The cotton bollworm Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), an important pest of cotton, is detrimental to cotton production. Light from UV-A ultraviolet lamps is regarded as a form of environmental stress for insects. In order to investigate the response of H. armigera exposed to UV-A, we explored Hap38 MAPK expression and functions. We hope that the findings of this study will lay the foundation for future investigations into the insect’s phototaxis mechanism. A p38 MAPK was cloned and named Hap38 MAPK. A phylogenetic tree showed that Hap38 MAPK was highly conserved. The gene was highly expressed in the thorax and females. Under UV-A stress, the expression of the gene decreased significantly. After silencing Hap38 MAPK, the activity of the antioxidant enzymes SOD, POD, CAT, and GR decreased. This study suggested that Hap38 MAPK responds to UV-A irradiation and plays critical roles in the defense response to environmental stresses.

Background: As an environmental stress factor, ultraviolet-B (UV-B) radiation directly affects the growth and development of Myzus persicae. Excessive UV-B stress leads to DNA, membrane lipid, and protein damage by the production of reactive oxygen species. However, M. persicae can adaptively respond to such environmental stress by activating the relevant mechanisms in the body. How M. persicae responds to UV-B stress and the molecular mechanisms underlying this adaptation remain unknown. Results: Here, we compared and analyzed transcriptome data for M. persicae following exposure to a light-emitting diode fluorescent lamp and UV-B radiation for 30 min. We identified 758 significant differentially expressed genes (DEGs) following exposure to UV-B stress, including 423 upregulated and 335 downregulated genes. In addition, enrichment analysis using the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes databases illustrated that these DEGs are associated with antioxidation and detoxification, metabolic and protein turnover, immune response, and stress signal transduction. Simultaneously, these DEGs are closely related to the adaptability to UV-B stress.Conclusions: Our results suggest that UV-B stress is associated with a wide range of physiological effects in M. persicae. Our research can raise awareness of the mechanisms of insect responses to UV-B stress.