【作者】 关秀杰；

【导师】 张志涛；

【作者基本信息】 中国农业科学院 ， 农业昆虫与害虫防治， 2004， 硕士

【摘要】 本文从稻褐飞虱不同致害性种群的DNA多态性入手，寻找种群的特异性标记，以特异性标记为基础，对种群进行纯化，并进行了相对纯合种群的生物学比较实验和遗传学实验，对稻褐飞虱致害性转变进行了初步探讨，主要结果如下： 一、不同致害性种群，群体内和群体间的遗传多样性分析表明，无论雌雄虫，TN1种群的遗传多样性大于Mudgo与ASD7种群，不同致害性种群群体间的基因多样度大于群体内的基因多样度。具有多态性的条带聚类分析表明，雌雄虫联合聚类，同一致害性种群的不同个体可以归为一组，雌雄两性试虫分为不同两组，揭示不同致害性种群间存在明显遗传差异，致害性的遗传可能与性染色体连锁。 二、部分具有种群特异性的RAPD片段，回收、克隆、测序，转化为SCAR标记，只有TN1种群的一个特异片段转化成功，大小约为410bp左右，出现频率为60％左右。每个种群近100多个个体的验证，只有TN1种群出现此特异标记，Mudgo与ASD7种群没有，这条标记是TN1种群的特有标记。序列同源性比较分析，与Genbank中的序列没有较高的同源性。 三、以TN1种群的特异片段为标记，筛选获得了两个群体，即具有特异标记的群体(“+／+”)与不具有特异标记的群体(“-／-”)。若虫在感虫品种TN1上饲养，成虫在感虫品种TN1上测定，两种群的平均体重增量、平均蜜露分泌量不存在显著差异，但成虫在抗虫品种Mudgo上测定，“+／+”种群的平均体重增量、平均蜜露分泌量、平均寿命都显著高于“-／-”种群。若虫在抗虫品种Mudgo上饲养，成虫在抗虫品种Mudgo上测定，F1代两种群的平均体重增量、平均蜜露分泌量不存在显著差异，“-／-”组合数值略大于“+/+”组合数值：F2代“-／-”组合在Mudgo上的平均体重增量、平均蜜露分泌量显著大于“+/+”组合，具有“-”标记较多个体组成的群体可能有较强的致害能力。TN1种群的特异片段，可能与弱致害连锁，经遗传学实验卡方验证，为质量性状基因，遵循3：1的分离比例。 四、杭州富阳地区的褐飞虱田间种群，TN1种群特有的标记条带出现的比率略低约20％左右，实验室TN1种群具该标记的个体约60％左右，但近几年来(1997—2003)该类型个体占田间种群的比例不到40％，田间能检测到该标记的比例应低于24％，二者比例比较一致。更多还原

【Abstract】 We started with the DNA polymorphism of host-associated populations of N.lugens with different virulence, and seeked the specific band of a population as a marker. On the basis of this marker, we got two relatively pure populations, and conducted biological comparison and genetic experiments. We preliminarily researched the variation of virulence of N.lugens, the main results were as follows:1. The analysis of genetic diversity of different virulence populations showed, whether female or male, the genetic diversity of inter-populations was greater than that of intra-populations, the TNI populations was reared on susceptible rice varieties showed the largest genetic variation. In the dendrogram obtained with UPGMA analysis based on the standard of similarity index (SI), every female individual of a population could be clustered into a group with no exception, and so did the male. This provided the first clearly evidence confirming that significant genetic differentiation existed between host-associated N.lugens populations with different virulence. It was also found that male and female individuals were grouped into two discrete classes, which suggested that the inheritance of virulence of N.lugens maybe associated with the sex chromosome.2. Part of RAPD bands which were specific of a population were recovered, cloned, sequenced, and transformed to SCAR, only one specific band of TNI population was successful transformed, the band was about 410bp, the frequency was about 60%. Mudgo and ASD7 populations were tested about 100 individuals, no one had this band, only the TNI population had the band, so we concluded this band was TN1 population specific band, sequence homological compared to the Genebank, there was no higher homological.3. We got two relatively pure populations of TNI population by molecular selected, that was "had the specific band population" ("+/+" population) and "had no the specific band population" ("-/-" population). The two forms were reared on the susceptible varieties, and infested to the susceptible varieties, there was no significant difference in average weight gain, average honeydew excretion, but infested to resistant varieties, there was significant difference in average weight gain, average honeydew excretion and average longevity, the value of "+/+" form was above the value of "-/-" form. The two forms were reared on resistant varieties, and infested to the resistant varieties, Fl of two forms had no significant difference in average weight gain, average honeydew excretion, but the value of the "-/-" form was above the value of "+/+" form, F2 of two forms had significant difference in average weight gain, average honeydew excretion, perhaps the population composed by individuals that had more "-" marker, the population virulence would be stronger. The special band of TN1 population maybe link with avirulence, it was quality character confirmed by genetics experiment and tested by X2-test, followed 3:1 segregation ratio.4. The field population of N.lugens in FuYang district of HongZhou, the specific band had lower frequency was about 20% in field population, the frequency of experiment population was about 60%, but from 1997 to 2003, the frequency of TN1 population was less 40% in field population, so the frequency of the specific band was less 24% in field population, and the result was same.更多还原