AUTHOR=Jiang Yan-Dong , Yuan Xin , Zhou Wen-Wu , Bai Yue-Liang , Wang Gui-Yao , Zhu Zeng-Rong 

TITLE=Cryptochrome Regulates Circadian Locomotor Rhythms in the Small Brown Planthopper Laodelphax striatellus (Fallén)

JOURNAL=Frontiers in Physiology

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2018.00149

DOI=10.3389/fphys.2018.00149

ISSN=1664-042X

ABSTRACT=<p>Most living organisms have developed internal circadian clocks to anticipate the daily environmental changes. The circadian clocks are composed of several transcriptional-translational feedback loops, in which cryptochromes (CRYs) serve as critical elements. In insects, some CRYs act as photopigments to control circadian photoentrainment, while the others act as transcriptional regulators. We cloned and characterized two <italic>cryptochrome</italic> genes, the <italic>Drosophila</italic>-like (<italic>lscry1</italic>) and vertebrate-like (<italic>lscry2</italic>) genes, in a rice pest <italic>Laodelphax striatellus</italic>. Quantitative real-time PCR showed that <italic>lscry1</italic> and <italic>lscry2</italic> expressed ubiquitously from nymph to adult stages as well as in different tissues. The transcript levels of <italic>lscry2</italic> fluctuated in a circadian manner. Constant light led to arrhythmic locomotor activities in <italic>L. striatellus</italic>. It also inhibited the mRNA oscillation of <italic>lscry2</italic> and promoted the transcription of <italic>lscry1</italic>. Knockdown of <italic>lscry1</italic> or <italic>lscry2</italic> by RNA interference (RNAi) reduced the rhythmicity of <italic>L. striatellus</italic> in constant darkness, but not in light dark cycles. These results suggested that <italic>lscry1</italic> and <italic>lscry2</italic> were putative circadian clock genes of <italic>L. striatellus</italic>, involved in the regulation of locomotor rhythms.</p>