Abstract: [Objective] We cloned and characterized the cold shock domain-containing protein (CSP) gene in Chinese white pine beetle, Dendroctonus armandi in order to reveal the molecular mechanism in adaptability and cold-tolerance of D. armandi.[Method] The DarmCSP cDNA fragment of D. armandi was cloned. The phylogynetic tree was constructed with MEGA. The expression profiles of DarmCSP in D. armandi exposed to different low temperatures for different time series were detected by using real-time quantitative PCR.[Result]The cloned gene was named as DarmCSP. The result showed that the sequence from DarmCSP gene shared the highest level of amino acid sequence identity with CSP of the bark beetle species (Dendroctonus ponderosae) (92%). Real-time PCR analysis was used to detect the transcript levels of DarmCSP in D. armandi. The DarmCSP expression was up-regulated during the overwintering stage. The DarmCSP expression level of overwintering larvae (Jan. 2015) was 4.26 higher more than that early winter stage (Sep. 2014) and 2.90 higher than late winter stage (Mar. 2015). The DarmCSP expressions of overwintering larvae (Jan. 2015) and oversummering adults (Jul. 2015) were both up-regulated when beetles were exposed at different low temperatures for different duration. DarmCSP expression level of D. armandi increased with the exposure time increasing from 1 h to 24 h at -10℃, reaching its highest expression level at the time of 24 h. The DarmCSP reached the highest expression levels all for 12 h when larvae were exposed among -2, -4, -6 and -8℃. The DarmCSP can be induced from 0℃ to -10℃. The DarmCSP expression of oversummering adults was also up-regulated when beetles were exposed from 4℃ to -6℃. However, the expression level was lower than that of overwintering larvae.[Conclusion] The result of this study demonstrated that the DarmCSP expression in D. armandi can be induced by low temperature. The molecular changes participate in the adaptation process of D. armandi to low temperature. Our result can contribute more to further study on CSP and its physiological biochemical mechanism of Chinese white pine beetle.

Key words: Dendroctonus armandi, cold shock domain-containing protein, low temperature, gene expression, RT-qPCR