First full length sequences of the S gene of European isolates reveal further diversity among turkey coronaviruses.

Stéphan Maurel (1) , Didier Toquin (1) , François-Xavier Briand (1) , Maryline Queguiner (1) , Chantal Allee (1) , Joel Bertin (2) , Charlotte Retaux (2) , Vincent Turblin (3, 4) , Hervé Morvan (5) , Nicolas Eterradossi (1)

1 VIPAC - Virologie, Immunologie, Parasitologie Avaires et Cunicoles
2 Coopérative Le Gouessant [Lamballe]
3 MC Vet Conseil
4 present adress: Ceva Animal Health
5 Laboratoire de Développement et d'analyse des Côtes d'Armor

An increasing incidence of enteric disorders clinically evocative of the poult enteritis complex has been observed in turkeys in France since 2003. Using a newly designed real-time RT-PCR assay specific for the nucleocapsid (N) gene of infectious bronchitis virus (IBV) and turkey coronaviruses (TCoV), coronaviruses were identified in 37 % of the intestinal samples collected from diseased turkey flocks. The full length Spike (S) gene of these viruses was amplified, cloned and sequenced from three samples. The French S sequences shared 98 % at both the nt and aa levels, whereas they were at most 65 and 60 % identical with North American (NA) TCoV and at most 50 and 37 % identical with IBV at the nt and aa levels, respectively. Higher divergence with NA TCoV was observed in the S1-encoding domain. Phylogenetic analysis based on the S gene revealed that the newly detected viruses form a sublineage genetically related with, but significantly different from, NA TCoV. Additionally, the RNA dependent RNA polymerase (RdRp) and the N genes, located on the 5' and 3' sides of the S gene in the coronavirus genome, were partially sequenced. Phylogenetic analysis revealed that both the NA TCoV and French TCoV (Fr TCoV) lineages included some IBV relatives, which were however different in the two lineages. This suggested that different recombination events could have played a role in the evolution of the NA and Fr TCoV. The present results are the first S sequence for a European TCoV. They reveal extensive genetic variation in TCoV and suggest different evolution pathways in North America and Europe.

Mots clés: Life Sciences

Domaines: Biologie animale

Stéphan Maurel, Didier Toquin, François-Xavier Briand, Maryline Queguiner, Chantal Allee, et al.. First full length sequences of the S gene of European isolates reveal further diversity among turkey coronaviruses.. Avian Pathology, 2011, 40 (02), pp.179-189. ⟨10.1080/03079457.2011.551936⟩. ⟨hal-00687805⟩