Effect of Mucin13 gene polymorphism on diarrhoeagenic <i>E. coli</i> adhesion pattern and its expression analysis in native Indian pigs

Abstract

We identified genetic polymorphism in Mucin13 gene affecting E. coli adhesion patterns using (local isolate) diarrhoeagenic E. coli in Indian desi pigs. Five SNPs and one indel previously reported to be associated with enterotoxigenic E. coli (ETEC) F4ab/ac adhesion pattern were examined by designing PCR-RFLP protocol. The genotypic frequencies of only one SNP (g.22304A  >  G) differed significantly (at P ≤ 0.05) in adhesive, non-adhesive and weakly adhesive population. The AA (306 sbp, 231 bp), AG (306, 231, 108, 198 bp) and GG (231, 198 bp, 108 b) genotypes of g.22304A  >  G locus were observed with frequencies 50.0 %, 21.25 % and 28.75 %, respectively and AG genotype was significantly (P ≤ 0.05) associated with a non-adhesive pattern. The polymorphism information content of SNPs ranged from 17.67 (g.22124T  >  C) to 37.36 % (g.21471C  >  T) loci. Three loci (g.21471C  >  T, g.22124T  >  C and g.22304A  >  G) were significantly departed from Hardy–Weinberg equilibrium. The linkage disequilibrium analysis revealed locus g.22124T  >  C and g.22304A  >  G were significantly (P ≤ 0.05) associated with each other. Expression profiling of target gene in jejuna of animals having AA, AG and GG genotypes revealed differences in various genotypes with the highest in the AA, moderate in the GG and low levels in the AG genotype, although they were statistically non-significant (at P ≤ 0.05). The absence of significant effect of genotypes on MUC13 mRNA expression indicates no direct functional role, although the structural role can not be ignored as the putative receptor gene is located within targeted genomic region. Further, reports of same SNP association with an ETEC F4ab/ac adhesion pattern indicate the target gene's role in diarrhoea even caused by other strains of E. coli which is not ETEC.