Molecular detection and differentiation of Mycoplasma gallisepticum field isolates of poultry in Andhra Pradesh

A total of 228 pooled Cloacal swabs, 228 pooled nasal swabs, 228 pooled tracheal swabs samples from the ailing birds and 152 pooled tracheal tissues, 152 pooled lung tissues and 76 pooled oviduct samples from the dead birds were collected from the 19 suspected poultry farms in A.P. and were labelled farm wise and specimen wise. The DNA was extracted from the samples by using Trizol method. The PCR test was standardized by targeting mgc2 gene. The Sequence similarity and variations of newly sequenced isolates of Mycoplasma gallisepticum (MG) i.e. MG VLP, MG7G, MG9G, MG12G and vaccine isolates were compared with the available mgc2 for MG from Gene Bank (NCBI) using multiple sequence alignment software MEGA 10 and Bio edit programs. Analysis of MG field isolates showed 42.71 to 100 per cent similarity. The MG field isolates showed variations between 41^st to 757^th nucleotide positions and insertions at -610T, -611C, -622G, -631A, -632C, -633A and -734A positions and these variations reflected the variations in amino acids between 22^nd to 257^th positions. The Phylogenetic analysis revealed that the vaccine strain (MG5G) and two field strains MG9G, MG7G formed one cluster and these isolates were closely related. The MG5G vaccine strain and two field isolates (MG9G and MG7G) were closely related with Telangana isolates. The MGVLP and MG12G formed one cluster and they are closely related with the UFMG2/Brazil strain and S6Mgc2/Australian strain.