Publications

4646

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 He.pat.in'co.la. Gr. neut. n. hêpar (gen. hêpatos) , liver; L. masc./fem. n. incola , inhabitant, dweller; N.L. masc. n. Hepatincola , a dweller of the liver. Pseudomonadota / Alphaproteobacteria / Rhodospirilalles / Candidatus Hepatincolaceae / Candidatus Hepatincola Candidatus Hepatincola is a genus of uncultured, obligately host‐associated bacteria originally discovered in the lumen of the midgut glands (hepatopancreas) of terrestrial isopods. In this niche, the bacteria exhibit a characteristic morphology: elongated rods with a stalk‐like appendage at one pole, which can be inserted between the microvilli of the midgut epithelium. All known members of the genus belong to two species ( Ca . Hepatincola porcellionum and a yet to be named Ca . Hepatincola sp.) associated with terrestrial isopods. However, closely related genera from the same family have been observed in numerous aquatic and terrestrial members of the Ecdysozoa (molting invertebrates). Ca . Hepatincola and closely related genera all have reduced genomes of about 1.3 Mb with low DNA G + C content ( c . 30%) and extremely limited biosynthetic capacities but rich in transporters to import essential nutrients and precursors from the environment. In line with its ecological niche (the host gut lumen, a nutrient‐rich environment) and genomic characteristics, Ca . Hepatincola is rather a nutrient scavenger than a nutrient provider for the host. Ca . Hepatincola was initially classified within the order Rickettsiales and later within the Holosporales , but recent phylogenomic analyses support its phylogenetic placement within the order Rhodospirillales . DNA G + C content (mol % ) : 30. Type species : Candidatus Hepatincola porcellionum Wang et al. (2004), CL1.

Abstract A new distribution map is provided for Candidatus Phytoplasma ziziphi Jung et al. Mollicutes: Acholeplasmatales: Acholeplasmataceae. Main host: jujube (Ziziphus jujuba), also other stone fruits.

Abstract A new distribution map is provided for Candidatus Phytoplasma rubi Malembic-Maher et al. Mollicutes: Acholeplasmatales: Acholeplasmataceae. Hosts: Rubus spp.

Abstract Krum.hol.zi.bac.te.ri.o'ta. N.L. neut. n. Krumholzibacterium , type genus of the type class of the phylum; L. neut. pl. n. suff. ‐ota , ending to denote a phylum; N.L. neut. pl. n. Krumholzibacteriota , the phylum of the class Krumholzibacteria. The phylum Candidatus Krumholzibacteriota was proposed to accommodate genomic assemblies of yet‐uncultured microorganisms. The type species, of the genus, Candidatus Krumholzibacterium zodletonense Zgenome0171 T was recovered from an anaerobic, sulfide‐ and sulfur‐rich spring in Southwestern Oklahoma, USA. The phylum comprises one described class, order, family, genus, and species. However, currently available genomes ( n  = 90) in GTDB (release 08‐RS214) are accommodated in 1 class, 6 orders, 8 families, 30 genera, and 58 species. Phylogenetically, the phylum is closely related to Gemmatimonadota and multiple phyla with no cultured representatives ( Ca . Edwardsbacteria, Ca . Eisenbacteria, Ca . Latescibacterota, Ca . Zixibacteria, 4572‐55, ARS69, GCA‐2686955, JAAXHH01, JABDJQ01, JAGLTZ01, JAGLYR01, TA06, TA06_A, and VGIX01); all of which are part of the FCB ( Fibrobacteres , Chlorobia , Bacteroidetes ) superphylum in the Gracilicutes clade. Candidatus Krumholzibacteriota genomes have mainly been recovered from marine, freshwater, engineered, and host‐associated ecosystems. The prevailing in‐situ conditions in sampled habitats, gene content analysis, and the use of predictive machine learning‐based approaches suggest a phylum‐wide preference for anaerobic conditions, mesophilic temperatures, circumneutral pH, and low salinities. Metabolically, the type species of the type genus of the phylum is predicted to be a fermentative anaerobe with preference for amino acids over sugars as substrates. Later studies indicate that some members of the phylum harbor respiratory capacities (dissimilatory sulfate reduction, dissimilatory sulfite reduction, iron‐reduction, and high‐affinity oxygen respiration with a few members possessing the potential for low‐affinity oxygen respiration), while others possess the machinery for anaerobic degradation of aromatic hydrocarbons. Finally, although all members of Candidatus Krumholzibacteriota remain uncultured, a representative of the phylum was enriched in a methane‐ and iron‐fed bioreactor inoculated with Bothnian Sea sediments. Type genus : Candidatus Krumholzibacterium Youssef et al. 2019, CL2.

ABSTRACT Ponkan mandarin ( Citrus reticulata cv. Ponkan) is an important fruit crop planted across different countries. One of its most devastating diseases is citrus huanglongbing (HLB), which is associated with infection by the bacterium Candidatus Liberibacter asiaticus ( C Las). Although studies on HLB in Ponkan mandarin have been conducted, symptom heterogeneity and its association with C Las titer under field conditions remain underexplored. We examined the association between symptom variation and C Las infection status in a Ponkan mandarin grove by categorizing symptoms at both the leaf and canopy (tree) level. Chlorotic leaves were sampled and classified into different categories, including leaves exhibiting interveinal chlorosis (Cat. A), those showing vein yellowing (Cat. B), and blotchy mottled leaves (Cat. C). Polymerase chain reaction (PCR) and quantitative PCR (qPCR) assays targeting C Las revealed that Cat. A leaves, which resembled nutrient-deficient leaves, had higher C Las detection rates and a larger proportion of samples with high C Las titers. Canopy-level assessment of symptom diversity within each tree also revealed that plants bearing Cat. A leaves were more likely to carry C Las and have high pathogen loads. The likelihood was also greater in trees with higher leaf symptom diversity. Additional prophage typing of the detected C Las strains revealed that leaf symptom variations were independent of prophage type difference. Nutrient analyses revealed reduced magnesium, manganese, and zinc contents in Cat. A leaves, indicating that leaves prone to C Las infection also exhibited nutrient deficiencies. These findings highlight the complexity of potential cultivar-specific associations between C Las and citrus under field conditions. IMPORTANCE Although it is well-established that HLB in Ponkan mandarin is associated with C Las infection, the relationship between leaf symptom variation in this cultivar and the presence and titer of C Las under complex field conditions remains unclear. By examining symptom heterogeneity in natural field conditions at both the leaf and canopy level, this study demonstrated that HLB leaf symptom variation in naturally infected Ponkan mandarin corresponds to differences in C Las presence and titer at both levels. Notably, although blotchy mottling is considered the typical leaf symptom of HLB, we found that C Las detection rates and titers tended to be greater in leaves showing nutrient deficiency-like symptoms, which contrasts with patterns in other citrus cultivars. Recognizing inconsistencies among cultivar-specific patterns is important for interpreting HLB symptoms, devising sampling strategies, and exploring uncharacterized factors affecting symptom expression under field conditions.