee, 1996), and expected fragment amplified only from the symptomatic plants. The PCR products were sequenced, and deposited in GenBank under the accession number PX998769. BLAST analysis revealed that the sequence shared 99.60% identity with that of the SPLL subgroup reference strain ‘Candidatus Phytoplasma australasiaticum subsp. Ipomoeae’ o7C (GenBank accession no. GCA_024425275.1, 1,244/1,249 bp) (Rodrigues Jardim et al. 2023). Further virtual RFLP pattern analysis of the 16S rRNA sequence by iPhyClassifier (Zhao et al. 2009) verified that the phytoplasma strain, designated as BMW-ZJ, was a member of the 16SrII-A subgroup with a 1.00 similarity coefficient to the reference phytoplasma strain (GenBank accession no. L33765). Moreover, the secY gene was amplified using primer pairs secYwbF1/secYwbR1 followed by secYwbF2/secYwbR2 (Wang et al. 2025), and the sequence(GenBank accession no. PZ135411) shared 100% identity to several ‘Ca. P. australasiaticum’ strains (NTU2011, BAWM-TWN and BAWM-THA-CLP). Phylogenetic analysis based on the 16S rRNA and secY genes conducted by MEGA 12 (Kumar et al. 2024), confirmed that BMW-ZJ was related to ‘Ca. P. australasiaticum’(Bertaccini et al. 2022; Rodrigues Jardim et al. 2023). Earlier, 16SrII phytoplasma associated with bamboo species Dendrocalamus giganteus (Che et al. 2024), and 16SrI phytoplasma associated with Sasa fortunei (Zhang et al. 2009) were reported in Hainan and Shaanxi Province, China, respectively. To our knowledge, this is the first report a ‘Ca. P. australasiaticum’ -related strain associated with Bamboo Witches’ Broom Disease (BWB) in Guangdong, China. The BWB caused by Ca. Phytoplasma (16SrI, 16SrII, 16SrVIII and 16SrXIV group), has been confirmed in several bamboo species in Southeast Asian countries such as India (Yadav et al. 2016; Ravi et al. 2022), Philippines (Dolores et al. 2023), Indonesia (Prasetya et al. 2020) and China (Zhang et al. 2009; Che et al. 2024). This study highlight the need to identify insect vectors and alternative hosts, which will provide theoretical guide to the control of Bamboo Witches’ Broom Disease.

Abstract The critically endangered Caribbean staghorn coral Acropora cervicornis hosts microbiomes frequently dominated by the putatively parasitic intracellular bacterium Candidatus Aquirickettsia rohweri, which is associated with reduced coral growth and heightened disease susceptibility. Whether this dominance can be disrupted through antibiotic treatment and a sequential disturbance of thermal stress, remains unknown. In this study, we exposed disease-susceptible A. cervicornis fragments to broad-spectrum antibiotics, sub-bleaching thermal stress, or the combination of an antibiotic pre-treatment followed by thermal stress, and tracked changes in microbiome composition and diversity across all experimental phases using 16S rRNA amplicon sequencing and quantitative PCR (qPCR). We find that while the minor microbial fraction exhibits sustained compositional shifts in response to treatment, Ca. Aquirickettsia rohweri is resilient to antibiotic and thermal perturbation and may in fact increase in abundance following antibiotic exposure, suggesting that its dominance is actively maintained and not readily displaced by current disease mitigation strategies.These results indicate that antibiotic intervention is unlikely to be a viable strategy for disrupting Ca. A. rohweri dominance in disease-susceptible A. cervicornis , underscoring the urgency of understanding its transmission routes to inform microbiome rescue efforts.