Abstract: 【Aim】 Time interval measuring enzyme (TIME-EA4) is a diapause bioclock protein in insects. This study aims to clone TIME-EA4 cDNA and analyze its spatiotemporal expression patterns in various developmental stages and different tissues of Chilo suppressalis, including the populations collected in the fields, and diapause and non-diapause populations induced at various temperatures. 【Methods】 Full-length cDNA sequence of TIME-EA4 gene of C. suppressalis was cloned by using RACE technique. The relative expression levels of TIME-EA4 in different developmental stages, different tissues of the 6th instar larvae, larvae of field populations collected in different seasons and the 6th instar larvae from different populations of the moth treated for one hour at different temperatures were assayed by real-time PCR. 【Results】 The full-length cDNA of C. suppressalis TIME-EA4 is 821 bp, with an open readingframe of 516 bp encoding 172 aa. TIME-EA4 was ubiquitously expressed, but with higher expression levels in early pupae and adults, and in the head, fat body and midgut of the 6th instar larvae. And the expression level of TIME-EA4 in the tissues of diapause larvae was much higher than that in the non-diapause larvae. Interestingly, the expression level of TIME-EA4 was significantly increased 3-fold in diapause groups compared with that in the non-diapause individuals. The abundance of TIME-EA4 gene was elevated at ≤10℃ in the non-diapause population, and reached the peak at 10℃. However, TIME-EA4 expression was not significantly altered by temperature change in the diapause population. 【Conclusion】 These results suggest that the enhanced expression of TIME-EA4 correlates with the low temperature stress or low temperature-induced diapause in C. suppressalis. This study forms a basis for further investigation of TIME-EA4 in the diapause of agricultural pests.

Key words: Chilo suppressalis, diapause, temperature induction, bioclock protein, TIME-EA4