Molecular cloning, characterization, and mRNA expression of two Cryptochrome genes in Helicoverpa armigera (Lepidoptera: Noctuidae).

Light is a major environmental signal for insect circadian. In this study, we isolated two cryptochrome (cry) genes from Helicoverpa armigera (Hübner) by reverse transcription polymerase chain reaction and RACE-PCR strategies, designated as Ha-cryl (GenBank accession GQ896502) and Ha-cry2 (GenBank accession GQ896503). Ha-CRY1 encoded a fly-like protein of 548 amino acids, while Ha-CRY2 encoded a mammal-like protein of 657 amino acids. Both of these proteins had two conserved domains: a DNA photolyase domain and a flavin adenine dinucleotide (FAD) binding seven domain, and alignment of the amino acid sequence indicated that there was a high degree of homology between the CRYs of H. armigera and other insects. Real-time polymerase chain reaction revealed that: 1) Ha-cry1 and Ha-cry2 mRNA expressions were neither organ-specific nor developmental-stage-specific. 2) Under the light-dark cycle (16:8 L:D), Ha-cry1 abundance tended to increase during the day, then decrease in the night, whereas the expression pattern of Ha-cry2 was opposite. 3) The cyclings of Ha-cry1 and Ha-cry2 expression were disturbed by constant light and darkness. Our study has significant importance for the further study of the functions of the Ha-cry genes and potential control of the cotton bollworm.