【作者】 都二霞；

【导师】 赵惠燕；

【作者基本信息】 西北农林科技大学 ， 农业昆虫与害虫防治， 2006， 硕士

【摘要】 桃蚜(Myzus persicae)属同翅目,蚜科,瘤蚜属,是世界上分布最广、危害最大的蚜虫类害虫之一。其生长季节行孤雌生殖,繁殖快且量大,种下分化迅速。影响蚜虫种群遗传多样性因素很多,主要包括寄主选择和环境胁迫。高强度紫外胁迫对昆虫产生了强烈的选择压力,从而导致了昆虫的遗传分化和基因流动。本文观察了紫外诱变对蚜虫生态遗传学的影响,同时采用生命表等生态学和分子生态学方法,如遗传标记(微卫星和线粒体COⅠ-Ⅱ部分序列分析)和遗传多样性指标(基因多样性和位点多态率),从生态学和分子生态学不同水平测定了不同照射时间(2 h、4 h、6 h)和照射强度(15 W、30 W、45 W)下紫外线诱导桃蚜基因的遗传变异,并根据遗传距离进行聚类分析,主要结果如下:1.不同紫外线照射时间和照射强度处理对桃蚜F2代的生态学参数均有不同程度的影响,表明紫外线照射处理的当代蚜虫的生态学影响已经遗传给后代。在2 h处理水平下,15 W强度辐射处理桃蚜种群的内禀增长率最高,达0.265;而后,随着辐射强度的增加,内禀增长率值急剧下降;而在6 h照射时间处理水平下,随着辐射强度的升高,内禀增长率呈现平稳甚至上升趋势;此结果也表明在低剂量辐射下,蚜虫表现出适当的刺激反应,而在高剂量辐射下,蚜虫对辐射的耐受力增加。2.从扩增的桃蚜基因组大小证实蚜虫基因组大小为21kb左右。且在多次实验摸索的基础上,优化了桃蚜微卫星扩增和mtDNA COⅠ-Ⅱ部分序列特异扩增的反应体系。3.微卫星引物33.15核心序列、(CAC)5、(GATA)4对诱变桃蚜F2代的扩增图谱呈现出丰富的多态性,其扩增片断大小分别在221-2125 bp、264-1694 bp、407-1923 bp之间。此结果从分子水平证明处理F2代桃蚜的DNA发生了变异,揭示出紫外诱导可遗传的变异,且变异大小是由辐射时间和辐射强度共同决定。4.遗传多样性指标的方差分析结果表明,对于平均多态位点率,2 h处理是平均多态位点率的临界值,超过2 h, F2代平均多态位点率发生显著变异;对于平均基因多样度,对照与不同时间处理间差异显著;研究结果也表明低剂量紫外照射可增加蚜虫的免疫性,高剂量辐射则导致桃蚜的基因发生变异。更多还原

【Abstract】 Peach aphid (Homoptera: Aphididae), Myzus persicae (Sulzer), is one of the most economically important pests that result in decreasing of yield and quality of crops of agricultural and horticultural crops throughout the world. What’s worse, its reproduction is fast and the number of generations is large. Its interspecies differenciation is also considerable and fast, which associates with host plants, environmental factors.Continuing depletion of stratospheric ozone and subsequent increases in deleterious ultraviolet radiation at the Earth’s surface has huge exerted pressure on organism, which lead to the genetic mutation and heredity drifting. So far the molecular mechanisms of biological action of UV radiation on insect have not been completely clarified yet. Therefore, in this study, we observed the biology on the aphids under UV, at the same time, two genetic markers (the PCR technique with microsatellite primers and Gene Sequence Analysis on Partial Mitochondria COⅠ-Ⅱ)and genetic diversity indexes (the rate of loci polymorphism and gene diversity )were used to detect the mutation of the F2 generation after UV-irradiation. At last, according the genetic distance, the clustering analysis were selected as follows:1. Based on the life-fecundity table of irradiation population in lab, the ecological parameters changed with the time and intensity that showed that the ecological mutation is delivered to the progeny. After UV-induced 2 h, the intrinsic rate reached the top, its value is 0.265. Then it dropped greatly. After UV-induced 6 h, the intrinsic rates indicated the increasing tendency at the density considered.the result suggested that the aphid produced excitement effect at the lower dose. At the mean time higher dose increased its endure tolerance.2. Extracting DNA from small sized insect proved that the size of the green peach aphid’s genome DNA is about 21 kb. On the basis of many times of experiments, A optimized reaction system about the microsatellite PCR amplification and partial COⅠ-Ⅱgene amplification of the green peach aphid was proposed.3. It is clear that the result of polymorphic bands shows the abundance among the aphids after different UV radiation with three primers.更多还原