中文摘要：

为明确植物源活性物质姜黄素对朱砂叶螨Tetranychus cinnabarinus的杀螨作用机理,克隆并分析了6条朱砂叶螨几丁质酶基因（Tc CHTs）的c DNA序列,利用RT-q PCR技术,测定了不同发育阶段的螨体内几丁质酶基因表达的情况,同时研究了姜黄素作用下几丁质酶基因表达的变化。结果表明：6条几丁质酶基因（Tc CHIT1、Tc CHIT2、Tc CHIT3、Tc CHT4、Tc CHT5和Tc CHT6）有不同的结构域,预测其蛋白质分子质量分别为60.80、69.03、104.32、59.75、45.63和49.05 k Da,等电点分别为5.44、8.65、6.23、6.07、6.12和8.27。6条基因的表达量均为幼螨和若螨时期显著高于卵和成螨时期。不同浓度姜黄素处理朱砂叶螨若螨24 h后,6条基因的表达量均有不同程度下调,其中Tc CHIT1和Tc CHT5的下调更为显著。研究结果表明,姜黄素对朱砂叶螨的杀螨作用机制之一可能是通过抑制几丁质酶的活性,进而影响几丁质的降解过程,最终因螨体壁受损而导致螨不能正常生长发育。

英文摘要：

The mechanism of the curcumin（substance from plants） against Tetranychus cinnabarinus was elucidated. The six c DNA sequences of chitinases of Tetranychus cinnabarinus（Tc CHTs） were cloned and analyzed. Quantitative RT-q PCR was used to detect the expression levels of the chitinase genes across different developmental stages of T. cinnabarinus. Then the effect of curcumin on the gene expression of Tc CHTs was determined. The results indicated： The six CHTs c DNA sequences had different domains. These genes had predicted molecular weights of 60.80, 69.03, 104.32, 59.75, 45.63,and 49.05 k Da, respectively, and isoelectric points of 5.44, 8.65, 6.23, 6.07, 6.12 and 8.27, respectively.Quantitative RT-PCR results revealed that CHTs expression levels in larvaes and nymphs were higher than those in eggs and adults. After the nymph mites were exposed to curcumin for 24 h, the m RNA expression levels of Tc CHTs significantly decreased. It is noteworthy that Tc CHIT1 and Tc CHT5 were more sensitive than others. The results indicated that one of the acaricidal mechanisms of curcumin might be inhibiting the activity of chitinase. By affecting the degradation of chitin, the epidermal degeneration was inhibited, which will lead to the damage of normal growth and development of the mites integument.