title: Molecular Cloning and Induced Expression of Six Small Heat Shock Proteins Mediating Cold-Hardiness inHarmonia axyridis(Coleoptera: Coccinellidae).
abstract: The main function of small heat shock proteins (sHSPs) as molecular chaperones is to protect proteins from denaturation under adverse conditions. Molecular and physiological data were used to examine the sHSPs underlying cold-hardiness inHarmonia axyridis. Complementary DNA sequences were obtained for sixH. axyridissHSPs based on its transcriptome, and the expression of the genes coding for these sHSPs was evaluated by quantitative real-time PCR (qRT-PCR) in several developmental stages, under short-term cooling or heating conditions, and in black and yellow females of experimental and overwintering populations under low-temperature storage. In addition, we measured water content and the super cooling and freezing points (SCP and FP, respectively) ofH. axyridisindividuals from experimental and overwintering populations. The average water content was not significantly different between adults of both populations, but the SCP and FP of the overwintering population were significantly lower than that of the experimental population. Overall, the six sHSPs genes showed different expression patterns among developmental stages. In the short-term cooling treatment,Hsp16.25andHsp21.00expressions first increased and then decreased, whileHsp10.87andHsp21.56expressions increased during the entire process. Under short-term heating, the expressions ofHsp21.00, Hsp21.62, Hsp10.87, andHsp16.25showed an increasing trend, whereasHsp36.77 firstdecreased and then increased. Under low-temperature storage conditions, the expression ofHsp36.77decreased, while the expressions ofHsp21.00andHsp21.62were higher than that of the control group in the experimental population. The expression ofHsp36.77 firstincreased and then decreased, whereasHsp21.56expression was always higher than that of the control group in the overwintering population. Thus, differences in sHSPs gene expression were correlated with theH. axyridisforms, suggesting that the mechanism of cold resistance might differ among them. Although,Hsp36.77, Hsp16.25, Hsp21.00, andHsp21.62regulated cold- hardiness, the only significant differences between overwintering and experimental populations were found forHsp16.25andHsp21.00.
authors.affiliation: College of Life and Environmental Sciences, Hangzhou Normal University Hangzhou, China.
authors.forename: Hui-Juan
authors.initials: HJ
authors.lastname: Wang
authors.affiliation: College of Life and Environmental Sciences, Hangzhou Normal University Hangzhou, China.
authors.forename: Zuo-Kun
authors.initials: ZK
authors.lastname: Shi
authors.affiliation: College of Life and Environmental Sciences, Hangzhou Normal University Hangzhou, China.
authors.forename: Qi-Da
authors.initials: QD
authors.lastname: Shen
authors.affiliation: College of Life and Environmental Sciences, Hangzhou Normal University Hangzhou, China.
authors.forename: Cai-Di
authors.initials: CD
authors.lastname: Xu
authors.affiliation: Institute of Plant and Environment Protection, Beijing Academy of Agriculture and Forestry Sciences Beijing, China.
authors.forename: Bing
authors.initials: B
authors.lastname: Wang
authors.affiliation: College of Forestry, Northeast Forestry University Harbin, China.
authors.forename: Zhao-Jun
authors.initials: ZJ
authors.lastname: Meng
authors.affiliation: College of Life and Environmental Sciences, Hangzhou Normal University Hangzhou, China.
authors.forename: Shi-Gui
authors.initials: SG
authors.lastname: Wang
authors.affiliation: College of Life and Environmental Sciences, Hangzhou Normal University Hangzhou, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Tang
authors.affiliation: Institute of Plant and Environment Protection, Beijing Academy of Agriculture and Forestry Sciences Beijing, China.
authors.forename: Su
authors.initials: S
authors.lastname: Wang
keywords: Harmonia axyridis; cold-hardiness; freezing point; gene expression; qRT-PCR; small heat shock protein; super cooling point