Full genome characterization of two novel Alpha-coronavirus species from Italian bats

Abstract

Coronaviruses (CoVs) have been detected worldwide in several bat species, which are considered the main reservoir. The attention to the high diversity of CoVs hosted by bats has increased during the last decade due to the high number of human infections caused by two zoonotic Beta-CoVs, SARS-CoV and MERS-CoV, that cause several respiratory diseases. Among coronaviruses, two Alpha-CoV strains (HuCoV-229E and HuCoV-NL63) cause mild respiratory disease that can change to severe disease in children, elderly and individuals affected by illnesses. Phylogenetic analysis conducted on bat Alpha-CoV strains revealed their evolutive correlation to human strains, suggesting their origin in bats. The genome of CoVs is characterized by a high frequency of mutations and recombination events, increasing their ability to switch hosts and their zoonotic potential. In this study, three strains of Alpha-CoV genera detected in Italian bats (Pipistrellus kuhlii) were fully sequenced by Next Generation Sequencing (NGS) and characterized. The complete genome analysis showed the correlation of the Italians strains with a Chinese strain detected in 2013 and, based on CoV molecular species demarcation, two new Alpha-CoV species were established. The analysis of a fragment of the RNA-dependent RNA polymerase (RdRp) showed the correlation of the Italian strains with CoVs that was only detected in the bat Pipistrellus genera (Pipistrellus kuhlii and Pipistrellus Pipistrellus) in European countries.

Keywords: Alpha-CoV viruses; Bats; Full genome sequencing; Italy.

Fig. 1

Maximum phylogenetic tree based on 47 Alpha-CoVs and 12 Beta-CoVs complete genomes. The tree was inferred under the GTR + G + I substitution model and 1000 bootstrap resampling process replications showing values > 70. BatCoV-Ita3, BatCoV-Ita4 and BatCoV-Ita5 are reported in bold and the sequences can be retrieved under accession numbers (MH938448, MH938449, MH938450).