Porcine epidemic diarrhea virus (PEDV) is the cause of an economically important swine disease. Previous studies suggested that PEDV does not elicit a robust IFN response, but the mechanism(s) used to evade or block this innate immune response was not known. In this study, we found that PEDV infection blocked synthetic dsRNA-induced IFN-b production by interfering with the activation of interferon regulatory factor 3 (IRF3). We identified PEDV replicase encoded papain-like protease 2 (PLP2) as an IFN antagonist that depends on catalytic activity for its function. We show that levels of ubiquitinated proteins are reduced during PEDV infection and that PEDV PLP2 has deubiquitinase (DUB) activity that recognizes and processes both K-48 and K-63 linked polyubiquitin chains. Furthermore, we found that PEDV PLP2 strongly inhibits RIG-Iand STING-activated IFN expression and that PEDV PLP2 can be co-immunoprecipitated with and deubiquitinates RIG-I and STING, the key components of the signalling pathway for IFN expression. These results show that PEDV infection suppresses production of IFN-b and provides evidence indicating that the PEDV papain-like protease 2 acts as a viral DUB to interfere with the RIG-I-and STING-mediated signalling pathway.

Coronavirus-like viruses, designated peafowl/China/LKQ3/2003 (pf/CH/LKQ3/03) and teal/China/LDT3/2003 (tl/CH/LDT3/03), were isolated from a peafowl and a teal during virological surveillance in Guangdong province, China. Partial genomic sequence analysis showed that these isolates had the S-3-M-5-N gene order that is typical of avian coronaviruses. The spike, membrane and nucleocapsid protein genes of pf/CH/LKQ3/03 had >99 % identity to those of the avian infectious bronchitis coronavirus H120 vaccine strain (Massachusetts serotype) and other Massachusetts serotype isolates. Furthermore, when pf/CH/LKQ3/03 was inoculated experimentally into chickens (specific-pathogen-free), no disease signs were apparent. tl/CH/LDT3/03 had a spike protein gene with 95 % identity to that of a Chinese infectious bronchitis virus (IBV) isolate, although more extensive sequencing revealed the possibility that this strain may have undergone recombination. When inoculated into chickens, tl/CH/LDT3/03 resulted in the death of birds from nephritis. Taken together, this information suggests that pf/CH/LKQ3/03 might be a revertant, attenuated vaccine IBV strain, whereas tl/CH/LDT3/03 is a nephropathogenic field IBV strain, generated through recombination. The replication and non-pathogenic nature of IBV in domestic peafowl and teal under field conditions raises questions as to the role of these hosts as carriers of IBV and the potential that they may have to transmit virus to susceptible chicken populations. INTRODUCTIONCoronaviruses (family Coronaviridae) belong to the order Nidovirales and contain a positive-stranded RNA genome that ranges from 27 to 31 kb in size (Cavanagh, 1997). Members of the family Coronaviridae infect a wide range of hosts and have been classified into three groups on the basis of antigenicity, genome organization and sequence similarity. Usually, coronaviruses infect only their normal target host species. It has, however, been reported that some strains of canine coronavirus and human coronavirus 229E can infect other, non-target species without causing disease (Barlough et al., 1984(Barlough et al., , 1985. The recent emergence of severe acute respiratory syndrome coronavirus (SARSCoV), which has been classified tentatively into group 2, has focused a great deal of interest on this virus family (Holmes, 2003). It was reported that SARS-CoV-like viruses were isolated from Himalayan palm civets (Guan et al., 2003) and ferrets (Mustela furo). Moreover, domestic cats (Felis domesticus) are susceptible to infection by SARSCoV, suggesting that the reservoir for this pathogen might involve a range of animal species (Martina et al., 2003).Infectious bronchitis virus (IBV), together with genetically related coronaviruses of turkey and pheasant, belongs to the group 3 coronaviruses. IBV is a pleomorphic, enveloped virus with club-shaped surface projections (spikes) and a single-stranded, positive-sense RNA genome of >27 kb in length (Boursnell et al., 1987). Upon virus entry into cells, a 39-coterminal nested set of six ...

Porcine epidemic diarrhea (PED) is an intestinal infectious disease caused by porcine epidemic diarrhea virus (PEDV); manifestations of the disease are diarrhea, vomiting and dehydration. Starting from the end of 2010, a PED outbreak occurred in several pig-producing provinces in southern China. Subsequently, the disease spread throughout the country and caused enormous economic losses to the pork industry. Accumulating studies demonstrated that new PEDV variants that appeared in China were responsible for the PED outbreak. In the current mini-review, we summarize PEDV epidemiology and vaccination in China.

Domestic sheep and their wild relatives harbor substantial genetic variants that can form the backbone of molecular breeding, but their genome landscapes remain understudied. Here, we present a comprehensive genome resource for wild ovine species, landraces and improved breeds of domestic sheep, comprising high-coverage (∼16.10×) whole-genomes of 810 samples from 7 wild species and 158 diverse domestic populations. We detected, in total, ∼121.2 million single nucleotide polymorphisms (SNPs), ∼61 million of which are novel. Some display significant (P < 0.001) differences in frequency between wild and domestic species, or are private to continent-wide or individual sheep populations. Retained or introgressed wild gene variants in domestic populations have contributed to local adaptation, such as the variation in the HBB associated with plateau adaptation. We identified novel and previously reported targets of selection on morphological and agronomic traits such as stature, horn, tail configuration and wool fineness. We explored the genetic basis of wool fineness and unveiled a novel mutation (chr25: T7068586C) in the 3’-UTR of IRF2BP2 as plausible causal variant for fleece fiber diameter. We reconstructed pre-historical migrations from the Near Eastern domestication center to South-and-Southeast Asia, and found two main waves of migrations across the Eurasian Steppe and the Iranian Plateau in the Early and Late Bronze Ages. Our findings refine our understanding of genome variation as shaped by continental migrations, introgression, adaptation and selection of sheep.