Body colours are important and striking features for individual survival and reproductive success, in particular in vertebrates where mating behaviour and mate preference may be strongly influenced by non-normal phenotypes. Pigmentation disorders may be generated by disruption of one or many independent genes as well as by environmental factors. The first discovery of albino yellow catfish (Pelteobagrus fulvidraco Richardson) with golden skin colour from fish farms in China provides us valuable material to study the molecular mechanism underlying the abnormalities of pigmentation. In this study, transcriptome sequencing of fin tissues corresponding to the distinct body colours, wild type and mutant albino yellow catfish, were performed using Illumina sequencing technology. Based on next-generation sequencing technology and de novo assembly, we generated a transcriptome of P. fulvidraco. A number of genes differentially expressed between the wild types and albinos were identified, suggesting their contribution to the different phenotypes and fitness. However, non-synonymous mutations result from single nucleotide substitutions residing in coding regions may not contribute to such differences. Based on the high-throughput expression data generated for the two different types of P. fulvidraco, we found that alterations of expression pattern may be more common than non-synonymous mutations. The transcriptome of P. fulvidraco will be an invaluable resource for subsequent comparative genomics and evolutionary analyses of this economically important fish.
A teleost’s kidney was divided into head kidney and trunk kidney. The head kidney is an important lymphatic organ, while the trunk kidney mainly performs osmotic pressure regulation and excretion functions. Previous studies have shown that the teleost’s head kidney exerts a strong immune response against pathogen invasion, while the mechanism of immune response in the trunk kidney is still rarely reported. Therefore, in this study, we established an Infectious hematopoietic necrosis virus (IHNV) immersion infection model to compare the similarities and differences of immune response mechanisms between the head kidney and trunk kidney against viral infection. The results showed that IHNV infection causes severe tissue damage and inflammatory reaction in the head and trunk kidney, triggers a series of interferon cascade reactions, and produces strong immune response. In addition, the transcriptome data showed that the head kidney and trunk kidney had similar immune response mechanisms, which showed that the NOD-like receptor signaling pathway and Toll-like receptor signaling pathway were activated. In conclusion, despite functional differentiation, the teleost’s trunk kidney still has a strong immune response, especially the interferon-stimulated genes, which have stronger immune response in the trunk kidney than in the head kidney when responding to IHNV infection. This study contributes to a more comprehensive understanding of the teleost immune system and enriches the theory of kidney immunity in teleosts.