title: Identification of the crp gene in avian Pasteurella multocida and evaluation of the effects of crp deletion on its phenotype, virulence and immunogenicity.
abstract: Pasteurella multocida (P. multocida) is an important veterinary pathogen that can cause severe diseases in a wide range of mammals and birds. The global regulator crp gene has been found to regulate the virulence of some bacteria, and crp mutants have been demonstrated to be effective attenuated vaccines against Salmonella enterica and Yersinia enterocolitica. Here, we first characterized the crp gene in P. multocida, and we report the effects of a crp deletion.
  
  
  
  The P. multocida crp mutant exhibited a similar lipopolysaccharide and outer membrane protein profile but displayed defective growth and serum complement resistance in vitro compared with the parent strain. Furthermore, crp deletion decreased virulence but did not result in full attenuation. The 50 % lethal dose (LD50) of the Δcrp mutant was 85-fold higher than that of the parent strain for intranasal infection. Transcriptome sequencing analysis showed that 92 genes were up-regulated and 94 genes were down-regulated in the absence of the crp gene. Finally, we found that intranasal immunization with the Δcrp mutant triggered both systematic and mucosal antibody responses and conferred 60 % protection against virulent P. multocida challenge in ducks.
  
  
  
  The deletion of the crp gene has an inhibitory effect on bacterial growth and bacterial resistance to serum complement in vitro. The P. multocida crp mutant was attenuated and conferred moderate protection in ducks. This work affords a platform for analyzing the function of crp and aiding the formulation of a novel vaccine against P. multocida.
authors.affiliation: Institute of Preventive Veterinary Medicine, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, 611130, China.|Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Wenjiang, Sichuan, 611130, China.|Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, Wenjiang, Sichuan, 611130, China.
authors.forename: Xinxin
authors.initials: X
authors.lastname: Zhao
authors.affiliation: Department of Bioengineering, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Wenjiang, 611130, China. qing.liu.2@sicau.edu.cn.
authors.forename: Qing
authors.initials: Q
authors.lastname: Liu
authors.affiliation: Institute of Preventive Veterinary Medicine, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, 611130, China.
authors.forename: Kangpeng
authors.initials: K
authors.lastname: Xiao
authors.affiliation: Institute of Preventive Veterinary Medicine, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, 611130, China.
authors.forename: Yunlong
authors.initials: Y
authors.lastname: Hu
authors.affiliation: Institute of Preventive Veterinary Medicine, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, 611130, China.
authors.forename: Xueyan
authors.initials: X
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, China.
authors.forename: Yanyan
authors.initials: Y
authors.lastname: Li
authors.affiliation: Institute of Preventive Veterinary Medicine, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, 611130, China. kongqiki@163.com.|Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Wenjiang, Sichuan, 611130, China. kongqiki@163.com.|Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, Wenjiang, Sichuan, 611130, China. kongqiki@163.com.
authors.forename: Qingke
authors.initials: Q
authors.lastname: Kong
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics* / Q000276:immunology; D001715:Bird Diseases / Q000382:microbiology*; D004372:Ducks; D017353:Gene Deletion; D010326:Pasteurella Infections / Q000382:microbiology / Q000662:veterinary*; D016979:Pasteurella multocida / Q000235:genetics / Q000254:growth & development / Q000276:immunology* / Q000472:pathogenicity*; D010641:Phenotype; D011201:Poultry Diseases / Q000382:microbiology*; D017384:Sequence Deletion; D014774:Virulence
chemical_list: D001426:Bacterial Proteins
keywords: Pasteurella multocida; Regulated genes; Vaccine; Virulence; crp