Gu Xinyue, Zhao Yan, Su Yun, Wu Jiajiao, Wang Ziya, Hu Juntao, Liu Lijun, Zhao Zihua, Hoffmann Ary A, Chen Bing, Li Zhihong
Department of Entomology, College of Plant Protection China Agricultural University Beijing China.
Guangdong Inspection and Quarantine Technology Center Guangzhou China.
Evol Appl. 2019 Apr 10;12(6):1147-1163. doi: 10.1111/eva.12793. eCollection 2019 Jun.
Many insects have the capacity to increase their resistance to high temperatures by undergoing heat hardening at nonlethal temperatures. Although this response is well established, its molecular underpinnings have only been investigated in a few species where it seems to relate at least partly to the expression of heat shock protein () genes. Here, we studied the mechanism of hardening and associated transcription responses in larvae of two invasive fruit fly species in China, and . Both species showed hardening which increased resistance to 45°C, although the more widespread hardened better at higher temperatures compared to which hardened better at lower temperatures. Transcriptional analyses highlighted expression changes in a number of genes representing different biochemical pathways, but these changes and pathways were inconsistent between the two species. Overall showed expression changes in more genes than . genes tended to be upregulated at a hardening temperature of 38°C in both species, while at 35°C many genes tended to be upregulated in but not . One candidate gene (the small heat shock protein gene, ) with a particularly high level of upregulation was investigated functionally using RNA interference (RNAi). We found that RNAi may be more efficient in , in which suppression of the expression of this gene removed the hardening response, whereas in RNAi did not decrease the hardening response. The different patterns of gene expression in these two species at the two hardening temperatures highlight the diverse mechanisms underlying hardening even in closely related species. These results may provide target genes for future control efforts against such pest species.
许多昆虫能够通过在非致死温度下进行热硬化来增强其对高温的耐受性。尽管这种反应已得到充分证实，但其分子基础仅在少数物种中进行过研究，在这些物种中，它似乎至少部分与热休克蛋白（）基因的表达有关。在此，我们研究了中国两种入侵果蝇物种幼虫的硬化机制及相关转录反应。两种物种均表现出硬化现象，对45°C的耐受性增强，尽管分布更广的物种在较高温度下硬化效果更好，而另一种在较低温度下硬化效果更好。转录分析突出了代表不同生化途径的一些基因的表达变化，但这些变化和途径在两个物种之间并不一致。总体而言，物种A比物种B表现出更多基因的表达变化。在两种物种中，许多基因在38°C的硬化温度下往往会上调，而在35°C时，许多基因在物种A中往往会上调，而在物种B中则不然。我们使用RNA干扰（RNAi）对一个上调水平特别高的候选基因（小热休克蛋白基因）进行了功能研究。我们发现RNAi在物种A中可能更有效，在该物种中抑制该基因的表达消除了硬化反应，而在物种B中RNAi并未降低硬化反应。这两种物种在两种硬化温度下不同的基因表达模式突出了即使在亲缘关系密切的物种中硬化背后的多种机制。这些结果可能为未来针对此类害虫物种的防治工作提供靶标基因。
