Two strategies to unravel gene expression responses of host-microbe interactions in cod (Gadus morhua) larvae

• Main Authors: Torunn Forberg, Augustine Arukwe, Olav Vadstein
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: atlantic cod; Gadus morhua
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1061.1909; http://www.promicrobe.ugent.be/Public/Publications/Papers/Forberg_et_al_2011_Two_strategies.pdf

Abstract The commensal bacteria in the intestine play essential roles in the development and functionality of the host. To unravel the host^microbe interactions in Atlantic cod (Gadus morhua L.) larvae, we used two molecular approaches: (1) suppression subtractive hybridizationpolymerase chain reaction (SSH-PCR) to identify host gene responses and (2) expression analysis of selected genes reported to be di¡erentially expressed in gnotobiotic zebra¢sh in a previous study to determine whether these host responses are also conserved in cod. Suppression subtractive hybridization-PCR identi¢ed 156 transcripts putatively regulated by the presence of bacteria. However, out of 22 selected transcripts, only four were signi¢cantly di¡erentially expressed when quanti¢ed using quantitative (real-time) PCR. Expression analysis of selected genes from zebra¢sh revealed possible conservation of host responses for three out of eight genes analysed. For most of the genes quanti¢ed, the gene expression pattern varied between two biological replicates. This may re£ect differences in the bacterial composition in the rearing bottles, and denaturing gradient gel electrophoresis analysis con¢rmed signi¢cant di¡erences between the two replicates with regard to bacterial diversity. The varying e¡ects on gene expression caused by di¡er-ences in the microbial composition show the necessity of further studies where axenic cod larvae are compared with larvae raised in de¢ned and controlled (gnotobiotic) environments.