Abstract
c-Jun N-terminal kinase (JNK) is an important member of the MAPK family (mitogen-activated protein kinases), which has various functions such as participating in insect anti-stress response. In order to clarify the expression characteristics of HaJNK and its role in defense against Bt insecticidal protein in cotton bollworm Helicoverpa armigera, we cloned two HaJNK gene coding sequences HaJNK 1 and HaJNK 2 by PCR amplification. Bioinformatics analysis showed that the open reading frames of HaJNK 1 and HaJNK 2 genes were 1 191 bp and 1 143 bp, encoding 397 and 381 amino acids, respectively. Phylogenetic tree analysis showed that HaJNK 1 of H. armigera had high homology with that of Mythimna separata and HaJNK 2 of H. armigera is clustered with that of Bombyx mori. Quantitative real-time PCR was used to analyze the expression levels of HaJNK 1 and HaJNK 2 in different developmental stages and tissues. It was found that the expression levels of HaJNK 1 and HaJNK 2 were the highest in the stage of egg, following by female adults. The highest expression of HaJNK 1 was observed in gonads followed by salivary glands, and the highest expression of HaJNK 2 was in head followed by gonads. For the fourth instar larvae, after cotton bollworm fed on Cry1Ac, the expression levels of HaJNK 1 and HaJNK 2 in midgut were significantly increased. It was speculated that the HaJNKs of H. armigera might be involved in emergency response and antistress response against Bt insecticidal protein.