A novel coronavirus strain was isolated from laryngotracheal swab of wild partridge and designated as partridge/GD/S14/2003 (S14) . Its whole genomic sequence was obtained (Gen. Bank Accession number: AY646283) through RT-PCR amplification, cloning, nucleotide sequencing, and analysis by the DNASTAR program. To investigate the origin of the virus, we further analyzed the nucleotide sequences of the main structural proteins, and compared those with other available virus isolates. Our results showed that the highest nucleotide homologies between the S1 gene of S14 strain and those of nephrogenic-type strains JX1-99 and TJ2-96 were 94.6% and 93.4%, respectively. In addition, a relatively high genetic identity 85% and 84.3% respectively was detected between S1 gene of S14 and those of strains QXIBV and LX4. The results suggested that the S14 strain may be originated from or related to nephrogenic-type and proventriculus-type infectious bronchitis virus IBV . The highest nucleotide homology between the S2 gene of S14 strain and those of QXIBV and LX4 was 85% and 84.3% respectively and all of them belonged to group II coronaviruses. The highest nucleotide homology between the M gene of S14 strain and those of strains SAIB20 and GD6-98 was 90.6% and 90.2% respectively by which S14 belonged to group III. Although they displayed high level of genetic identity in SI and S2 gene there was lower homology of M coding sequences between S14 and BJ and between S14 and QXIBV strains. Phylogenetic analysis of N gene indicated that group I strains might evolve from RNA recombination between strain H52 and Gray while group II strains from strain H120 and D1466. S14 strain had the highest N gene homology with strain QXIBV which was 95. 7% thus classified as a group III member. Strains SAIB20 and GD6-98 which were closely related to the M gene of S14 strain belonged to group I and IV respectively. A possible role of partridge S14 strain may play in the process of coronavirus evolution is discussed.
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