Plant & Animal Genomes XVI Conference

January 12-16, 2008
Town & Country Convention Center
San Diego, CA

Microarray Analysis Of Gene Expression In The Blue Catfish Liver Reveals Early Activation Of The MHC Class I Pathway After Infection With Edwardsiella ictaluri

Eric Peatman , Jason Abernathy , Jeffery Terhune , Puttharat Baoprasertkul , Peng Xu , Samiran Nandi , Shaolin Wang , Benjaporn Somridhivej , Huseyin Kucuktas , Ping Li , Rex Dunham , Zhanjiang (John) Liu

  The FISH Molecular Genetics and Biotechnology Laboratory, Department of Fisheries and Allied Aquacultures and Program of Cell and Molecular Biosciences, Aquatic Genomics Unit, Auburn University, Auburn, AL 36849, USA

Catfish is the predominant aquaculture species in the United States. However, transcriptomic-level studies of disease-related gene expression and immune responses to pathogen infections are limited. Here, we have developed and utilized a 28K in situ oligonucleotide microarray composed of blue catfish (Ictalurus furcatus) and channel catfish (I. punctatus) transcripts. While channel catfish accounts for the majority of commercial production, the closely related blue catfish possesses several economically important traits. In particular, blue catfish is highly resistant to the major bacterial disease enteric septicemia of catfish (ESC) caused by the Gram negative bacterium Edwardsiella ictaluri whereas channel catfish is highly susceptible. Their transcriptomic comparisons after the bacterial infection have the potential to identify expression candidate genes responsible for the resistance. Microarray analysis of gene expression changes in blue catfish liver after infection with the pathogen indicated a strong upregulation of several pathways involved in the inflammatory immune response and potentially in innate disease resistance. A multifaceted response to infection could be observed, encompassing the complement cascade, iron regulation, inflammatory cell signaling, and antigen processing and presentation. The induction of several components of the MHC class I-related pathway following infection with an intracellular bacterium is reported here for the first time in fish. A comparison with previously published expression profiles in the channel catfish liver was also made and the microarray results extended by use of quantitative RT-PCR. Our results add to the understanding of the teleost immune responses and provide a solid foundation for future functional characterization, genetic mapping, and QTL analysis of immunity-related genes from catfish.