【作者】 马方舟；

【导师】 王韧； 万方浩；

【作者基本信息】 中国农业科学院 ， 生物安全， 2014， 博士

【摘要】 全球气候变化背景下，生物入侵的过程和结果面临复杂的变化。温度耐受性是变温昆虫时空分布和扩散动态的重要影响因素。生物有机体在极端条件下保持活力的能力对于生存意义重大。温度耐受性近来备受关注，因为对于温度耐受性的研究为我们深入地了解气候变化下生态学、种群分布、遗传变异和物种进化提供了新的视角。特别是对温度耐受性状的遗传力估计和进化潜力的分析是预测和解释入侵物种的生态适应和分布变化的重要手段。烟粉虱MED (Mediterranean)隐种最初于2003年被发现传入我国云南，在短短十几年内已经广泛分布在长江流域、东部沿海地区，甚至已经入侵到我国最北部省份黑龙江省，并有取代MEAM1隐种和本地近缘种的趋势。快速温度适应性进化是烟粉虱MED隐种种群迅速扩张的一个重要原因，但其遗传进化的内在机制尚不清楚。本论文以不同气候条件下烟粉虱MED隐种种群为研究对象，主要采用数量遗传学方法，综合分析和评估了入侵烟粉虱MED隐种的遗传与进化特征。主要研究结果如下：（1）根据目前烟粉虱MED隐种在我国的入侵现状，选择气候条件各异、并具有代表东西南北四个气候区域，最北黑龙江省、最南海南省、西北新疆吐鲁番地区和华北地区的北京市，在同一年份，选择四个地区的烟粉虱MED隐种爆发期的重叠月份内（7、8、9月），进行大田烟粉虱MED隐种的采集、筛选及相应的实验种群建立；从群体水平对不同气候条件下长期适应的烟粉虱MED隐种的耐热性进行直接高温击倒、记录击倒时间TKD的方式进行测定和比较分析，证明了不同气候条件种群的烟粉虱MED隐种在耐热性上存在显著差异；通过对同一气候条件种群中不同性别的成虫进行高温击倒记录击倒时间TKD的测定和分析，结果表明，同一种群内，烟粉虱MED四个气候条件种群的雌性成虫耐热性均显著大于雄性成虫。（2）对大田采集的代表我国东南西北四个方位的不同气候条件地区烟粉虱MED隐种种群，从群体水平上进行了以恒定低温击倒一定时间后记录其在常温下的恢复时间，即冷击倒恢复时间TRC，测定并分析了不同气候条件种群的耐寒性差异，证明了不同气候条件种群之间存在着两两之间的显著差异；在种群内部的比较中，烟粉虱MED隐种雌雄成虫在耐寒性上存在不同程度的差异，其中，北方的哈尔滨种群及北京种群雌性成虫的耐寒性显著大于雄性成虫，而热带地区的海口种群和西北地区的吐鲁番种群中，雌性成虫的耐寒性大于雄性成虫，但差异并不显著。（3）对日平均温度和日最高温度的年变化趋势相似，但温度范围差异明显的黑龙江种群和新疆种群进行亲子代杂交试验设计，测定亲本、杂交F1代及回交B1、B2代的耐热性表型值，对后代耐热性表型值进行线性剖分，并建立动物模型模型Ⅰ和模型Ⅱ。在模型似然比大于0.05情况下，应用约束最大似然法RMEL，对烟粉虱MED隐种高温耐受性遗传参数进行估计，得到了烟粉虱MED隐种基于高温45℃直接高温暴露击倒时间的耐热性遗传力和相关遗传参数，结果表明，烟粉虱MED隐种的耐热性具有高遗传力；评估了两个动物模型的似然值，认为在对烟粉虱MED隐种的高温耐受性状的遗传力估计时，建议使用模型Ⅰ进行遗传参数的估计，可以得到更为可靠的无偏估计；同时，采用半同胞组内相关法对MED隐种的遗传参数进行估计，同样得到高的狭义遗传力；鉴于烟粉虱MED隐种耐热性的高遗传力，提出该隐种在气候变暖的趋势下，烟粉虱MED隐种的高遗传力能够充分证明群体耐热表型的变异中，有很大一部分变异是可以稳定遗传的，这种稳定遗传的变异为烟粉虱耐热性进化提供了直接驱动力，是其快速适应性进化的一个有力的证据。（4）以给定低温击倒常温下记录恢复时间作为耐寒性测定标准，对不同种群进行亲子代杂交试验设计，测定不同亲本、杂交F1代及回交B1、B2代的耐寒性表型值相关参数，对后代耐寒性表型值进行线性剖分，并建立动物模型，本研究选取了模型Ⅰ和模型Ⅱ。在模型似然比大于0.05情况下，应用约束最大似然法RMEL，对烟粉虱MED隐种低温耐受性遗传参数进行估计，得到了烟粉虱MED隐种基于低温-5℃击倒10分钟后的常温下恢复时间的耐寒性遗传力和相关遗传参数，结果表明，烟粉虱MED隐种的耐寒性具有高遗传力；对比分析了两个动物学模型，模型Ⅰ和模型Ⅱ，认为模型Ⅰ可以更好的拟合营兼性孤雌生殖特点的烟粉虱耐寒性状的表型值线性剖分关系。（5）选取耐热性较高的吐鲁番种群和耐寒性较高的哈尔滨种群，分别对两个种群进行温和的高温人工选择和温和的低温人工选择，温和高温设置为31℃，温和低温设置为21℃，以高温45℃下击倒时间作为耐热性指标，对烟粉虱MED隐种在长时间多世代高低温模拟自然选择下，其耐热性在世代间的变化趋势和差异。结果表明，在温和高温的15个世代温度的正向选择后，吐鲁番种群和哈尔滨种群的耐热性均与26℃对照相比有显著提高，总体呈上升趋势；在温和低温的15个世代的温度选择后，吐鲁番种群和哈尔滨种群的耐热性均呈现先下降后上升的波动趋势，而耐热性的最低点均出现在G6代时。（6）同样选取耐热性较高的吐鲁番种群和耐寒性较高的哈尔滨种群，分别对两个种群进行温和的高温选择和温和的低温选择，温和高温设置为31℃，温和低温设置为21℃，以低温-5℃下击倒时间10分钟后记录其在室温下的恢复时间，即冷击倒恢复时间或者冷致昏恢复时间为耐寒性指标，对烟粉虱MED隐种在长时间多世代高低温模拟自然选择下，其耐寒性在世代间的变化趋势和差异。结果表明，在温和低温的15个世代温度正向选择后，吐鲁番种群和哈尔滨种群的耐寒性均与26℃对照相比有显著提高，总体呈上升趋势；在温和低温的15个世代的温度负向选择后，吐鲁番种群和哈尔滨种群的耐热性均呈整体降低趋势。更多还原

【Abstract】 With advancing global change, analysis of thermal tolerance and evolutionary potential areimportant to explain ecological adaptation and the changes in the distribution of species.Thermaltolerance is an important factor in the distribution and range dynamics in insects. Thermal tolerancehave received much attention because their investigation provides new insight into the manner in whichclimate shapes variation in the ecology, distribution, hereditary variation and evolution of species. Theinvasive whitefly B. tabaci Mediterranean cryptic species, which is an important invasive pest that isspreading from Mediterranean regions in1993, and is now widely distributed across China except Tibetand Gansu province, ranging from Yangtze River basin to east coastal area even the northest of China,with the trend to replace the native species and MEAM1cryptic species. Higher thermal tolerance wasone of the factors during the invasion and rapid expand for MED cryptic species. To reveal the variationof heat resistance and evolutionary potential in the invasive Bemisia tabaci Mediterranean crypticspecies, we selected four Chinese populations, from Harbin, N China, and Turpan, S China, Beijing MChina and Hainan W China, and conducted knockdown test under static high and low temperatureconditions. Estimate of heritability and genetic variation were based on Parent-offspring design andhalf-sibling breeding design. The main research contents and conclusions are as follows:(1) According to the current status of invasive whitefly B. tabaci Mediterranean cryptic species inour country, we chose four populations collected from different climate regions, including Harbin,northest Heilongjiang province, Haikou, southest Hainan province, Turpan, northwest Xinjiang provinceand Beijing. The field populations of MED were collected from the above regions in July, August andSeptember2012, in which MED occoured in filed at the same time in all the four regions, and then thecorresponding experimental populations were established. Knockdown test were conducted under statichigh temperature conditions. T-test results showed that there were significant differences amongdifferent populations. The heat tolerance of southern population was higher than the three northernpopulations. Heat tolercance between male and female adults of B. tabaci MED were significantdifferent.(2) Knockdown test were conducted under static low temperature conditions. ANOVA showed thatthere were significant differences among different populations on chill coma revoery time. The coldtolerance of southern population was lower than the three northern populations. Cold tolercancebetween male and female adults of B. tabaci MED were significant different both in Harbin and Beijingpopulations, but in Turpan and Haikou populations.(3) Hybrid experimental design were conducted between Heilongjiang and Xinjiang populations asthe average daily temperature and daily maximum temperature trend was similar in the two regions.Knockdown test were conducted under static high temperature conditions on parents, F1and backcrossB1, B2generations. Genetic parameters were estimated from the three generations design. Sex,generation (parents or offspring) and locations were added as fixed factors into this analysis using animal models with restricted maximum-likelihood, which facilitates analyses of unbalanced data setsand the inclusion of fixed effects. Animal models were implemented using REML method based onModelⅠand ModelⅡseperately. The phenotypic (VP) and additive (VA) variance in knockdownresistance were computed using all known relationships among individuals. We carried out Student’st-tests to determine whether variance components and heritability estimates differed significantly.Estimates of evolvability, the additive genetic coefficient of variance,100x(where x isthe sample mean), were computed as well. The narrow sense heritability (h2n) estimates of heattolerance based on parents-offspring regressions ranged from0.45to0.49. The additive geneticcoefficients of variation (CVA) concerning heat tolerance were higher than other speices. The narrowsense heritability (h2n) of heat tolerance traits and high CVAvalue of knockdown time showed thatnatural B. tabaci Mediterranean exhibited high adaptive potential for heat tolerance. Likelihood ratioindicated that ModelⅠwas more suitable for estimating genetic parameters of thermal resistant traits inthis case.(4) Knockdown test were conducted under static low temperature conditions on parents, F1andbackcross B1, B2generations between Heilongjiang and Xinjiang populations. Genetic parameters wereestimated from the three generations design. Sex, generation (parents or offspring) and locations wereadded as fixed factors into this analysis using animal models with restricted maximum-likelihood,which facilitates analyses of unbalanced data sets and the inclusion of fixed effects. Animal modelswere implemented using REML. The narrow sense heritability (h2n) of cold tolerance traits and highCVAvalue of knockdown time showed that natural B. tabaci Mediterranean exhibited high adaptivepotential for cold tolerance.(5) Artificial selection test were conducted in both Heilongjiang and Xinjiang populations under amoderate high temperature of31℃and a moderate low temperature of21℃to survey the varience andtrends of heat tolerance. The results showed that heat resistance were significantly improved bymoderate high temperatures selection after15generations in both Heilongjiang and Xinjiangpopulations compared to the control (26℃). Heat resistance were weakened at G6generations bymoderate low temperatures, but went up then in the following generations in both Heilongjiang andXinjiang populations compared to the control (26℃).(6) Knockdown test were conducted under static low temperature conditions in every threegenerations. Artificial selection were conducted in both Heilongjiang and Xinjiang populations under amoderate high temperature of31℃and a moderate low temperature of21℃to survey varience andtrends of heat tolerance. The results showed that cold resistance were significantly improved bymoderate low temperatures selection after15generations in both Heilongjiang and Xinjiang populationscompared to the control (26℃). Cold resistance were weakened after15generations moderate hightemperatures selection in both Heilongjiang and Xinjiang populations compared to the control (26℃).更多还原