【作者】 卢芙萍；

【导师】 马恩波； 段毅豪；

【作者基本信息】 山西大学 ， 动物学， 2004， 硕士

【摘要】 近年来随着耕作制度、生态环境的改变，以及全球异常气候条件的影响，中华稻蝗发生也变得更加严重。由于生态和地理环境的不同，生活于不同地区的中华稻蝗种群具有不同程度的差异。所以对中华稻蝗的防治研究应以种群为单位，通过了解不同种群的遗传结构，为防治研究提供基础资料。研究表明，马拉硫磷的急性致死作用与中华稻蝗等位酶基因型之间存在相关关系，所以等位酶基因型可能作为中华稻蝗潜在的抗药性监测指标。中华稻蝗是一种地域性的蝗虫种类，对水的依赖性比较强，中等程度的地理隔离将会显著限制种群间的基因交流，从而导致种群内遗传多样性的产生和不同地域种群间遗传分化的存在。不同种群间遗传结构的分化就使得农药的抗药性监测不能一概而论，而是要因地制宜，因种群遗传背景而异。 本文通过等位酶分析方法研究了山西和陕西中华稻蝗三个自然种群的遗传结构和种群间的分化程度。毒力实验测得马拉硫磷对各个种群的LC₅₀值，并用相应LC₅₀浓度的马拉硫磷分别处理这几个中华稻蝗种群，处理个体数为276到533头。选取其中五个多态性强且染色稳定的酶基因座作为分子遗传标记，应用等位酶分析检测马拉硫磷急性毒性处理后中华稻蝗存活个体与死亡个体的基因型，以研究各中华稻蝗种群等位酶基因型与马拉硫磷致死作用之间可能的相关关系。若这种相关关系确实存在，则可通过比较不同基因型中华稻蝗个体死亡率之间的差异，确定敏感和抗性基因型标记，探讨等位酶遗传标记物在中华稻蝗不同地域种群间的变化特征，进而确定种群的抗性水平。 对十三个基因座（Adk、Ck、α-Gpdh、Hex-1、Hex-2、Idh-1、Idh-2、Ldh、Me、Mdh-1、Mdh-2、Pgi和Pgm）的等位酶分析结果表明，三个中华稻蝗种群在种群内和种群间都存在遗传多样性差异。仅Ck、Idh-1和Mdh-2在三个种群中为单态基因座，其余10个基因座至少在一个种群中具有多态性（95％标准）。在Ldh基因座，等位基因表现出一种渐变的趋势，等位基因α的频率在晋北的代县阳明堡种群为0.631，晋中的太原晋源种群是0.720，而在陕西长安县杨桥镇种群为0.852。多态基因座百分率（P）相对较高（53.8％～61.5％）；平均每个基因座的等位基因数目（A），山西代县阳明堡种群为2.1，山西太原晋源种群为2.4，陕西长安县杨桥镇种群为2.7；平均杂合度的观测值（Ho）阳明堡种群为0.176，晋源种群为0.177，杨桥镇种群0.181。除Ldh和Pgi在三个中华稻蝗种群均符合Hardy-Weinberg平衡外，其余绝大多数基因座的基因型频率显著偏离Hardy-Weinberg平衡，Me和Pgm两个基因座的基因型频率在三个种群中都极显著偏离Hardy-Weinberg平衡预期值。尽管十三个基因座中有九个基因座的F_s（?）值都显著或极显著偏离Hardy-Weinberg平衡，但平均的F_s（?）并不偏离Hardy-Weinberg平衡(F_s（?）=0.037，P＞0.05)。Nei’s遗传相似性系数较高（0.990～0.996），说明，尽管三个种群之间存在明显的地理隔离，但是它们之间的遗传分化却比较小。在以Roger’s遗传距离为基础的聚类分析中，距离较近的山西代县阳明堡种群和太原晋源种群先相聚，然后再与陕西长安县的杨桥镇种群相聚，表明三个中华稻蝗种群的遗传距离与地理位置和地理距离之间存在较为明显的止相关关系。然而，还需检测人量的种群以支持目前结果。 基因型一毒性的相关关系分析结果表明，在具有选择性的等位酶基因座，中华稻蝗基因型与马拉硫磷的致死作用显著相关。二个中华稻蝗种群之间存在一定的遗传分化，虽然这种分化并未达到统计学上的显著差异（只1=0.037士0.020，尸>0.05），但是这种差异已经使得不同种群对马拉硫磷急性毒性的反应表现不同。陕西长安县杨桥镇种群的尸乡n一bb和尸罗刀一cc基因型个体死亡率差异显著，甩，:一bb基因型中华稻蝗个体对马拉硫磷毒性存在较大的耐受性（死亡率为49%），而助。一cc基因型中华稻蝗个体却对马拉硫磷毒性表现非常敏感（死亡率为68%）。另外，在该种群，等位基因助。一b与尸g子1，一a、尸罗，了一及尸脚一d之间均存在显著差异，D..有高频率的等位基因PLvln一b的中华稻蝗个体对马拉硫磷毒性存在较大的耐受性;山两代县件!明堡种群的棺i一动和Pgi一bb基因型个体的死亡率差异显著，Pgi一ab基因型中华稻蝗个体对马拉硫磷毒性存在较大的耐受性（52%），而Pgi一bb基因型中华稻蝗个体却对马拉硫磷毒性表现非常敏感（64%）;山西太原晋源镇中华稻蝗个体的Pgl’-c。和尸脚一a。都与马拉硫磷致死性显著相关，具有甩i一c’c和助n一ac基因型的个体全部存活了卜来，而其他Pgi基因型个体的死亡率最低为48%，勺。其他基因型个体的死亡率至少为46%，另外在该种群，人介一d的死亡率最高，与人了召一a、娥一b和人介一c的死亡率之间均存在显著的差异。Roger’s遗传距离表明马拉硫磷急性毒性对各中华稻蝗种群的遗传结构均存在分化。更多还原

【Abstract】 The massive outbreaks of Oxya chinensis had become increasingly serious in recently years along with the changes of the agricultural practices, ecological environments and the global climatic conditions. It is commonly believed that insect populations have different characters as a result of adaptation to each geographic ecological and environment, implying that the population control may vary depending on the target population genetic structure. Such knowledge can provide useful information for the insect swarming prevention and overall pest management. Previous studies have related differential malathion acute lethal effects on allozyme genotypes of Oxya chinensis, suggesting that the allozyme genotypes may be a potential indicator to evaluate resistance of Oxya chinensis to malathion toxicity. The terrestrial grasshopper of Oxya chinensis heavily depends on water in its habitats. A moderate geographical barrier might significantly restrict the gene exchange among populations, which may result in the accumulation of local genetic diversity within population and the development of genetic divergence among various populations. The existence of the population genetic differentiation implies that the monitoring of resistance to pesticides are needed thorough such differences and the control practices are dependent on local conditions with the consideration of population’s genetic background.This thesis studied the genetic structure of three populations of Oxya chinensis from Shanxi and Shaanxi province and estimated the level of genetic divergence. The LC50 values of the samples from each population were then measured. 276 to 533 individuals of Oxya chinensis in each population were injected with malathion at a concentration of corresponding LC50 values. The survivor and the dead individuals were then assayed using allozyme analysis to individually examine the genotypes. Five polymorphic loci were selected as molecule genetic marker to explore the possible correlation between allozyme genotypes and malathion lethal effects. When the significant allozyme effects on the moralities were observed, the pairs of individuals of each genotype were either defined as the resistance or sensitive genotypes according to the mortality difference. Therefore, the genotype may be useful as a marker to survey the population resistance level.The allozyme analysis of thirteen loci (Adk, Ck, -Gpdh, Hex-1, Hex-2, Idh-1, Idh-2, Ldh, Me, Mdh-1, Mdh-2, Pgi and Pgm) demonstrated that the genetic variation within a population and among all the three populations. Loci of Ck, Idh-1 and Mdh-2 were found monmorphic in all three populations whereas more than one alleles were observed at the rest loci. A clinal tendency in allele frequency was observed at the locus of Ldh. From north to south the frequency of Ldh-a was 0.631 in YM population (Yangmingbu, Dai county, Shanxi), 0.720 in JY population (Jinyuan district, Taiyuan, Shanxi), and 0.852 in YQ population (Yangqiao, Chang’an County, Shaanxi) The three Oxya chinensis populations showed relatively high percentage of polymorphic loci (53.8% to 61.5%), the mean number of alleles per locus (A=2.1~2.7) and observed heterozygosity (Ho=0.176-0.181). The genotype frequency at most loci significantly deviated from Hardy-Weinberg expectations except for Ldh and Pgi in all the three populations. Me and Pgmwere significantly deviated from Hardy-Weinberg equilibrium in all the three populations. Although Fst in nine loci were significantly deviated from Hardy-Weinberg equilibrium, the overall Fst was not deviated from Hardy-Weinberg equilibrium (overall Fst=0.037, P>0.05). Nei’s genetic identity were high (0.990 to 0.996) and showing the less divergence level among the three populations inspite of the obvious geographic isolations. In cluster analysis based on Roger’s genetic distance, the geographically closer populations of YM and JY grouped first and then grouped with YQ population. This may imply that the genetic distance was positively correlated with geographic distance. However more pop更多还原