摘要
重金属污染已经对生物产生强大的选择压力。为了探索麦长管蚜Sitobion avenae经重金属镉长期胁迫后超氧化物歧化酶(SOD)和乙酰胆碱酯酶(AchE)基因表达的变化规律,本研究模拟自然环境条件,用Cd2+溶液浇灌土壤,通过土壤-小麦-麦长管蚜体系连续处理麦长管蚜20代,通过PCR扩增得到SOD和AchE基因cDNA片段,并用Real-time PCR的方法对连续处理5,10,15和20代的蚜虫进行基因表达水平的研究。结果表明:麦长管蚜SOD和AchE基因的表达水平会受Cd的浓度和连续处理世代数的影响。与对照相比,在5代和10代时呈现上调模式,而在处理20代后,其表达则受到了抑制。40 mg/kg是关键的浓度,高于此浓度时,基因的表达会出现下调模式。由此可见,低剂量的毒性胁迫会促使超氧化物歧化酶和乙酰胆碱酯酶的表达量增加,而高剂量胁迫则会限制两种酶的防御作用。
As a selective stress, heavy metal plays an important role during biological evolution. This study aims to explore the expression profiles of superoxide dismutase （SOD） and acetylcholine （AchE） gene in Sitobion avenae under the long-term exposure of cadmium （Cd）. In the simulative natural environment, the soil for growing wheat was irrigated with CdCl2 solution. S. avenae was treated with Cd for 20 generations through the system of soil-wheat-aphids. The SOD and AchE genes in S. avenae were cloned with PCR technique. Real-time PCR was adopted to estimate the transcript levels of SOD and AchE genes in S. avenae at the 5th, 10th, 15th and 20th generations, respectively. The results showed that the expression levels of the two genes were affected by both concentration of Cd and the number of generations. Compared to control, the two genes were over-expressed in the contaminated aphids at the 10th generation, but their expression was inhibited in the 20th generation. At the concentration of Cd higher than 40 mg/kg, the gene expression levels declined, suggesting that 40 mg/kg is the crucial concentration. These results suggest that the expression of SOD and AchE is promoted by the toxicity of low-dose and short-term pollutions, and the detoxification of superoxide dismutase and hydrolysis of acetylcholine, however, is inhibited under the high-dose and long-term stress.
出处
《昆虫学报》
CAS
CSCD
北大核心
2013年第7期747-753,共7页
Acta Entomologica Sinica
基金
国家自然科学基金项目(39970112
30470268)
关键词
麦长管蚜
重金属
镉
超氧化物歧化酶
乙酰胆碱酯酶
表达水平
Sitobion avenae heavy metal cadmium （Cd） superoxide dismutase （SOD） acetylcholine （AchE） expression level
