Evaluation of full S1 gene sequencing of classical and variant infectious bronchitis viruses extracted from allantoic fluid and FTA cards.

Evaluation of full S1 gene sequencing of classical and variant infectious bronchitis viruses extracted from allantoic fluid and FTA cards. Avian Pathol. 2018 May 01;:1-21 Authors: Manswr B, Ball C, Forrester A, Chantrey J, Ganapathy K Abstract Sequence variability in the S1 gene determines the genotype of infectious bronchitis virus (IBV) strains. A single RT-PCR assay was developed to amplify and sequence the full S1 gene for six classical and variant IBVs (M41, D274, 793B, IS/885/00, IS/1494/06 and Q1) enriched in allantoic fluid (AF) or the same AF but inoculated onto Flinders Technology Association (FTA) cards. Representative strains from each genotype were grown in SPF eggs and RNA was extracted from AF. Full S1 gene amplification was achieved using primer A and primer 22.51. Products were sequenced using primer A, 1050+, 1380+ and SX3+ to obtain short sequences covering the full gene. Following serial dilutions of AF, detection limits of the partial assay were higher than those of the full S1 gene. Partial S1 sequences exhibited higher than average nucleotide similarity percentages (79%; 352bp) compared to full S1 sequences (77%; 1,756bp), suggesting that full S1 analysis allows greater strain differentiation. For IBV detection from AF inoculated FTA cards, four serotypes were incubated for up to 21 days at three temperatures; 4 oC, 24 oC and 40 oC. RNA was extracted and tested with partial and full S1 protocols. Through partia...
Source: Avian Pathology - Category: Pathology Authors: Tags: Avian Pathol Source Type: research