In order to understand the epidemic status and genetic variation of porcine epidemic diarrhea virus(PEDV)in Fujian Province from 2016 to 2022,231 samples of piglets suspected of PED disease were collected from Fujian Province.PEDV genome was detected by RT-PCR,afterwards,22 PEDV-positive samples were selected for PCR amplification and sequencing of S gene.MegAlign was used to analyze the similarity of PEDV S gene sequences and its encoded amino acid sequences.MEGA7.0 software was used to construct phylogenetic tree.MegAlign was then used for the recombination analysis,and BEAST software was used to estimate the divergence time.The results showed that the total positive rate of PEDV in Fujian was 51.51％(119/231),and the positive rates of PEDV in 5 different regions of Fujian ranged from 40.00％to 63.16％.19 PEDV S gene sequences were obtained from 22 positive samples.The total length of PEDV S gene sequences was 4149bp-4161bp,encoding a total of 1382-1386 amino acids.The similarity between the PEDV S gene sequences and their encoded amino acid sequences was 94.4％-100％and 93.8％-100％,respectively.Phylogenetic analysis of 19 PEDV S genes showed that 18 PEDV strains belonged to GⅡb subtype and 1 to GⅠb subtype.Amino acid sequence analysis of S protein showed that compared with the classic vaccine strain CV777,18 GⅡb subtype PEDV S fragments had insertion or deletion at three loci of aa55-aa56,aa135-aa136 and aa155-aa156,showing the molecular characteristics of typical PEDV variants.Compared with GⅡ vaccine strain AJ1102,the amino acid mutation rate in S1 region of 19 PEDV strains ranged from 60.00％-83.82％,among which 10 amino acid mutation sites were located in the key domain of S protein.The results of gene recombination showed that three PEDV S genes were recombinant,among which FJLY01-2018 was originated from GD-B strain and CH-S strain,while FJLY02-2018 was recombined from CH/HNPJ/2017 strain and PEDV4-S-3 strain.FJLY03-2022 was derived from PEDV-1931-1-Valladolid-Molpeceres strain and HUA-M17 strain.The results of divergence time estimation showed that the earliest divergence time of the GⅡa subtype,GⅡb subtype,GⅠa subtype and GⅠb subtype PEDV in Fujian was about in 1995,2009,2010 and 2011,respectively.The above results indicated that the detection rate of PEDV in Fujian is relatively high,and the genotypes of endemic strains in the field are diverse and recombination exists,which should be paid great attention.This study provides a reference for the epidemiological investigation and immunization prevention and control of porcine epidemic diarrhea in Fujian Province.
porcine epidemic diarrhea virusS genegenetic variationgene recombinationdivergence times
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