Analysis Of Correlation Between Adhesion Phenotype Of Escherichia Coli F18 And Genotype Of FUT1 Gene On Porcine

Porcine postweaning diarrhea and oedema disease are still responsible for considerable economic losses, and E.coli is a common porcine enteric pathogen. Researchers have recognized that pathogenic E.coli includes Enteropathogenic Escherichia coli, Enterotoxigenic Escherichia coli, Verotoxigenic Escherichia coli, Enteroinvasive Escherichia coli, Enterohemorrhagic Escherichia coli and Enteroaggregative Escherichia coli.E.coli fimbriae F18 has two variants, that is F18ab and F18ac, and they are the most important factors causing postweaning diarrhea and oedema disease. They adhere to the brush border of enterocytes, so that they can withstand creepage of intestine and scour of liquid in intestine, then release enterotoxin and histamine by osmosis, and finally cause disease. Whether they can adhere to the the brush border of enterocytes or not depends on the existence of their receptors. The gene encoding the E.coli F18 receptor (ECF18R) has been mapped on the porcine chromosome 6, and the FUT1 gene which was localized on SSC6q11 has been recognized as the best candidate gene for ECF18R.In order to confirm the correlation between F18 adhesion and FUT1gene M307 polymorphism further, an in vitro adhesion assay was carried out for two variants of E.coli F18 (ab and ac) in 363 piglets came from three pig breeds (Landrance, Large White and Songliao Black), and a polymorphism test in 447 individuals including parendts and their offsprings. Association analysis was carried out by SAS software.After studying, we draw the following conclusions:⑴E.coli fimbriae F18ab is easier to be expressed than fimbriae F18ac in vitro; LB is fitting for F18ab expressing , and TSA and TSB for F18ac expressing.⑵With respect to adhesion phenotype distribution, there are no significant difference between three pig breeds (P﹥0.05) within the same fimbriae variant;⑶Adhesion ability of F fimbriae 18ab is stronger than that of fimbriae F18ac .Chi-square test shows that there are significant difference between the adhesion phenotype distributioin of two variants (P﹤0.01);⑷Three adhesion patterns was found, and there are no significant difference between three breeds in adhesion patterns (P﹥0.05);⑸Three different genotypes at the Hin6Ⅰ-RFLP site of FUT1 were detected in all three pig breeds,that is GG, AG and AA, and allele G is the dominant gene. With respect to genotype distribution, there are signifficiant difference between Large White and Songliao Black (P﹤0.01), Large White and Landrace (P﹤0.05), and Landrace and Songliao Black (P﹤0.05);⑹Chi-squre test shows that FUT1 genotype and adhesion phenotype are stistically associated (P﹤0.001).