In Brazil 'Candidatus Liberibacter asiaticus' and 'Ca. L. americanus' cause huanglongbing (also known as greening), the most destructive citrus disease. A shift in pathogen prevalence was observed over time, with a disproportional increase in 'Ca. L. asiaticus' occurrence. Graft transmission experiments were used for a comparative study of both species using budsticks from symptomatic branches of field-affected trees as inoculum. The plants were inoculated with 'Ca. L. asiaticus' or 'Ca. L. americanus' alone, or simultaneously with both species. Symptom manifestation and conventional and quantitative real-time polymerase chain reaction were used for plant evaluations. 'Ca. L. americanus' was detected mainly in symptomatic plants and 'Ca. L. asiaticus' was detected in symptomatic plants as well as in infected plants prior to symptom manifestation. Transmission percentages varied from 54.7 to 88.0% for 'Ca. L. asiaticus' and 10.0 to 45.2% for 'Ca. L. americanus' in two experiments. In co-inoculated plants, 12.9% contained 'Ca. L. americanus' only, 40.3% contained 'Ca. L. asiaticus' only, and 19.3% contained both species. Average bacterial titers for 'Ca. L. asiaticus' and 'Ca. L. americanus', in log cells per gram of leaf midrib, were 6.42 and 4.87 for the experimental plants and 6.67 and 5.74 for the field trees used as the source of inoculum. The higher bacterial populations of the 'Ca. L. asiaticus'-infected plants provided an explanation for the disproportional increase in field prevalence of this species over time, based on the greater likelihood for pathogen transmission by the insect vector.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1094/PHYTO-99-3-0301 | DOI Listing |
Vet Parasitol Reg Stud Reports
November 2024
Warnell School of Forestry and Natural Resources, 180 E Green Street, University of Georgia, Athens, GA 30602, USA; Southeastern Cooperative Wildlife Disease Study, 589 D.W. Brooks Drive, Wildlife Health Building, College of Veterinary Medicine, The University of Georgia, Athens, GA 30602, USA; Center for the Ecology of Infectious Diseases, University of Georgia, Athens, GA 30602, USA. Electronic address:
Trypanosoma cruzi is an important cause of disease and death in humans and dogs, and although wildlife infections are common, less is known about disease manifestations. A 12-week-old male American black bear (Ursus americanus) cub with mild lethargy and anorexia presented to a wildlife rehabilitation center in Lake Tahoe, California. The cub continued to become increasingly weak and showed decreasing interest in play and other activities.
View Article and Find Full Text PDFComp Biochem Physiol A Mol Integr Physiol
January 2025
Institut des sciences de la mer de Rimouski, Université du Québec à Rimouski, Rimouski, QC G5L 3A1, Canada. Electronic address:
Winter flounder (Pseudopleuronectes americanus) is a North Atlantic flatfish that inhabits cold-water environments already affected by global warming. Flatfishes are particularly sensitive during their juvenile stage to a phenomenon known as temperature-dependent sex determination (TSD). In this study, we hypothesized that many genes involved in the steroidogenesis pathway are already expressed at the larval stage in winter flounder and that temperature conditions may influence this pathway prior to the juvenile stage, which is usually considered the TSD-sensitive period.
View Article and Find Full Text PDFOecologia
December 2024
Département de Biologie and Centre d'Études Nordiques, Université Laval, Québec, QC, Canada.
Climate change disproportionately affects northern and alpine environments, with faster rates of warming than the global average. Because alpine and northern species are particularly well adapted to cool temperatures, most species must modify their behavior when temperatures exceed a critical threshold. Evaluating how temperature increases affect species inhabiting northern and alpine environments is therefore essential to understand the effects of projected climate change on these ecosystems.
View Article and Find Full Text PDFAdv Parasitol
October 2024
Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA, United States; Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA, United States. Electronic address:
Parasitic nematodes infect over 2 billion individuals worldwide, primarily in low-resource areas, and are responsible for several chronic and potentially deadly diseases. Throughout their life cycle, these parasites are thought to use astacin metalloproteases, a subfamily of zinc-containing metalloendopeptidases, for processes such as skin penetration, molting, and tissue migration. Here, we review the known functions of astacins in human-infective, soil-transmitted parasitic nematodes - including the hookworms Necator americanus and Ancylostoma duodenale, the threadworm Strongyloides stercoralis, the giant roundworm Ascaris lumbricoides, and the whipworm Trichuris trichiura - as well as the human-infective, vector-borne filarial nematodes Wuchereria bancrofti, Onchocerca volvulus, and Brugia malayi.
View Article and Find Full Text PDFPlant Dis
October 2024
Fundecitrus, Pesquisa & Desenvolvimento, Araraquara, SP, Brazil.
The occurrence of 'Candidatus Liberibacter' spp. and '. Phytoplasma' spp.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!