Monochamus alternatus Hope (Coleoptera: Cerambycidae) warrants attention as a dominant transmission vector of the pinewood nematode, and it exhibits tolerance to high temperature. Heat shock protein 70 (HSP70) family members, including inducible HSP70 and heat shock cognate protein 70 (HSC70), are major contributors to the molecular chaperone networks of insects under heat stress. In this regard, we specifically cloned and characterized three MaltHSP70s and three MaltHSC70s. Bioinformatics analysis on the deduced amino acid sequences showed these genes, having close genetic relationships with HSP70s of Coleopteran species, collectively shared conserved signature structures and ATPase domains. Subcellular localization prediction revealed the HSP70s of M. alternatus were located not only in the cytoplasm and endoplasmic reticulum but also in the nucleus and mitochondria. The transcript levels of MaltHSP70s and MaltHSC70s in each state were significantly upregulated by exposure to 35–50°C for early 3 h, while MaltHSP70s reached a peak after exposure to 45°C for 2–3 h in contrast to less-upregulated MaltHSC70s. In terms of MaltHSP70s, the expression threshold in females was lower than that in males. Also, both fat bodies and Malpighian tubules were the tissues most sensitive to heat stress in M. alternatus larvae. Lastly, the ATPase activity of recombinant MaltHSP70-2 in vitro remained stable at 25–40°C, and this recombinant availably enhanced the thermotolerance of Escherichia coli. Overall, our findings unraveled HSP70s might be the intrinsic mediators of the strong heat tolerance of M. alternatus due to their stabilized structure and bioactivity.

中文翻译：

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松叶甲虫、Monochamus alternatus Hope（鞘翅目：天牛科）中热休克蛋白 70 的表征、表达谱和耐热性分析

独角仙Hope（鞘翅目：Cerambycidae）作为松材线虫的主要传播媒介值得关注，它表现出对高温的耐受性。热休克蛋白 70 (HSP70) 家族成员，包括诱导型 HSP70 和热休克同源蛋白 70 (HSC70)，是热应激下昆虫分子伴侣网络的主要贡献者。在这方面，我们专门克隆并表征了三个 MaltHSP70 和三个 MaltHSC70。对推导的氨基酸序列的生物信息学分析表明，这些基因与鞘翅目物种的 HSP70 具有密切的遗传关系，共同共享保守的特征结构和 ATP 酶结构域。亚细胞定位预测揭示了 HSP70M.alternatus不仅存在于细胞质和内质网中，还存在于细胞核和线粒体中。每个州的 MaltHSP70s 和 MaltHSC70s 的转录水平在暴露于 35-50°C 3 小时后显着上调，而 MaltHSP70s 在暴露于 45°C 2-3 小时后达到峰值，而 MaltHSC70s 上调较少。MaltHSP70s在女性中的表达阈值低于男性。此外，脂肪体和马尔皮基小管都是对热应激最敏感的组织。M.alternatus幼虫。最后，重组 MaltHSP70-2 的 ATPase 活性体外在 25-40°C 下保持稳定，这种重组有效地增强了耐热性大肠杆菌。总体而言，我们的研究结果揭示了 HSP70 可能是其强耐热性的内在介质。M.alternatus由于它们稳定的结构和生物活性。