Transcriptomic analysis of caecal tissue in inbred chicken lines that exhibit heritable differences in resistance to Campylobacter jejuni

Abstract

Background Campylobacter jejuni is the leading cause of bacterial gastroenteritis in humans and the handling or consumption of contaminated poultry meat is a key source of infection. Selective breeding of poultry that exhibit elevated resistance to Campylobacter is an attractive control strategy. Here we studied the global transcriptional response of inbred chicken lines that differ in resistance to C. jejuni colonisation at a key site of bacterial persistence. Results Three-week-old chickens of line 61 and N were inoculated orally with C. jejuni strain M1 and caecal contents and tonsils were sampled at 1 and 5 days post-infection. Caecal colonisation was significantly lower in line 61 compared to line N at 1 day post-infection, but not 5 days post-infection. RNA-Seq analysis of caecal tonsils of both lines revealed a limited response to C. jejuni infection compared to age-matched uninfected controls. In line N at days 1 and 5 post-infection, just 8 and 3 differentially expressed genes (DEGs) were detected (fold-change > 2 and false-discovery rate of < 0.05) relative to uninfected controls, respectively. In the relatively resistant line 61, a broader response to C. jejuni was observed, with 69 DEGs relating to immune regulation, cell signalling and metabolism at 1 day post-infection. However, by day 5 post-infection, no DEGs were detected. By far, the greatest number of DEGs were between uninfected birds of the two lines implying that differential resistance to C. jejuni is intrinsic. Of these genes, several Major Histocompatibility Complex class I-related genes (MHCIA1, MHCBL2 and MHCIY) and antimicrobial peptides (MUC2, AvBD10 and GZMA) were expressed to a greater extent in line N. Two genes within quantitative trait loci associated with C. jejuni colonisation were also more highly expressed in line N (ASIC4 and BZFP2). Quantitative reverse-transcriptase PCR analysis of a subset of transcripts confirmed the RNA-Seq results. Conclusions Our data indicate a limited transcriptional response in the caecal tonsils of inbred chickens to intestinal colonisation by Campylobacter but identify a large number of differentially transcribed genes between lines 61 and N that may underlie variation in heritable resistance to C. jejuni.

Genetic resistance to Campylobacter coli and Campylobacter jejuni in wild boar (Sus scrofa L.)

“…Genetic resistance to microbial diseases has only been partially explored. The genetic determinants for resistance to Campylobacter infections in poultry have been the subject of various studies, especially regarding resistance to C. jejuni (Calenge and Beaumont 2012;Psifidi et al 2021;Russell et al 2021). Regarding suids, microbial disease resistance genes have been studied in pigs focusing on Gram-negative bacilli (Zhao et al 2012); however to the best of our knowledge, our study is one of the first attempts to identify genomic regions associated with infection by C. coli and C. jejuni in wild boars.…”

Comparative analysis of the caecal tonsil transcriptome in two hen lines experimentally infected withSalmonellaEnteritidis

“…The impact of host genetic variations was considered in a recent study of the caecal tissue transcriptome after Campylobacter colonisation. Comparisons between the experimental White Leghorn inbred chicken lines 6 1 and N led to the identification of a large number of differentially expressed genes, which may underlie variation in heritable resistance to the pathogen [12]. The host genetic background is an important factor for the outcome of Salmonella infection in chicken.…”