Genome-wide characterization of mapk gene family in black rockfish Sebastes schlegelii and their expression patterns against Edwardsiella piscicida infection

Mitogen-activated protein kinases (MAPKs) play pivotal roles in response to environmental stresses and bacterial infections. Compared with those in the higher vertebrates, studies of mapk gene family are still limited in teleost. Identification, characterization, classification, and expression profiling of totally 15 mapk genes in black rockfish ( Sebastes schlegelii ) were conducted. Phylogenetic relationships show that these mapk genes could be divided into extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38 sub-families. In addition, gene structures, syntenic analysis, and selective pressure analysis are performed to confirm their annotations. Results of selective pressure analysis indicate that mapk1 , mapk3 , mapk7 , mapk10 , mapk11 , and mapk12 underwent significantly-positive selections, while the others genes such as mapk4 , mapk6 , mapk15 , mapk8a , mapk8b , mapk9 , mapk13 , mapk14a , and mapk14b were under purifying selections. Moreover, results of qRT-PCR indicate that mapk genes in 8 healthy tissues displayed different expression patterns. The expression patterns of several mapk genes including mapk12 , mapk13 , mapk14a , mapk14b , and mapk15 were significantly changed in mucosal tissues after Edwardsiella piscicida infection. This study demonstrates that mapk genes in black rockfish play vital prevention roles against bacterial infection, which not only helps us understand the structure and function of mapk genes in black rockfish, but also provides a reference to understand the role of mapk genes in teleost immune responses.