Up-regulation of cryptochrome 1 gene expression in cotton bollworm (Helicoverpa armigera) during migration over the Bohai Sea

Liyu Yang; Yingjie Liu; Philip Donkersley; Pengjun Xu

doi:10.7717/peerj.8071

Up-regulation of cryptochrome 1 gene expression in cotton bollworm (Helicoverpa armigera) during migration over the Bohai Sea

PeerJ. 2019 Nov 15:7:e8071. doi: 10.7717/peerj.8071. eCollection 2019.

Authors

Liyu Yang^#¹, Yingjie Liu^#¹, Philip Donkersley², Pengjun Xu¹

Affiliations

¹ Chinese Academy of Agricultural Sciences, Tobacco Research Institute, Qingdao, Shandong, China.
² Lancaster Environment Centre, Lancaster University, Lancaster, UK.

^# Contributed equally.

Abstract

Cryptochromes (CRYs) are flavoproteins and play a pivotal role in circadian clocks which mediate behavior of organisms such as feeding, mating and migrating navigation. Herein, we identified novel transcripts in Helicoverpa armigera of six isoforms of cry1 and seven isoforms of cry2 by Sanger sequencing. Phylogenetic analysis showed that the transcripts of cry1 and cry2 align closely with other insect crys, indicating within-species divergence of Hacry. A dn/ds analysis revealed that the encoding sequence of the cry1 was under purifying selection by a strong negative selection pressure whereas the cry2 was less constraint and showed a less strong purification selection than cry1. In general, Hacrys were more abundantly transcribed in wild migrating populations than that in laboratory maintained populations, and expression of the cry2 was lower than cry1 in all samples tested. Moreover, when compared with the migrating parental population, offspring reared in laboratory conditions showed a significant reduction on transcription of the cry1 but not cry2. These results strongly suggest that cry1 was more related to the migration behavior of H. armigera than cry2.

Keywords: Cryptochromes; Expression analysis; Helicoverpa armigera; Migration; Transcripts.

Grants and funding

This work was supported by the Agricultural Science and Technology Innovation Program (ASTIP-TRIC04), the Key S&T project of China National Tobacco Corporation (110201601022(LS-02)), and the Science Foundation for Young Scholars of Institute of Tobacco Research of CAAS (2015B03). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.