title: Transcriptional profiles of virulent and precocious strains of Eimeria tenella at sporozoite stage; novel biological insight into attenuated asexual development.
abstract: Chicken coccidiosis is caused by Eimeria spp., particularly Eimeria tenella, and is characterized by watery or hemorrhagic diarrhea, resulting in death in severe cases. Precociously attenuated live vaccines are widely used to control the disease, and these are produced by serially passaging virulent strains through chickens, and the collection of oocysts from feces at progressively earlier time points during oocyst shedding. Sporozoites of the precocious strain rapidly enter the intestinal mucosa, and their subsequent asexual development reduces their growth. However, there have been few detailed genetic or transcriptional analyses of the strains. Here, we used RNA sequencing to gain novel biological insight into the pathogenicity and precocity of E. tenella. We compared the differential transcription in the sporozoites (the initial stage of endogenous development) of virulent and precocious strains by mapping the sequence reads onto the draft genome of E. tenella. About 90% of the reads from both strains were mapped to the genome, and 16,630 estimated transcript regions were identified. Using Gene Ontology slim and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses and the annotation of the estimated transcripts with Blastx, we found that the expression of some genes involved in carbohydrate metabolism were expressed two-fold more strongly in the virulent strain than in the precocious strain. Characteristically, genes related to proteins secreted from the apical complex, proteases, cell attachment proteins, mitochondrial proteins, and transporters were most strongly upregulated in the virulent strain. Interestingly, the expression of genes associated with cell survival, development, or proliferation was strongly upregulated in the precocious strain. These findings suggest that virulent strains survive long before invasion and invade actively/successfully into host cells, whereas proliferative processes appear to affect precocity.
authors.affiliation: National Institute of Animal Health, National Agricultural and Food Research Organization, 3-1-5 Kannondai, Tsukuba, Ibaraki 305-0856, Japan; Division of Veterinary Science, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-58 Rinku Orai Kita, Izumisano, Osaka 598-8531, Japan. Electronic address: matsubayashi@vet.osakafu-u.ac.jp.
authors.forename: Makoto
authors.initials: M
authors.lastname: Matsubayashi
authors.affiliation: Nippon Institute for Biological Science, 9-2221-1 Shin-machi, Ome, Tokyo 198-0024, Japan.
authors.forename: Fumiya
authors.initials: F
authors.lastname: Kawahara
authors.affiliation: National Institute of Animal Health, National Agricultural and Food Research Organization, 3-1-5 Kannondai, Tsukuba, Ibaraki 305-0856, Japan; Department of Parasitology, Kitasato University School of Medicine, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa 252-0374, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Hatta
authors.affiliation: Tohoku Medical Megabank Organization, Tohoku University, 6-3-09 Aramaki Aza Aoba, Aoba-ku, Sendai, Miyagi 980-8579, Japan; Division of Collaboration and Education, Research Center for Zoonosis Control, Hokkaido University, North 20, West 10 Kita-ku, Sapporo, Hokkaido 001-0020, Japan; Global Station for Zoonosis Control, GI-CoRE, Hokkaido University, North 20, West 10 Kita-ku, Sapporo, Hokkaido 001-0020, Japan.
authors.forename: Junya
authors.initials: J
authors.lastname: Yamagishi
authors.affiliation: National Institute of Animal Health, National Agricultural and Food Research Organization, 3-1-5 Kannondai, Tsukuba, Ibaraki 305-0856, Japan.
authors.forename: Takeharu
authors.initials: T
authors.lastname: Miyoshi
authors.affiliation: National Institute of Animal Health, National Agricultural and Food Research Organization, 3-1-5 Kannondai, Tsukuba, Ibaraki 305-0856, Japan.
authors.lastname: Anisuzzaman
authors.affiliation: Division of Veterinary Science, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-58 Rinku Orai Kita, Izumisano, Osaka 598-8531, Japan.
authors.forename: Kazumi
authors.initials: K
authors.lastname: Sasai
authors.affiliation: National Institute of Animal Health, National Agricultural and Food Research Organization, 3-1-5 Kannondai, Tsukuba, Ibaraki 305-0856, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Isobe
authors.affiliation: Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Kita
authors.affiliation: Department of Parasitology, Kitasato University School of Medicine, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa 252-0374, Japan. Electronic address: tsujin@med.kitasato-u.ac.jp.
authors.forename: Naotoshi
authors.initials: N
authors.lastname: Tsuji
mesh_terms: D000818:Animals; D002645:Chickens; D003048:Coccidiosis / Q000662:veterinary; D016786:Eimeria tenella / Q000235:genetics / Q000254:growth & development* / Q000472:pathogenicity; D020869:Gene Expression Profiling / Q000379:methods*; D005786:Gene Expression Regulation; D063990:Gene Ontology; D011201:Poultry Diseases / Q000469:parasitology; D017423:Sequence Analysis, RNA / Q000379:methods*; D034101:Sporozoites / Q000502:physiology; D037521:Virulence Factors / Q000235:genetics*
chemical_list: D037521:Virulence Factors
keywords: Eimeria tenella; Precocious strain; RNA sequencing; Sporozoites; Virulent strain