Conference Agenda
Overview and details of the sessions of this conference. Please select a date or location to show only sessions at that day or location. Please select a single session for detailed view (with abstracts and downloads if available).
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Daily Overview |
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CP21: Cells, Molecules & Genes 4 - 15 min talks
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The chromosome-scale assembly of the Australian Paralysis Tick, Ixodes holocyclus 1Walter and Eliza Hall Institute, Department of Medical Biology, The University of Melbourne, Victoria, Australia; 2Zoonotic & Arboviral pathogens, Health & Biosecurity, CSIRO, Canberra, Australia; 3Olivia Newton-John Cancer Research Institute, Australia; 4Department of Veterinary Biosciences, Melbourne Veterinary School, Faculty of Science, The University of Melbourne, Victoria, Australia; 5Icahn School of Medicine at Mount Sinai, USA; 6Microbiology and Virology unit at Policlinico San Matteo, Fondazione IRCCS, Pavia, Province of Pavia, Italy; 7The University of Queensland, Queensland Alliance for Agriculture & Food Innovation, St Lucia, Queensland, Australia; 8School of Life and Environmental Sciences, The University of Sydney, New South Wales; 9School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland, Australia; 10Department for Chemistry, Institute for Biochemistry, University of Cologne, Cologne, Germany; 11Deceased:Fabrizia Stavru; 12Department of Biology and Biotechnology, University of Pavia, Pavia, Italy; 13Fondazione IRCCS Policlinico San Matteo, Pavia, Italy Ixodes holocyclus (the Australian eastern paralysis tick) is a medically and veterinary important ectoparasite that produces potent neurotoxins, holocyclotoxins, causing rapidly ascending flaccid paralysis in companion animals, livestock and humans, often fatally. Despite its importance, the molecular basis of toxin production, host specificity and survival remains poorly understood because genomic and transcriptomic resources are limited. We generated the first chromosomal-scale genome for I. holocyclus using Oxford Nanopore long reads, Illumina short reads and Hi-C, and annotated genes with a hybrid de novo transcriptome, resolving alternative splicing with long- and short-read alignments. We scanned UTRs and upstream regions of complete genes for conserved regulatory motifs, including putative promoters. Comparative genomics, including synteny and phylogenomic placement, was performed, and ticks from 32 eastern Australian sites were sequenced to examine genomic diversity and its links to ecological adaptation and vector capacity. The 1.9 Gb assembly contains 13 chromosome-level scaffolds, 66% repetitive elements and 93.3% BUSCO completeness. Annotation identified a high-confidence gene set including protein-coding genes. Synteny with I. scapularis and I. ricinus revealed conserved supergene blocks. Together, these resources advance tick biology and support targeted control strategies against tick-borne diseases. Long-read–supported gene modelling illuminates feeding, immune, and developmental biology in the European castor bean tick, Ixodes ricinus. 1Walter and Eliza Hall Institute, Department of Medical Biology, The University of Melbourne, Victoria, Australia; 2Department of Microbiology & Virology, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy; 3Olivia Newton-John Cancer Research Institute, Victoria, Australia; 4CSIRO, Health and Biosecurity, Brisbane, Queensland, Australia; 5Department of Veterinary Medicine and Animal Sciences, University of Milan, Lodi, Italy; 6The University of Queensland, Queensland Alliance for Agriculture & Food Innovation, St Lucia, Queensland, Australia; 7School of Life and Environmental Sciences, The University of Sydney, New South Wales; 8Oniris, INRAE, BIOEPAR, 44300, Nantes, France; 9Department for Chemistry, Institute for Biochemistry, University of Cologne, Cologne, Germany; 10Deceased: Fabrizia Stavru; 11Department of Veterinary Biosciences, Melbourne Veterinary School, Faculty of Science, The University of Melbourne, Victoria, Australia; 12Department of Biology and Biotechnology, University of Pavia, Pavia, Italy; 13Fondazione IRCCS Policlinico San Matteo, Pavia, Italy The European castor bean tick, Ixodes ricinus, is a major blood-feeding ectoparasite and vector of Lyme disease, tick-borne encephalitis and babesiosis. Reducing tick-borne disease requires an improved understanding of tick molecular biology across tissues and feeding stages. We applied long-read, full-length mRNA sequencing to refine gene models in the published I. ricinus genome and to profile salivary glands and ovaries across blood-feeding phases. Curated functional annotation was used to interpret pathways central to ectoparasitism. We defined 30,454 gene models, including 28,515 protein-coding genes. Functional curation provided insight into chemosensation, hematophagy, immune tolerance, reproduction and fecundity. Salivary glands showed feeding-associated metabolic rewiring, vesicle biogenesis, and secretome remodelling, consistent with anti-clotting, vasodilatory, anti-inflammatory, and immunomodulatory functions that counter host defences. Ovarian transcriptomes revealed early reprogramming of cell-fate pathways, cytoskeletal organisation, extracellular matrix dynamics, and immune regulation, consistent with priming for fertilisation and embryogenesis. This transcriptomic blueprint provides a high-resolution annotation resource for the I. ricinus genome and delineates tissue- and stage-specific programmes that underpin feeding and reproduction, providing a platform for mechanistic studies and improved tick control strategies. | ||